Geographic Information System(Geographic Information System or Geo Information system, GIS) is sometimes called“Geoscience information system”。It is a special and very important spatial information system.It is based on computer hardware and softwareSystem supportThe whole or part of the earth's surface (includingatmosphere）AboutGeographyDistributed data is collected, stored, managed, calculated, analyzed, displayed and describedTechnical system。
Location and geographic information are bothLBSThe core of LBS is also the foundation of LBS.A simpleLongitude and latitudeCoordinates can only be recognized and understood by users when they are placed in specific geographic information and represent a certain place, sign, and orientation.The user is using theTechnology acquisitionreachposition informationAfter that, you also need to understand thegeographical environment, query and analysisenvironmental information To provide information support and services for user activities.
Geographic Information System (GIS) is a comprehensive disciplinegeographyAndCartographyAnd remote sensing andcomputer science, which has been widely used in different fields, such as input, storage, query, analysis and displayGeographyDatacomputer systemWith the development of GIS, it is also called "Geographic Information Science". In recent years, it is also called "GISGeographic information service（Geographic Information service）。GIS is a computer-based tool that canspatial information Analysis and processing (in short, mapping and analysis of phenomena and events on the earth).GIS technology combines the unique visual effect and geographical analysis function of maps with generalDatabase operation(such as query and statistical analysis).
Chinese name
Geographic Information System
Foreign name
Geographic Information System or Geo Information system, GIS
Since ancient times, almost all human activities have taken place on the earth, which is related to the position of the earth's surface (i.e. geographyspatial location ）Closely linked withcomputer technologyGeographic Information System (GIS) and“Digital Earth”、“Digital City”It plays an increasingly important role in people's production and life.
GIS can be divided into the following five parts:
People are the most important part of GIS.Developers must define various tasks to be performed in GIS and develop processing programs.Skilled operators can usually overcome the shortcomings of GIS software functions, but the opposite is not true.The best software can not make up for the negative effect of operators' ignorance of GIS.
Data, accurate and available data can affect the results of query and analysis.
Hardware, the performance of hardware affects the dataprocessing speed , whether it is convenient and possible to useOutput mode。
Software, including not only GIS software, but also various databases, mapping, statisticsimage processing And other procedures.
Composition of GIS
Process, GIS requires clear definition and consistent method to generate correct and verifiable results.
Geographic information system (GIS) technology can be applied to scientific investigationresource management、Property management, development planning, mapping and route planning.For example, a geographic information system (GIS) canEmergency planPeople innatural disasterIt is easy to calculate the emergencyreaction time, or use GIS system to find those wetlands that need to be protected from pollution.
Geographic data and geographic information
Geographic Information System Architecture Combining Google and Web Functions
In 1948, American mathematicianinformation theoryClaude Elwood Shannon, the founder of;In 1948, the famous American mathematiciancyberneticsIn his book Cybernetics, Norbert Wiener, the founder of, pointed out that "information is information, neither matter nor energy."Narrow information theoryInformation is defined as "the difference between two uncertainties", that is, the difference in people's understanding of things before and after obtaining information;Generalized information theoryIt is believed that information refers to a form of interaction between the subject (human, biological or machine) and external objects (environment, other people, biological or machine)subject and object Between all useful information or knowledge.We believe that information provides people (or systems) with knowledge about new facts in the real world through some media. It comes from data and does not change with the carrier. It hasobjectivity, practicalityTransmissibilityandShareabilityFeatures of[1]。
Information and data are both different and related.Data is a qualitative and quantitative description of a targetsource, including characters, numbers, symbols, languages, images, images, etc. It is recognizable, storableExtensibility、Compressibility、TransitivityandinterchangeabilityEtc.Information and data are inseparable. Information comes from data, and data is the carrier of information.Data is the representation of objective objects, while information is the meaning, content and interpretation of data.Processing data (operation, sorting, coding, classification, enhancement, etc.) is to get the information contained in the data.Data contains original facts, and information is the result of data processing, which is to process data into meaningful and useful forms.
As a special kind of information, geographical information also comes from geographical data.Geographic data is a symbolic representation of the relationship between various geographical features and phenomena, which refers to representationgeographical environmentThe sum of numbers, words, images, etc. of the quantity, quality, distribution characteristics and laws of the elements in.Geographic data mainly includes three parts: spatial location data, attribute feature data and time-domain feature data.Spatial location data descriptionGeographical objectThe location, which includesGeographical elementsOfAbsolute position(e.gGeodetic latitude and longitudeCoordinates), including the relative position relationship between geographical elements (such as spatial adjacency, inclusion, etc.).Attribute data is sometimes calledNon spatial data, qualitative orQuantitative indicators, such as the grade, width, starting point and end point of the highway.Time domain characteristic data is the record geographydata acquisitionorGeographical phenomenonTime or period of occurrence.Time domain characteristic data versus environmentsimulation analysis It is very important and is receiving more and more attention from the academic community of GIS.Spatial location, attributes and time domain characteristics constitute geographyspatial analysis The three basic elements of.
