History of development

The Geographical Information System was made by Roger Tomlinson in the year 1968 in his paper “A Geographic Information System for Regional Planning”. ^[6] Tomlinson is also acknowledged as the “father of GIS”. ^[7]

Previously, one of the first applications of spatial analysis in epidemiology is the 1832 ” Report on the progress and effects of cholera in Paris and the Seine department “. ^[8]The French geographer Charles Picquet Represented the 48 districts of the city of Paris by halftone color gradient selon the number of Deaths by cholera per 1,000 habitants. In 1854 John Snow determined the source of a cholera outbreak in Londonby marking points on a map where the cholera victims lived, and connecting the cluster with a source of water. This is one of the earliest successful uses of a geographical methodology in epidemiology. While the basic elements of topography and the subject of previously existing cartography , the John Snow map was unique, using cartographic methods not only to depict but also to analyze clusters of geographically dependent phenomena.

The early 20th century saw the development of photozincography , which allowed maps to be split into layers, for example one layer for vegetation and another for water. PARTICULARLY Reviews This was used for printing contours – drawing thesis Was a labor-intensive task purpose HAVING em we separate layer Meant They Could Be Worked one without the other layers to the confused draftsman . This work Was Originally drawn on glass plates goal later plastic Filmwas introduced, with the advantages of being lighter, using less brittle, among others. When all layers were finished, they were combined into one image using a large process camera. Once color printing has been used, the layers have been used for each color. While the use of these types of features has become typical of a contemporary GIS, the photographic process is just not considered to be GIS in itself – as the maps were just images with no database to link them to.

Computer hardware development developed by nuclear weapon researches to general-purpose computer “mapping” applications by the early 1960s. ^[9]

The year 1960 saw the development of the world’s first operational GIS in Ottawa, Ontario , Canada, by the Federal Department of Forestry and Rural Development. Developed by Dr. Roger Tomlinson , It was called Expired the Canada Geographic Information System (CIGS) and Was used to store, analyze, and Manipulate data file Managed for the Canada Land Inventory – an attempt to determine the land capability for rural Canada by mapping information about soils , agriculture, recreation, wildlife, waterfowl , forestryand land use at a scale of 1: 50,000. A rating classification factor was also added to permit analysis.

CGIS was an improvement over “computer mapping” applications as it provided capabilities for overlay, measurement, and digitizing / scanning. It has a national coordinate system that spanned the continent, coded lines as arcs having a true embedded topology and it stored the attribute and locational information in separate files. As a result of this, Tomlinson has become known as the “father of GIS”, particularly for his use of overlays in the spatial analysis of convergent geographic data. ^[10]

CGIS lasted in the 1990s and built a large digital land resource database in Canada. It was developed as a mainframe -based system in support of federal and provincial resource planning and management. Its strength is continent-wide analysis of complex datasets . The CGIS was never commercially available.

In 1964 Howard T. Fisher formed the Laboratory for Computer Graphics and Spatial Analysis at the Harvard Graduate School of Design (LCGSA 1965-1991), where a number of important theoretical concepts in spatial data handling were developed, and which by the 1970s had distributed seminal software code and systems, such as SYMAP, GRID, and ODYSSEY – that served as sources for future commercial-development to universities, research centers and corporations worldwide. ^[11]

GIS systems ( MOSS and GRASS GIS ) were in development, and by the early 1980s, M & S Computing (later Intergraph ) along with Bentley Systems Incorporated for the CAD platform, Environmental Systems Research Institute ( ESRI ), CARIS (Computer Resource Information System), MapInfo Corporation and ERDAS (Earth Resource Data Analysis System), GIS Software, Successfully Incorporating Many of the CGIS Features, generating approach to organizing data in database structures.^[12]

In 1986 Mapping Display and Analysis System (MIDAS), the first desktop GIS product ^{[ citation needed ]} Was released for the DOS operating system. This was renamed in 1990 to MapInfo for Windows when it was ported to the Microsoft Windows platform. This began the process of moving GIS from the research department into the business environment.

By the end of the 20th century, the rapid growth in various systems had been consolidated and applied to GIS data over the Internet . More recently, open source GIS packages can be customized to perform specific tasks. Increasingly geospatial data and mapping applications are made available through the World Wide Web (see GIS as a Service ). ^[13]

Several articles on the history of GIS have been published. ^[14] [15]

GIS techniques and technology

Modern GIS technologies uses digital information, for which they are used. The most common method of data creation is digitization , where a hard copy of a CAD program, and geo-referencing capabilities. With the wide availability of ortho-rectified imagery (from satellites, aircraft, Helikites and UAVs), heads-up digitizing is becoming the main avenue through which geographic data is extracted. Heads-up digitizing involves the tracing of geographic data directly on top of the aerial imagery instead of the traditional method of tracing the geographical form of a digitizing tablet (heads-down digitizing). ^{[clarification needed ]}

Relating information from different sources

GIS uses spatio-temporal ( space-time ) location as the key variable index for all other information. Just as a relational database containing a variable index of variables, GIS can relate otherwise. The key is the location and / or extent in space-time.

Any variable that can be located spatially, and also temporally, can be referenced using a GIS. Locations where extents or extents in space-time may be recorded as dates / times of occurrence, and x, y, and z respectsrepresenting, longitude , latitude , and elevation , respectively. These GIS coordinates can be used for the analysis of space-based reference (for example, movie frame number, gage station, mile-marker, surveyor benchmark, building address, street intersection, waterfall sounding, POS or CAD drawing origin / units). Units applied to recorded temporal-spatial data can vary widelymap projections ), but all Earth-based spatial-temporal location and extent references should, ideally, be relatable to one another and ultimately to a “real” physical location or extent-space-time.

Related information is available from the following table, which can be analyzed, interpreted and represented. ^[16] This key characteristic of GIS has been introduced to new avenues of scientific inquiry into behaviors and patterns of real-world information that has not been systematically correlated .

GIS uncertainties

GIS accuracy depends on data source, and how it is encoded to be data referenced. Land surveyors have been able to provide a high level of positional accuracy utilizing the GPS- derived positions. ^[17] High-resolution digital terrestrial and aerial imagery, ^[18] powerful computers and Web technology are changing the quality, utility, and expectations of GIS to serve society on a large scale, but nevertheless there is another source of data that affects overall GIS accuracy like paper maps, though these may be of limited use in achieving the desired accuracy.

In Developing a digital topographic database for a GIS, topographical maps are the source of hand and aerial photography and satellite imagery are extra sources for collecting data and attributes Identifying qui peut être mapped in layers over a facsimile of scale rental. The scale of a map and geographical representation rendering area like ^{[ clarification needed ]} are very significant aspects since the content information Mainly depends on the scale set and resulting and locatability of the map’s representations. In order to digitize a map, the scanned into a raster format, and resulting raster datarubber sheeting / warping technology process.

A quantitative analysis of maps brings accuracy issues into focus. The electronic and other equipment used to make measurements for GIS is far more accurate than the machines. All geographical data are inherently inaccurate, and these inaccuracies will be propagated through GIS operations in which they are difficult to predict.

Data representation

GIS data represents real objects (such as roads, land use, elevation, trees, waterways, etc.) with digital data determining the mix. Real objects can be divided into two abstractions: discrete objects (eg, a house) and continuous fields (such as rainfall amount, or elevations). Traditionally, there are two broad methods used in GIS for both types of abstraction mapping: raster images and vector . Points, lines, and polygons are the stuff of mapped location attribute references. A new hybrid method of storing data is that of identifying point clouds, which combines three-dimensional points with RGB information at each point, returning to ” 3D color imageGIS thematic maps then become more and more visually descriptive of what they are set to show or determine.

For a list of popular GIS file formats, such as shapefiles , see GIS file formats. Popular GIS file formats .