Geographic information is the meaning contained in geographical data, information about specific locations on the earth's surface, and information aboutGeographical entityThe nature, characteristics andmotion state And all useful knowledge.As a special kind of information, geographic information not only has the basic characteristics of general information, but also has regional and spatial characteristicsHierarchyandDynamiccharacteristic.
In today's society, people rely heavily on computers and the information processed by computers.In the computer age, information systems are partly or entirely computer basedSystem supportTherefore, computer hardware, software, data and users are the four major elements of the information system.Among them, computer hardware includes all kinds of computer processing andterminal equipment；The software is a computer that supports data acquisition, storage, processing, reproduction and answering user questionsprogramSystem;Data is the object of system analysis and processing, which forms the application basis of the system;Users are the objects served by the information system.
Since the middle of the 20th century, people have begun to develop manyComputer Information SystemThese systems use various technical means to process geographic information, including:
○ Spatial analysis technology: spatial analysis of geographical data, retrieval and query of geographical data, measurement of length, area and volume of geographical data, selection of the best location or analysis of the best path, and many other related tasks;
○Visualization technologyThe technology of displaying and expressing geographic information in the form of numbers, images, tables, etc.
The common name of such systems is Geographic Information System (GIS,Geographic Information System），It is a computer system for collecting, storing, processing, analyzing, retrieving and displaying spatial data.Compared with maps, GIS has the inherent advantage of separating data storage from data expression, so it is based on the sameBasic dataCan produce a variety of different products.
Due to different departments and different application purposes, the definition of GIS is also different.Currently, there are four views on the definition of GIS:Data orientedProcessingThe definitions of, toolkit oriented, thematic application oriented and database oriented.Goodchild defines GIS as "collection, storage, management, analysis and display of information about geographical phenomenaTechnical system”。Burrought believes that "GIS is a powerful tool to collect, store, extract, transform and display spatial data from the real world",RussiaScholars also define GIS as "a way to solve various complicated geographical related problems andInternal contactTools Collection for.The definition of database oriented is based on the definition of toolbox, which emphasizes the connection between analysis tools and databases, and considers GIS to be the combination of spatial analysis methods and data management systems.The definition of thematic application isProcess orientedOn the basis of the definition, emphasize thedata type, such asland use GIS、Traffic GIS, etc;We believe that geographic information system (GIS), supported by computer hardware and software systems, is an important tool forSurface of the earth(includingatmosphere）Aboutgeographical distributionA technical system for data acquisition, storage, management, calculation, analysis, display and description.Like other computing systems, it includes computer hardware, software, data and users.However, all data in GIS have geographical references, that is, the data passes through aCoordinate systemAssociated with a specific location on the earth's surface.
Geographyinformation systemIt is called GIS for short. Most people think it is a Geographic Information System, while others think it is a Geo information System（Geoscience information system）Wait.People's understanding of GIS is deepening and its connotation is expanding. In "GIS", the meaning of "S" includes four meanings:
One is the system, which is fromTechnical layerThis paper discusses the geographical information system from the perspective of area, resources, environment and other planning, management and analysis. It refers to the computer technology system for processing geographical data, but it emphasizes the management andAnalytical capabilityIn terms of technology, GIS means to help build a GIS tool, such as adding new functions to the existing GIS or developing a new GIS or using existing GIS tools to solve certain problems. For example, a GIS project may include the following stages:
(1) Define a problem;
(2) Obtain software or hardware;
(3) Collect and acquire data;
(4) Establish database;
(5) Implementation analysis;
(6) Explain and present the results.
Geographic information technologies here refer to technologies for collecting and processing geographic information, includingGlobal Positioning System(GPS), Remote Sensing and GIS.In this sense, GIS includes two major tasks: one is spatial data processing;The second is GIS application development.
The second is science, which is a geographical information system in a broad sense, often called geographic information science, and is a scientific system with theory and technology, meaning that research exists in GIS and otherGeographic Information TechnologyThe following theories and concepts (GIScience).
Third, it represents service. With the development of information technology such as remote sensingInternet technologyWith the application and popularization of computer technology, GIS has gradually changed from a purely technical and research-based system to aGeographic information serviceLevel transfer, such as the need for navigation, has led to the birth of navigation GISSearch EnginesGoogleThe Google Earth function has also been added, and GIS has become a part of people's daily life.When discussing at the same timeGIS technology, GIS science orGIS servicesIn order to avoid confusion, GIS is generally used to represent technology, GIScience or GISci represents geographic information science, and GIService or GISer represents geographic information service.
The fourth is studies, namely GIS=Geographic Information Studies, to study the problems caused by geographic information technologysocial problem(social context), such as legal context, private or confidential topics, economic issues of geographic information, etc.
Therefore, Geographic Information System (GIS) is an information system specially used to collect, store, manage, analyze and express spatial dataSimulated realityThe space world and the "tool" for spatial data processing and analysis can also be seen as a "resource" for people to solve space problems, and also a "science and technology" for spatial information processing and analysis[1]。
prehistoric
Fifteen thousand years ago, on the wall of the cave near Lascaux, Cro Magnon hunters in France drew the pictures of the animals they hunted.Related to these animal pictures are some lines and symbols describing migration routes and tracks.These early records are consistent with modernGeographic Information SystemA graphic file corresponds to an attribute database.
eighteenth century
eighteenth centuryTopographic mapThe modern surveying technology of mapping has been realized, and the early versions of thematic mapping have also appeared, such as scientific aspects or census data.john snow In 1854, a point was used to represent a case, which describedLondonOfCholera epidemic, which may be the first place to use geographical methods.He was rightcholeraThe research on distribution points to the source of the disease - a polluted public water pump located on Broadway Street, the central area of the cholera outbreak.John Snow disconnected the pump and finally ended the outbreak.
Early 20th century
"Photos" that divided pictures into layers in the early 20th centuryLithography”To develop.It allows the map to be divided into layers, such as one layer representing vegetation and another layer representing water.This technology is especially used for printing contour drawing, which is a labor-intensive task, but they have a separate layer, which means they can not be confused by the work on other layers.This work was originallyGlass plateAnd later,plastic filmIntroduced, with lighter, less usedstorage space , flexibility and so on.When all the layers are completed, a giant processing camera is combined to form an image.Color printingAfter the introduction, the concept of layer is also used to create a separatePrinting plate。Although the use of later layers has become one of the main typical features of contemporary GIS, the photography process just described is not considered a GIS itself - because this map has only images and no additional attribute database.
In 1967, the first truly applied GIS in the world was launched by the Federal Ministry of Forestry and Rural Development inCanadaOntarioOfOttawaR&D.The system developed by Dr. Roger Tomlinson is calledCanadian Geographic Information System(CGIS) for storage, analysis and utilization of the Canadian Bureau of Land Statistics (CLI, 1:50000 usedscale, using information about soil, agriculture, leisure,wild animal、waterfowl, forestry and land use to determine the land capacity of rural Canada.)The collected data are analyzed by adding grade classification factors.
CGIS is“Computer Graphics”It provides coverage, data digitization/scanning functions.It supports a transcontinental national coordinate system that encodes lines with true embeddednesstopological structure And store attribute and location information in a separate file.As a result of this, Tomlinson has become known as "the father of GIS", especially because of his application of coverage in spatial analysis to promote convergence of geographical data.
CGIS was not completed until the 1970s, but it took too long. Therefore, in the early stage of its development, CGIS could not compete with Intergraph to sell various productsCommercial mapApplication software supplier competition.CGIS has been used until the 1990s, and has established a huge digitalLand resource database。It was developed based onmainframeTo support a federal and provincialresource planning And management.Its capability is complex within the continentData analysis。CGIS is not used commercially.The development of microcomputer hardware makesESRISuppliers like CARIS have successfully merged most CGIS features, and combined the first generation method of separating spatial and attribute information with the second generation method of organizing attribute datadatabase structure 。1980s and 1990sIndustrial growthStimulated the application of GISUNIXWorkstations andpersonal computerRapid growth.By the end of the 20th century, the rapid growth in various systems has made it consolidated and standardized in a small number of related platforms.And users began to put forward the concept of viewing GIS data on the Internet, which requires standardization of data format and transmission.
twenty-first century
In 2001, the "China Historical Geographic Information System" (CHGIS) project was launched。[2]
characteristic
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one
Public geographical positioning basis;
two
Capable of collecting, managing, analyzing and outputting various geospatial information;
three
The system is driven by analysis model, with strong spatial comprehensive analysis and dynamic prediction ability, and can generate high-level geographic information;
four
For the purpose of geographical research and geographical decision-making, it is a human-computer interactive spatial decision support system.