Data capture

Data capture-entering information into the system-consumes much of the time of GIS practitioners. There are a variety of methods used in GIS where it is stored in a digital format. ^[19]

Existing data printed on paper PET film maps can be digitized or scanned to produce digital data. A digitizer produces vector data as an operator traces points, lines, and polygon boundaries from a map. Scanning a map results in raster data that could be further processed to produce vector data.

Survey data can be directly entered into a GIS from digital data collection systems using a technique called coordinate geometry (COGO) . Positions from a Global Navigation Satellite System (GNSS) like Global Positioning System can also be collected and then imported into GIS. A current trend in data collection gives users the ability to utilize field computerswith the ability to edit data using wireless connections or disconnected editing sessions. GPS units with decimeter accuracy in real time. This eliminates the need to post process, import, and update the data in the office after fieldwork has been collected. This includes the ability to incorporate a laser rangefinder . New technologies also allow users to create maps in the field, making more efficient and more accurate mapping.

Remotely sensed data also plays an important role in data collection and consistency of sensors attached to a platform. Sensors include cameras, digital scanners and lidar , while platforms usually consist of aircraft and satellites . In England in the mid-1990s, hybrid kite / balloons called helikites first pioneered the use of compact airborne digital cameras as airborne geo-information systems. Aircraft measurement software, accurate to 0.4 mm was used to link the photographs and measure the ground. Helikites are inexpensive and more accurate than aircraft. Helikites can be used over roads, railways and towns where unmanned aerial vehicles (UAVs) are banned.

Recently aerial data collection is becoming possible with miniature UAVs . For example, the Aeryon Scout was used to map a 50-acre area with a distance of 1 inch (2.54 cm) in only 12 minutes. ^[20]

The majority of digital data currently comes from the photo interpretation of aerial photographs. Soft-copy workstations are used to digitize features directly from stereo pairs of digital photographs. These systems are able to be captured in two and three dimensions, with elevations measured directly from a stereo pair using the principles of photogrammetry . Analog aerial photos must be scanned before being entered into a soft-copy system, for high-quality digital cameras this step is skipped.

Satellite remote sensing provides another important source of spatial data. Here satellites use different sensor packages to passively measure the reflectance from parts of the electromagnetic spectrum or radio waves That Were feels out from an active sensor radar Such As. Remote sensing collects raster data that can be further processed by different groups.

When data is captured, the data should be captured with relative accuracy or absolute accuracy, since this data could not be used.

After entering data into a GIS, the data usually requires editing, to remove errors, or further processing. It must be made “topologically correct” before it can be used for some advanced analysis. For example, in a road network, lines must connect with nodes at an intersection. Such as undershoots and overshoots must also be removed. For scanned maps, blemishes on the map may be removed from the resulting raster . For example, a fleck of dirt might connect two lines that should not be connected.

Raster-to-vector translation

Data restructuring can be performed by a GIS to convert data into different formats. For example, a GIS may be used to convert a satellite image to a vector structure by generating lines around all cells with the same classification, while determining the cell spatial relationships, such as adjacency or inclusion.

More advanced data processing can occur with image processing , a technique developed in the late 1960s by NASA and the private sector to provide contrast enhancement, false color rendering and a variety of other techniques including use of two dimensional Fourier transforms . Since digital data is collected and stored in various ways, the two data sources may not be entirely compatible. So a GIS must be able to convert geographic datafrom one structure to another. In so doing, the implicit assumptions behind different ontologies and classifications require analysis. ^[21] Object ontologies have more prominence as a consequence of object-oriented programmingand sustained work by Barry Smith and co-workers.

Projections, coordinate systems, and registration

The earth can be represented by various models of latitude and longitude (eg, latitude, longitude, elevation) for the earth’s surface. The simplest model is to assume the earth is a perfect sphere. As more measurements of the earth have accumulated, the models of the earth have become more sophisticated and more accurate. In fact, there are models called Expired datums That apply to different areas of the earth to Provide Increased accuracy, like NAD83 for US measurements, and the World Geodetic System for worldwide measurements.

Spatial analysis with geographical information system (GIS)

GIS spatial analysis is a rapidly changing field, and GIS packages are widely available as standard toolsets, as optional toolsets, as add-ins or ‘analysts’. In many instances, these are provided by the original software vendors, while others have been developed and provided by third parties. Further, many products offer software development kits (SDKs), programming languages ​​and language support, scripting facilities and / or special interfaces for developing one’s own analytical tools or variants. The website “Geospatial Analysis” and associated book / ebook attempt to provide a comprehensive understanding of the subject. ^[22]The term ” spatial intelligence ” is a new dimension to business intelligence termed ” spatial intelligence ” which, when it is openly delivered via intranet, access to geopolitics and social network data. Geospatial intelligence , based on GIS spatial analysis, has also become a key element for security. GIS as a whole can be described as a vectorial representation or any other digitization process.

Slope and appearance

Slope can be defined as a steepness or gradient of a unit of land, usually measured as an angle in degrees or as a percentage. Aspect can be defined as the direction in which a unit of terrain faces. Aspect is usually expressed in degrees from north. Slope, aspect, and surface area in the field of analysis are all derived from neighborhood operations using elevated values ​​of a neighboring cell. ^[23] Slope is a function of resolution, and the spatial resolution used to calculate slope and aspect should always be specified. ^[24] Various authors have compared techniques for calculating slope and aspect. ^{[25] [26] [27]}

The following method can be used to derive slope and aspect:
The elevation is a perpendicular tangent (slope) passing through the point, in an east-west and north-south direction. These two tangents give two components, ∂z / ∂x and ∂z / ∂y, which then be used to determine the overall direction of slope, and the aspect of the slope. The gradient is defined as a vector of equal components in the direction of the surface. ^[28]

The calculation of the overall 3×3 grid slope S and part A for methods That determines east-west and north-south component Use the following formulas respectivement:

{\ displaystyle \ tan S = {\ sqrt {\ left ({\ frac {\ partial z} {\ partial x}} \ right) ^ {2} + \ left ({\ frac {\ partial z} {\ partial y}} \ right) ^ {2}}}}

{\ displaystyle \ tan A = \ left ({\ frac {\ left ({\ frac {- \ partial z} {\ partial y}} \ right) {\ left ({\ frac {\ partial z} {\ partial x}} \ right)}} \ right)}

Zhou and Liu ^[27] describe another formula for calculating aspect, as follows:

{\ displaystyle A = 270 ^ {\ circ} + \ arctan \ left ({\ frac {\ left ({\ frac {\ partial z} {\ partial x}} \ right)} {\ left ({\ frac { \ partial} {\ partial y}} \ right)}} \ right) -90 ^ {\ circ} \ left ({\ frac {\ left ({\ frac {\ partial z} {\ partial y}} \ right)} {\ left | {\ frac {\ partial z} {\ partial y}} \ right |}} \ right)

Data analysis

It is difficulty to recounts wetlands maps to rainfall water equivalent Recorded at different point Such as airports, television stations, and schools. A GIS, however, can be used to depict two- and three-dimensional characteristics of the Earth’s surface, subsurface, and atmosphere of information points. For example, a GIS can easily generate a map with isopleth or contour linesthat indicate different amounts of rainfall. Such a map can be thought of as a rainfall contour map. Many sophisticated methods can estimate the characteristics of surfaces from a limited number of points measurements. A two-dimensional contour map created by GIS covering the same area. This GIS derived map can provide additional information – such as the viability of water power potential as a renewable energy source. Similarly, GIS can be used to compare other renewable energy resources to find the best geographic potential for a region. ^[29]

Further, from a series of three-dimensional points, or digital elevation model , isopleth lines of elevation contours can be generated, along with slope analysis, shaded relief , and other elevation products. Watersheds can be defined for any given distance, by computing all of the areas contiguous and upholding from any point of interest. Similarly, an expected thalweg of where surface water would be intermittent and permanent streams can be computed from elevation data in the GIS.