If you can connect the rainfall in your state with the photos above your county, you can judge which wetland will dry up at some time of the year.A GIS system can carry out such analysis, and it can apply information from different sources in different forms.The basic requirement for source data is to determine the location of variables.Location may be determined bylongitude, latitude and altitude,Z coordinateTo mark, or by othersGeocoding systemFor example, ZIP code, orexpresswayMile sign.Any variable that can be located and stored can be fed back to GIS.Some government agencies andNon governmental organizationsProduction in progressDirect accessComputer database of GIS.Different types ofdata formatImport GIS.At the same time, the GIS system can convert numbers that are not in the form of mapsInformation conversionRecognize the form of utilization.For example, by analyzing the numbers generated by remote sensingsatellite image, you can generate a map likeDigital informationLayer.
Similarly,Demographic surveyOr hydrological table data can also be converted into map form as subject information layer in GIS system.
Data presentation
GIS data todigital dataThe form of "" represents the objective objects of the real world (roads, land use, altitude).The objective objects in the real world can be divided into twoabstract conception: Discrete objects (such as houses) and continuous object fields (such as rainfall or altitude).These two abstractions are used in GISStore dataThe two main methods are:grid(Grid) and vector.
Grid (grid) data is stored byStorage unitConsists of rows and columns.It is similar to grid (grid) images. In addition to using appropriate colors, the values recorded by each unit may also be a classification group (e.gLand useCondition), a continuous value (e.g. rainfall), or one recorded when data is not availableNull value。raster dataset The resolution of depends on the grid width in ground units.Usually, the storage unit represents a square area of the ground, but it can also be used to represent other shapes.raster dataIt can be used to represent an area or an object.
vector data UtilizedGeometryFor example, point, line (a series ofPoint coordinates）, or face (shape depends on line) to represent objective objects.For example, in the housing segmentpolygonTo represent the property boundary, and to accurately represent the position with points.Vectors can also be used to represent fields with continuous variability.utilizecontourandIrregular triangular grid(TIN) to indicate the altitude or other continuously varying values.The TIN records for these connections form atriangleConstitutive NoRegular gridPoint.The face of the triangle represents the toposurface.
Use grid orVector data modelTo express reality has both advantages and disadvantages.Grid data is set to record the same value on all points in the face, while vector format only stores data where needed, which makes the storage space required by the former larger than that of the latter.Overlay can be easily implemented for raster data, but it is much more difficult for vector data.Vector data can be similar toVectorgraphThe shape is also displayed, and the boundary of the displayed object will be blurred when the grid data is displayed as an image.
In addition to the spatial data expressed in geometric vector coordinates or grid cell positions, other non spatial data can also be stored.In vector data, these additional data are attributes of objective objects.For example, aForest resources's polygon may contain aidentifier Value and information about tree species.Cell values in grid data can store attribute information, but can also be used as identifiers related to records in other tables.
Data collection
Data acquisition - to the systeminput data——It occupies most of the time of GIS practitioners.There are several ways to import data into GIS, where it is stored in a digital format.
Printed on paper orPolyester filmThe existing data on the map can be digitized or scanned to generate digital data.DigitizerGenerate from mapVector dataAsOperatorThe boundary of track points, lines, and polygons.Scanning the map can generate raster data that can be further processed to generate vector data.
measured data From the number on the measuring instrumentdata collectionThe system is directly input into GIS.fromGlobal Positioning System(GPS) - AnotherMeasuring toolsThe position obtained in can also be directly input into GIS.Remote sensing data also plays an important role in data collectionSensor composition。Sensors include camera, digitalScannerandLidarThe platform is usually composed of aircraft and satellites.Most digital data comes from image interpretation andAerial photograph。Soft copy workstation is used to digitize directly fromdigital imageOfStereopairFeatures obtained in.These systems allow data to be captured in 2D or 3D, and their altitude is directly measured from the stereo image pair using the principle of photogrammetry.Nowadays, simulated aerial photos are first scanned and then input into the soft copy system, but with the development of high-qualityDigital cameraAs it gets cheaper, this step can be omitted.Satellite remote sensing provides another important source of space data.Here satellites use different sensor packets to passively measureActive sensorSuch as radarElectromagnetic wave spectrumorradio wavesPartialreflection coefficient。Remote sensing collection can be further processed to identify objects and classes of interest such asland cover Raster data.
In addition to collecting and importing spatial data, attribute data should also be imported into GIS.For vector data, this includes additional information about objects in the system.
After importing data into GIS, it is usually necessary to edit it to eliminate errors or further process.For vector data, you must“topologyCorrect "to perform some advanced analysis.For example, inhighway networkThe line must be connected to the node at the intersection.Errors such as backlash or overshoot must also be eliminated.For scanned maps, stains on the source map may need to be removed from the generated raster.For example, spots of dirt may connect two lines that should not be connected.
Data operation
GIS can executeData reconstructionTo convert data into different formats.For example, GIS can generate lines around all units with the same classification, and determine thespatial relationship , such as adjacency and inclusion, to convert satellite images intoVector structure。
Since digital data is collected and stored in different waysdata sourceIt may not be fully compatible.Therefore, GIS must be able to transform geographic data from one structure to another.
System conversion
Property Ownership Map and SoilDistribution mapMay be differentscaleDisplay Data。The map data in GIS must be able to be operated so that it can be compared with those obtained from other mapsData AlignmentOr match.Before digital data are analyzed, they may have to go through other processes to integrate them into GIS, such as projection andcoordinate transformation 。 The earth can be represented by a variety of models. For any given point on the earth's surface, each model may give a different set of coordinates (such as latitude, longitude, altitude).The simplest model assumes that the earth is an ideal sphere.As more measurements of the Earth accumulate, the Earth's model becomes more and more complex and accurate.In fact, some models are applied to different regions of the earth to provide higheraccuracy(e.gNorth AmericaCoordinate system, 1983-NAD83 - only suitable for use in the United States, but not in Europe).
Projection is the basic part of map making. It transforms information from a model of the earthMathematical method, which willCurved surfaceConvert to two-dimensional media (such as paper or computer screen).Different types of maps should use differentProjection system, because each projection system has its own suitable use.For example, a projection that can accurately reflect the shape of the continent will distort the relative size of the continent (translated in EnglishWikipedia）
spatial analysis
The ability of spatial analysis is the main function of GIS, and also the main feature that distinguishes GIS from computer mapping software.Spatial analysis is based onspace objectThe space position, connection and other aspects of space to study things, and make a quantitative description of space things.Generally speaking, it only answers What, Where, How and other questions, but does not (can) answer Why.Spatial analysis requires complexMathematical toolsThe most important ones are spatial statistics, graph theorytopology、Computational geometryIts main task is toSpatial compositionDescribe and analyze to obtain, describe and recognize spatial data;Understand and explain the background process of geographical patterns;Simulation and prediction of spatial processes;RegulationGeospatialThe events that occurred on the.
Spatial analysis technology is related to many disciplines, such as geography, economicsRegional science, atmospheregeophysical, hydrology and other specialized disciplines provide them with knowledge and mechanism.
In addition to GIS software bundled with spatial analysis module, there are also some special spatial analysis software, such as GISLIB, SIM, PPA, Fragstats, etc.
modeling system
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Data modeling
It is difficult to correlate wetland maps with rainfall recorded in different places such as airports, television stations and schools.However, GIS can describe the two-dimensional and three-dimensional characteristics of the surface, underground and atmosphere.
For example, GIS can quickly map the rainfall line reflecting rainfall.
Such figure is called rainfallLine diagram。Through the measurement of a limited number of points, the characteristics of the entire surface can be estimated, and this method is very mature.A two-dimensional rainfall line map can be used with other layers in the same area in GISStack analysis。
Topology modeling
In the past 35 years, have you ever operated any gas station or factory near the wetland?Are there any such facilities that meet the conditions within 2 miles and above the wetland?GIS can identify and analyze this kind ofspatial relationship 。these ones hereTopological relationshipAllow complexSpatial modelingAnd analysis.The topological relationship between geographical entities includes connection (what is connected with what), inclusion (what is in what), and proximity (the distance between the two).
Network modeling
If all factories near the wetland discharge chemicals into the river at the same timematerial，Then the quantity of pollutants that can damage the environment can be simulated through GIS[1]。GIS can simulate pollutants alonglinear networkThe path of diffusion (of a river).Such as slope, speedLimits, pipe diameter and other values can be incorporated into this model to make the simulation more accurate.networkmodelingUsually used fortraffic planning , hydrological modeling and underground pipe network modeling.
GIS
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Geographic information is just a pile of number records, which need to be represented by appropriate software;At the same time, the establishment of geographic information database also depends on the help of appropriate software to informationize geographic data.CurrentlyBusiness communityThe market of the two GIS giantsESRIandMapinfoBut they can also provide a complete set of geographic information systems for customers to use.Government and military organizations often use specially made software, such as open source GRASS or other special systems, to meet their special needs.Although there are many free tools for reading GIS data, the geographical information easily accessible to the general public still has to rely onGoogle EarthorMicrosoftSuch as Virtual Earth.The information provided by these systems tends to focus on the regional center. For example, you can clearly find a parking space in a remote town in the United States, but you can't clearly see a parking space located inSeoulJiangnan DistrictThe street.