Topological modeling

A GIS can recognize and analyze the spatial relationships that exist within the digitally stored spatial data. These topological relationships allow for complex spatial modeling and analysis to be performed. Topological relationships between geometric entities traditionally include adjacency (what adjoins what), containment (what encloses what), and proximity (how to close something is to something else).

Geometric networks

Geometric networks are linear networks of objects that can be used to represent interconnected features, and to perform special spatial analysis on them. A geometric network is composed of edges, which are connected to junction points, similar to graphs in mathematics and computer science. Just like graphs, which can be used to compare different interconnected features. Geometric networks are often used to model road networks and public utility networks, such as electric, gas, and water networks. Network modeling is also used in transportation planning , hydrology modeling, and infrastructure modeling.

Hydrological modeling

GIS hydrological models à la description des éléments des hydrologiques et de la hydrologie du lac, avec la analyze des variables d’une slope, de l’ aspect et la watershed ou catchment area . ^[30] Field analysis is fundamental to hydrology, since water always flows down to slope. ^[30] As basic field of analysis of a digital elevation model (DEM)Calculus of slope and aspect, DEMs are very useful for hydrological analysis. Slope and aspect can be used to determine direction of surface runoff, and hence for accumulation for the formation of streams, rivers and lakes. Areas of divergence can also give a clear indication of the boundaries of a catchment. Once a flow has been created, it can be done at a certain point. ^[30] More details can be added to the model, such as roughness, vegetation types and soil types, which can influence infiltration and evapotranspiration rates, and hence influencing surface flow. One of the main uses of hydrological modeling is in environmental contamination research .

Cartographic modeling

Dana Tomlin probably coined the term “cartographic modeling” in his PhD dissertation (1983); he later used it in the title of his book, Geographic Information Systems and Cartographic Modeling (1990). ^[31] Cartographic modeling refers to a process where several thematic layers of the same are produced, processed, and analyzed. Tomlin used raster layers, but the overlay method (see below) can be used. Operations on map layers can be combined into algorithms, and eventually into simulation or optimization models.

Map overlay

The combination of multiple spatial datasets (dots, lines, or polygons ) creates a new output vector dataset, visually similar to stacking multiple maps of the same region. These overlays are similar to Venn diagram overlays. A union overlay combines the geographical features and attribute tables of both inputs into a single new output. An intersectoverlay defines the area where both inputs overlap and retains a set of attribute fields for each. A symmetric difference overlay defines an output area that includes the total area of ​​both inputs except for the overlapping area.

Data extraction is a GIS process similar to vector overlay, but it can be used in vector or raster data analysis. Data extraction involves a “clip” or “mask” to extract the features of a data set that falls within the spatial extent of another dataset.

In raster data analysis, the overlay of datasets is accomplished through a process known as “local operation on multiple rasters” or ” map algebra “, through a function that combines the values ​​of each raster matrix . This function can be used to analyze the impact of various factors on a geographic phenomenon.

Geostatistics

Geostatistics is a branch of statistics that deals with field data, spatial data with a continuous index. It provides methods to model spatial correlation, and predictable values ​​at arbitrary locations (interpolation).

When phenomena are measured, the observation methods dictate the accuracy of any subsequent analysis. Due to the nature of the data (eg traffic patterns in an urban environment, weather patterns over the Pacific Ocean ), a constant or dynamic degree of precision is always lost in the measurement. This loss of precision is determined from the scale and distribution of the data collection.

To determine the statistical relevance of the analysis, an average is determined that points (gradients) may be included to determine their predicted behavior. This is due to the limitations of the applied statistical information and methods, and interpolation is required to predict the behavior of particles, points, and locations that are not directly measurable.

Interpolation is the process by which a surface is created, usually a raster dataset, through the input of data collected at a number of sample points. There are several forms of interpolation, where each treats the data differently, depending on the properties of the data set. In comparing interpolation methods, the first consideration should be exact or approximate. Next is the method is subjective, a human interpretation, or objective. Then there is the nature of transitions between points: they are abrupt or gradual. Finally, there is a method that is global, or local where an algorithm is repeated for a small section of field.