Internet connection programming interface
stayInternet Services Today, many geographic information systems provide programming interfaces, allowing users to create their own geographic information pages through these interfaces and systems.These programming interfaces can be usedVBAorJavaScriptOf.Users can easily provide link pages of satellite pictures or maps, and even add driving routes orgeographical positionAnd other information.
Mobile GIS
By combining with mobile devices, GIS can provide users with real-time geographic information.Generally, the navigation device on the car is integratedsatellite positioning Equipment (GPS) and Geographic Information System (GIS)Composite system；Once very popular in Hong KongMap king, a set can be installed on thePDAOr a real-time map system on a mobile phone.
automobileNavigation systemIt is a special case of GIS. In addition to the content of general GIS, it also includes the database of driving and related information of each road.This database usesVector representationThe route, direction, road section and other information of drivingNetwork topologyTo determine the best route.Geographic data file(GDF) is an ISO standard for describing map data for navigation systems.Car navigation systemCombinedMap matching, GPS positioning and to calculate the position of the vehicle.The map resource database is also used fortracksPlanning, navigation, and possiblyActive safety system, assisted driving, Location Based Services (LBS) and other advanced functions.Map resources are applied to the database of the car navigation systemDatabase management。
gvSIGIt is a JAVA basedDesktop Geographic Information SystemIt is also a powerful tool for developing GIS.It includes many functions such as spatial data analysis,Map editing, Map design, etc.GvSIG gotSpainSome governments and companies are involved and issued based on GNU/GPL licenses.GvSIG can work well in Windows andLinuxOn the platform.GvSIG supports some common GIS systemsSpatial data standardFormat (shapefile,DXF,DWG,DGN,ECW,MrSID,TIFF,JPG2000,KML,GMLEtc.).GvSIG complianceOGC(Open Geospatial Consortium) standard, which means that it can read local data as well as remote data through WMS, WFS, and WCS.
advantage: onSeamless integrationAnd flexibility.GIS developers do not have to master specialized GISsystem developmentLanguage, as long as you are familiar with the common Windows based platformIntegrated development environmentTo understand the properties, methods and events of controls, you can realize the development of GIS system.
Integrated tools
Integrated GIS development tool means a collection of variousfunctional module GIS development kit.Common ones: ESRIArcGIS, MapInfoMapInfoGeoconcept of GEOCONCEPT Group, etc.
advantage: Each function has formed an independent and complete system, which provides powerful data input and output function, spatial analysis function, good graphics platform and reliable performance. The disadvantage is that the system is complex, huge, high cost, and difficult to compare with othersApplication system integration。
Modular tools
The modular GIS development tool is to divide the GIS system into some modules to run according to its functions.The most common one is MGE of Intergraph.
advantage: The developed GIS system has strong pertinence and is convenient forSecondary developmentAnd applications.
Network Tools
WebGIS refers to the GIS geographic information system based on the Internet platformnetwork techniqueTo expand and improve the new technology of GIS.WebGIS is still in its infancyDevelopment stageHowever, many companies have launched WebGIS development toolsMap SuiteWeb Edition, MapInfo ProServer of MapInfo Company, Intergraph CompanyGeoMedia Web MapGeoconcept Internet Server (GCIS) of GEOCONCEPT Group.
advantage: The developed GIS system has goodScalabilityAnd cross platform features, making GIS truly popular.
development space
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Many disciplines benefit from GIS technology.The active GIS market has led to the low cost andContinuous improvement。These developments in turn promote the wider application of this technology in science, government, enterprises and industries, including real estate, public healthCrime map, national defense, sustainable developmentnatural resources、Landscape architecture、archaeology、community planning , transportation and logistics.Geographic information system also differentiatedLocation service(LBS)。LBS uses GPS to pass the relationship between the location and the fixed base stationMobile DevicesDisplay its location (the nearest restaurant, gas station,Fire Hydrant）, mobile device (friend, child, a police car) orEchoTheir location is displayed on a central server or other processing.With the GPS function and increasingly powerful mobile electronics (mobile phonespad、Notebook computer）Integration, these services continue to develop.
Universal brand
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Earlier, Esri had put forward the concept of "beautifying life with geographical design and sharing geographical knowledge with everyone".Up to now, Esri has deeply integrated this concept into its latestArcGIS10.1。ArcGIS 10.1 willSpatial information technologyUniversalization will penetrate into everyone's work and life in the future.
“Universal GIS”ArcGIS10.1 has completely built a bridge from the end to the cloud, making the shelved GIS from professionals to the public graduallyspatial information Creator and user ofTight connection, viaArcMap、Portal for ArcGIS、ArcGIS Server andmobile terminal Everyone can become a sharer and user of spatial information on ArcGIS App, so as to meet various needs of the public.
In recent two years, the industry generally believes that GIS will develop in the direction of specialization, universality and intelligence, and universal GIS will undoubtedly lead the future development of geographic information industry.The development of pervasive computing can provide people with moreinformation service, improving the computerPerception, enhance social relevance, have strong characteristics of active interaction and natural interaction, bring convenient, simple and fast information applications to people's lives, andControllability, is an important part of GIS industryDevelopment trendone of.
The future GIS will be a universal GIS, which can be used by anyone. GIS services can be accessed anywhere with any terminal, and it is not limited to professional terminals, so that ordinary users can access through multiple media.This also benefits fromcloud computingWith the rapid development of technology, mobile terminals and other aspects, more demands of users can be easily realized.In a universal environment, what we need to do is to create a GIS environment for everyone. We need to express our knowledge and experience in the form of maps, so that users can easily accessMap data。
along withcloud computingWith the rapid development of new technologies such as Internet of Things and mobile terminals, the future GIS will be a universal GIS, and the increasingly diverse needs of users will be easily addressed.No matter who can use it, no matter where you are, no matter what terminal you hold, you can access GIS services, not only on professional terminals, but also through multiple media for ordinary users.
OGC standard
The Open Geography Federation is an international industry federation of 384 companies, government agencies, universities and individuals involved in a concerted process to develop open geographic processing specifications.Open interface and protocol defined by OpenGIS specification, supportingInteroperabilitySolutions, network, wireless and location services and mainstream IT.Make complex spatial information and services available to authorized technical developers in various applications.Open Geographic Consortium protocol including networkMap serviceWMS and network function service WFS.GIS is composed ofOGCThe products are divided into two types, which are based on complete and accurate software conforming to OGC specifications.Geographic Information Systemtechnical standardPromote the communication of GIS tools.Compatible products comply with OpenGIS specificationssoftware product 。When a product is tested and proved to be compatible through the OGC test project, the product is automatically registered as "compatible" at this location.Real software products, that is, software products that implement the OpenGIS specification but have not passed the compatibility test.Compliance testing cannot be applied to all specifications.Developers can register their products as implementation drafts or approved specifications, and OGC has the right to review and confirm each item.
WEB Map
In recent years,Map applicationExplosiveSpread to websites, such asGoogleMaps and Bing Maps.These websites enable the public to obtain a large amount of geographical data.Some of them, likeGoogle Maps And OpenLayers, which announcedAPIEnables users to create custom applications.these ones heretool kitStreet map and antenna are generally provided/satellite image、Geocoding, search and routing.Other applications of geographic information on publishing networks include GeognoSIS of Cadcorp, ArcIMS server of ESRI,Google Earth, Google merges tables and open sourcesuccedaneumMapServer，MapnikAnd GeoServer.
Maps are often used to explore the Earth and exploit its resources.Geographic information system technology, as an expanded map science, has improved thework efficiencyAnd traditional map analysis capabilities.When the scientific community identifies the environmental consequences of human activities that affect climate change, GIS technology is becoming a basic tool to understand the impact of environmental changes over time.GIS technology enables data from various sources to be compared with existing maps and data fromEarth observation satelliteThe latest information is combined with the output of the climate change model.This can be done in complexNatural systemHelp understand the impact of climate change.One of the classic examples isarcticStudy of ice melting.The output of a geographic information system in the form of a map combined with satellite images allows researchers to view their research objects in an unprecedented way.These photos are useful for transmitting climate change effects toNon scientificWorkers are also very important.
semantics
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World Wide Web ConsortiumOfSemantic WebThe tools and technologies emerging in the movement have been proven to be effective indata Integration It is very useful in questions.Accordingly, this technology has been proposed as a way to promoteInteroperabilityAnd data reuse, and a new analysis mechanism is enabled.