Interpolation is a valid measurement because of a spatial autocorrelation principle that recognizes that data collected at any position will have a great similarity to, or influence of those locations within its immediate vicinity.

Digital elevation models , triangulated irregular networks , edge-finding algorithms, Thiessen polygons , Fourier analysis , (weighted) moving averages , inverse distance weighting , kriging , spline , and surface analysis are all mathematical methods to produce interpolative data.

Address geocoding

Geocoding is interpolating spatial locations (X, Y coordinates) ZIP codes , parcel lots and address locations. A reference theme is required to geocodeindividual addresses, such as a road centerline file with address ranges. The individual addresses have historically been interpolated, or estimated, by examining the addresses along a road segment. These are usually provided in the form of a table or database. The software will then place a dot where the address belongs to the segment of centerline. For example, an address point of 500 will be at the midpoint of a line that starts with. Geocoding can also be applied against actual data, typically from municipal tax maps. In this case, the result of the geocoding will be an opportunity for an interpolated point. This approach is more widely used.

Reverse geocoding

Reverse geocoding is the process of returning year Estimated street address number as it concerne un Given coordinate. For example, a user can click on a road centerline theme. This house number is interpolated from a range assigned to that road segment. If the user clicks at the midpoint of a segment that starts with 100, the return value will be somewhere near 50. Note that reverse geocoding tidy.

Multi-criteria decision analysis

Coupled with GIS, a multi-criteria decision analysis method for decision-makers in an alternative spatial solution, such as the most likely ecological habitat for restoration, against multiple criteria, such as vegetation cover or roads. MCDA uses decision rules to aggregate the criteria, which allows the alternative solutions to be ranked or prioritized. ^[32] GIS MCDA may reduce costs and time.

Data output and cartography

Cartography is the design and production of maps, or visual representations of spatial data. The vast majority of modern cartography is done with the help of computers, usually using GIS but production of quality cartography is also achieved by importing layers into a design program to refine it. Most GIS software gives the user substantial control over the appearance of the data.

Cartographic work serves two major functions:

First, it produces graphics on the screen or on paper that convey the results of analysis to the people who make decisions about resources. Wall maps and other graphics can be generated, allowing the viewer to visualize and understand the results of analyzes or simulations of potential events. Web Map Servers using web-based application programming interfaces ( AJAX , Java , Flash , etc.).

Second, other database information can be generated for further analysis or use. An example would be a list of all addresses within one mile (1.6 km) of a toxic spill.

Graphic display techniques

Traditional maps are abstractions of the real world, a sampling of important elements. People who use maps must interpret these symbols. Topographic maps show the shape of land area with the contour lines or with shaded terrain .

Today, graphic display techniques, such as shading based on altitude in a GIS can make relationships among visible elements, heightening one’s ability to extract and analyze information. For example, two types of data are combined in a GIS to produce a perspective view of a portion of San Mateo County , California .

• The digital elevation model , consisting of surface elevations recorded on a 30-meter horizontal grid, shows high elevations as white and low elevation as black.
• The accompanying Landsat Thematic Mapper image shows a false-color infrared image looking down at the same area in 30-meter pixels, or picture elements, for the same coordinate points, pixel by pixel, as the elevation information.

A GIS was used to register and combine the two images to render the three-dimensional perspective view of the San Andreas Fault , using the Thematic Mapper image pixels, but shaded using the elevation of the landforms . The GIS display depends on the view of the observer and the time of day, to properly render the shadows created by the sun’s rays at that latitude, longitude, and time of day.

An archeochrome is a new way of displaying spatial data. It is a thematic on a 3D map that is applied to a specific building or a part of a building. It is adapted to the visual display of heat-loss data.

Spatial ETL

Spatial ETL tools provide the data processing functionality of traditional extract, transform, load (ETL) software, but with a primary focus on the ability to manage spatial data. They provide GIS users with the ability to translate the data into different formats, while geometrically transforming the data en route. These tools can come in the form of add-ins to existing wider-purpose software such as spreadsheets .