Ontology is a key component of this semantic approach, because they follow a machine readableFormal specifications。This, in turn, makesGeographyInformation systems focus on the meaning of a piece of data, not its syntax or structure.The temporary ontology is in GISapplication area Developed, e.g. byBritish Topographic SurveyAnd NASAJet Propulsion LaboratoryThe SWEET ontology is developed into the water text ontology.In addition, simple ontology and semanticsMetadata Standards The World Wide Web Consortium GeographyCultivationPublished by the group for online presentationGeospatial data。
Social application
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With the popularization of GIS in decision-making, scholars have begun to consider the social impact of GIS.Some people believe that the production, distribution, utilization and expression of geographical information are largely related tosocial environmentofOther relevant topics include discussion of copyright, privacy and censorship.The more optimistic social application of GIS is to take it as aPublic participationTo apply.
Statistics show that by the end of the 11th Five Year Plan, the total value of China's geographic information industry has exceeded 100 billion yuan;By the end of the 12th Five Year Plan, this figure is expected to exceed 200 billion yuan.The doubled scale will bring huge benefits to the upstream and downstream enterprises of the geographic information industry chainMarket space。
The plan proposes to accelerate the integration of geographic information resources and the construction of digital city.According to statistics, during the 11th Five Year Plan period, there were 130 pilot cities and cities for digital city construction in China.Wang Chunfeng, deputy director of the National Bureau of Surveying, Mapping and Geographic Information, said that during the "12th Five Year Plan" period, the construction of digital cities will be comprehensively promoted throughout the country, striving to complete all 333Prefecture level cityAnd partially conditionalcounty-level cityDigital city construction.
2011 Surveying and Mapping released by the National Bureau of Surveying, Mapping and Geographic InformationKey pointsIt is required to further accelerate the pace of digital city construction, and strive to complete and start the construction of more than 100 digital cities in 2011, so as to make the digital cities cover more than 2/3 of the nationalPrefecture level city。industry insidersIt is pointed out that based on such construction speed, in the next 3-5 years, the digital city management platform willMarket capacityIt will exceed 10 billion yuan.
It is worth noting that at the end of the 11th Five Year Plan, the public editionNational Geographic Information Public Service Platform“Celestial map”It is opened and has an important impact.The plan proposes that during the "12th Five Year Plan" period, the service function of "Tiantu" will be extended to provincial and municipal levels, and the promotion and application of "Tiantu" will be strengthened to build it into the InternetContent ServicesChinaOwn brand。
Strive to be included in the emerging industry planning
The plan also said that it would continue to improveIndustrial development policyAnd strive to incorporate the geographic information industry into the national strategic emerging industry planning.Encourage geographyInformation enterpriseParticipate in government procurement and promote enterprises' independent innovation products in the governmentinvestment projects And strive to realize that the proportion of equipment made in China in major surveying and mapping projects exceeds 50%.
The plan also proposes that we should deeply explore the location based geographic information servicesmarket potentialGreatly improve geographic information service businessCoverageAnd market profitability.It includes increasing the integrated application of geographic information technology and related technologies, and cultivating new economic growth points.Increase geographic information technology and locationservice productsIn e-commercee-government、Intelligent Transportation 、Modern logisticsApplication in such aspects as;Develop electronic game products and geographic information based on geographic informationtelevision channelAnd based onInternet of ThingsLocation service products.
Analysts pointed out that with the introduction of a number of guiding policies, upstream and downstream enterprises in the geographic information industry chain will usher in huge market opportunities.
Guard Tour Application
Geographic Information System (GIS for short).It is a technical system that, supported by computer hardware and software systems, collects, stores, manages, calculates, analyzes, displays and describes the relevant geographical distribution data in the whole or part of the earth's surface (including the atmosphere) space.GIS is usually used in combination with GPS.For large-scale outdoor patrol inspection, patrol personnel hold GPSPatrol, real-time receptionGPS satellite positioningMessage (timeLongitude and latitude）, and press the presettime intervalAutomatically send or manually send location information to wireless communication in a specific locationFront end processor。After receiving the positioning information, the wireless communication front-end processor willdata transmissionTo Administrationsystem platform , system software adopts GISElectronic mapTechnology,dynamic display The detailed information of the patrol point can be obtained by GIS analysis after playback of the patrol track.
1. Master mathematics, physicscomputer scienceBasic theories and knowledge in such aspects as;
2. Master the basic theories, knowledge and experimental skills of GIS and cartography, as well as the basic principles and methods of GIS technology development;
4. Understanding the countryScience and technology policy, intellectual property, sustainable development strategy and other relevant policies and regulations;
5. Understand the theoretical frontier, application prospect and latest development trends of GIS, as well as GISIndustrial developmentStatus;
6. Master data querybibliography retrievalAnd applicationmodern information technology Basic methods for obtaining relevant information;Have definite experimental design, create experimental conditions, summarize, sort out and analyze experimental results, write papers, and participate inacademic exchangeAbility.