GIS data mining

GIS or spatial data mining is the application of data mining methods to spatial data. Data mining, which is the most widely used automated search for hidden models, offers great potential benefits for applied GIS-based decision making. Typical applications include environmental monitoring. A characteristic of such applications is that spatial correlation between data measurements require the use of specialized algorithms for more efficient data analysis. ^[33]

Applications

The implementation of a GIS is often driven by jurisdictional (such as a city), purpose, or application requirements. Generally, a GIS implementation can be custom-designed for an organization. Hence, a GIS deployment developed for an application, jurisdiction, enterprise, may not be necessarily interoperable or compatible with a jurisdiction, enterprise, or purpose. ^{[ quote needed ]}

GIS provides, for every kind of location-based organization, a platform to update and a database manually. When integrated with other GIS Powerful enterprise solutions like SAP ^[34] and the Save Wolfram ^[35] helps Creating Powerful decision support system at enterprise level. ^{[36] [ clarification needed ]}

Many disciplines can benefit from GIS technology. An active GIS market in the hardware and software components of GIS, and use in the fields of science, government, business , and industry , with applications including real estate , public health , crime mapping , national defense , sustainable development , natural resources , climatology, ^[37] [38] landscape architecture , archeology , regional and community planning, transportation and logistics. GIS is also diverging intolocation-based services , which allows GPS-enabled mobile devices to display their location in close relation to fixed objects (nearest restaurant, gas station, fire hydrant) or mobile objects (friends, children, police car), or to relay their position back to a central server for display or other processing.

Open Geospatial Consortium standards

The Open Geospatial Consortium (OGC) is an international industry consortium of 384 companies, government agencies, universities, and others participating in a consensus process. OpenSIGLE Interfaces with Interoperable Solutions that “geo-enable” the Web, wireless and location-based services, and mainstream IT, and empowering technologies . Open Geospatial Consortium protocols include Web Map Service , and Web Feature Service . ^[39]

GIS products are broken down by the OGC into two categories, based on OGC specifications.

Compliant Products are software products that comply with OGC’s OpenGIS Specifications. When tested by the OGC Testing Program, the product is automatically registered as “compliant” on this site.

Implementing Products are software products that implement OpenGIS Specifications. Compliance tests are not available for all specifications. OGC reserves the right to review and verify each entry.

Web mapping

In recent years there has-been a proliferation of free-to-use mapping software and Easily accessed Such As the proprietary web application Google Maps and Bing Maps , as well as the free and open-source alternative OpenStreetMap . These services give the public access to the largest amounts of geographic data; perceived by many users to be trustworthy and useful as professional information. ^[40]

Some of them, like Google Maps and OpenLayers , expose an application programming interface (API) that enables users to create custom applications. These tools are commonly offered by street maps, aerial / satellite imagery, geocoding, searches, and routing functionality. Web mapping has also uncovered the potential of crowdsourcing geodata in projects like OpenStreetMap , which is a collaborative project to create a free editable map of the world. These mashup projects have been made to provide a high level of value and benefit to users through traditional geographic information. ^[41] [42]

Adding the dimension of time

The condition of the Earth ‘s surface, atmosphere, and subsurface can be examined by feeding satellite data into GIS. GIS technology gives researchers the ability to examine the variations in Earth processes over days, months, and years. As an example, the changes in vegetation vigor through a growing season. The resulting graphic represents a rough measure of plant health. Working with two variables over time would then allow to detect regional differences in the lag between a decline in rainfall and its effect on vegetation.

GIS technology and the availability of such data. The satellite sensor output is used for generating a high resolution (AVHRR). This sensor system detects the amounts of energy in the Earth’s surface. The satellite sensor produces images of a particular location on Earth twice a day. AVHRR and more recently the moderate-resolution imaging spectroradiometer (MODIS) are only two of many sensor systems used for Earth surface analysis.

In addition to the integration of time in environmental studies, GIS is also being explored for its ability to track the progress of humans throughout their daily routines. A concrete example of progress in this area is the recent release of time-specific population data by the US Census . In this data set, the populations of cities are shown for daytime and evening hours highlighting the pattern of concentration and dispersion generated by North American commuting patterns. The manipulation and generation of data required to produce this data would have been possible without GIS.

Using models to project the data Held by a GIS forward in time-have enabled planners to test policy decisions using spatial decision support systems .

Semantics

Tools and technologies emerging from the World Wide Web Consortium ‘s Semantic Web are proving Useful for data integration problems in information systems. Correspondingly, such technologies have been proposed as a means to facilitate interoperability and data reuse among GIS applications. ^[43] [44] and also to enable new analysis mechanisms. ^[45]

Ontologies are a key component of this semantic approach, they are a formal, machine-readable specification of the concepts and relationships in a given domain. This in turn allows GIS to focus on the meaning of data rather than its syntax or structure. For example, reasoning That a land cover types classified as deciduous needleleaf trees in one dataset is a specialization or subset of land cover types forest in Reviews another more Roughly classified dataset can help a GIS automatically merge the two datasets under the more general land cover classification. Attempts have been developed in GIS applications, for example hydrology ontology ^[46]developed by the Ordnance Survey in the United Kingdom and the SWEET ontologies ^[47] developed by NASA ‘s Jet Propulsion Laboratory . Also, simpler ontologies and semantic metadata are proposed by the W3C Geo Incubator Group ^[48] to represent geospatial data on the web. GeoSPARQL is a standard developed by the Ordnance Survey, United States Geological Survey , Natural Resources Canada , Australia’s Commonwealth Scientific and Industrial Research Organizationand others to support OGC literals (GML, WKT), topological relationships (Simple Features, RCC8, DE-9IM), RDF and the SPARQL database query protocols.

Recent research results in this area can be seen in the International Conference on Geospatial Semantics ^[49] and the Terra Cognita – Directions to the Geospatial Semantic Web ^[50] workshop at the International Semantic Web Conference.

Implications of GIS in society

With the popularization of GIS in decision making, scholars have begun to voteize the social and political implications of GIS. ^{[51] [52] [53]} GIS can also be misused to distort reality for individual and political gain. ^[54] [55] It has-been argued que la production, distribution, utilization, and representation of geographic information are Largely related with the social context and the potential HAS pour augmenter citizen trust in government. ^[56] Other related topics include discussion on copyright , privacy , and censorship . A more optimistic social approach to GIS adoption is a tool for public participation.

GIS in education

At the end of the 20th century, GIS was discovered in the classroom. ^[57] The benefits of GIS in education seems focused on developing spatial thinking , but it is not enough in the literature to show the reality of GIS in education around the world where the curriculum mentions them. ^[58] : 36

GIS sccm to Provide Many advantages in teaching geography Because They allow for analyzes based are real geographic data and aussi help raise Many research issues from teachers and students in classrooms, as well As They contribuer to improvement in learning by Space Developing and geographical thinking and, in many cases, student motivation. ^[58] : 38

GIS in local government

GIS is an organization-wide, enterprise and enduring technology that continues to operate locally. ^[59] Government agencies have adopted GIS technology

• Public Safety ^[60] operations such as Emergency Operations Centers, Fire Prevention, Police and Sheriff’s mobile technology and dispatch, and mapping weather risks.
• Parks and Recreation departments and their functions in asset inventory, land conservation, land management, and cemetery management.
• Public Works and Utilities, water and stormwater drainage, electrical assets, engineering projects, and public transportation assets and trends.
• Fiber Network Management for interdepartmental network assets
• School of analytical and demographic data, asset management, and improvement / expansion planning
• Public Administration for Election Data, Property Records, and Zoning / Management.

The Open Data initiative is pushing local government to take advantage of technology such as GIS technology, as it encompasses the requirements of the Open Data / Open Government Model of Transparency. ^[59] With Open Data, local government organizations can implement Citizen Engagement applications and online portals, allow citizens to see information, report potholes and signage issues much more. ^[61] [62] GIS technology spending, and database management is the driving force behind GIS technology spending.