Geographic Information System (GIS)

A system to capture, store, analyze and manage data and associated attributes that are spatially referenced to the Earth. The system allows users to represent on data on maps, create interactive queries, analyze the spatial information, edit data, maps, and present the results of all these operations.

Applications

GIS in the Telematics space can be used for In-vehicle navigation, represent position of mobile and fixed assets on maps, routing, asset management, address geo-coding and reverse geo-coding. Other applications include scientific investigations, resource management, asset management, environmental impact assessment, urban planning, cartography, criminology, and history.

GIS Software

GIS includes creation, representation and capture of data, raster to vector translation, Projection, Coordinate system & Registration, Spatial Analysis, Data Output & Cartography, Graphic display Techniques and Spatial ETL. Once GIS data information is created using numerous GIS software available information can be accessed, transferred, transformed, overlaid, processed and displayed. Within industry commercial offerings from companies such as ESRI and Mapinfo dominate, offering an entire suite of tools. Government and military departments often use custom software, open source products, such as GRASS, or more specialized products that meet a well defined need. Although free tools exist to view GIS datasets, public access to geographic information is dominated by online resources such as Google Earth and interactive web mapping. The applications of GIS software are described below,

GIS Processing Software - Is used for the task of preparing data for use within a GIS. This transforms the raw or legacy geographic data into a format usable by GIS products.

Geo-Databases - A database with extensions for storing, querying, and manipulating geographic information and spatial data.

Management and Analysis - GIS analysis software takes GIS data and overlays or otherwise combines it so that the data can be visually analyzed and output a detailed map or image. The software performs transformation on raster and vector data sometimes of differing datums, grid system, or reference system, into one coherent image. This software is central to the professional analysis and presentaton of GIS data. Examples include the ArcGIS family of ESRI GIS applications (which replaced ESRI's older Arc/INFO), Smallworld, XMap and GRASS.

Statistical - GIS statistical software uses standard database queries to retrieve data and analyse data for decision making.

Readers - GIS readers are computer applications that are designed to allow users to easily view digital maps as well as view and query GIS-managed data.

Web API - GIS APIs are designed to manage GIS data for its delivery to a web browser client from a GIS server. They are accessed with commonly used scripting language such as VBA or JavaScript. They are used to build a server system for the delivery of GIS that is to made available over an intranet or publicly over the Internet.

Mobile GIS - GIS has seen many implementations on mobile devices. With the widespread adoption of GPS, GIS has been used to capture and integrate data in the field.

Free and Open-Source GIS Software - Many GIS tasks can be accomplished with free or open-source software. Well-known open source GIS software includes GRASS GIS, Quantum GIS, MapServer, uDig, OpenJUMP, gvSIG and many others (e.g., see OSGeo or MapTools).

Vehicle Navigation - A database model of a network of roads and related features is a form of GIS data that is used for vehicle navigation systems. An Automotive navigation system will combine map-matching, GPS coordinates, and Dead reckoning to estimate the position of the vehicle. The map database is also used for route planning and guidance, and possibly advanced functions involving active safety, driver assistance and location-based services.

GIS Data

Data Creation and Capture - Modern GIS technologies use digital information, for which various digitized data creation methods are used. The most common method of data creation is digitization and heads up digitization. Entering information into the system consumes much of the time of GIS practitioners. There are a variety of methods used to enter data into a GIS where it is stored in a digital format. Existing data printed on Paper, PET film maps, Survey data, Remote sensed data, Aerial photographs, Satellite remote sensing etc form the data source for GIS. These can be digitized, scanned or directly entered into via digital data collection systems depending on the data source type. Depending on the user the data is captured with either a relative accuracy or absolute accuracy, since this influence how information will be interpreted and the cost of data capture. In addition to collecting and entering spatial data, attribute data is also entered into a GIS. For vector data, this includes additional information about the objects represented in the system. After entering data into a GIS, the data usually requires editing, to remove errors, or further processing.

Data Representation - GIS data represents real world objects such as roads, land use, elevation with digital data. There are two broad methods used to store data in a GIS for Raster and Vector abstractions. Geographical features are often expressed as vectors, by considering those features as geometrical shapes. In the popular ESRI Arc series of programs, these are explicitly called shapefiles. Different geographical features are best expressed by different types of geometry:

  Points - Zero-dimensional points are used for simple location such as the locations of point
    of interest such as buildings, parks etc.

  Lines or polylines - One-dimensional lines or polylines are used for linear features such as
    rivers, roads, railroads, trails, and topographic lines.

  Polygons - Two-dimensional polygons are used for geographical features that cover a
    particular area of the earth's surface. Such features may include lakes, park boundaries,
    buildings, city boundaries, or land uses. Each of these geometries are linked to a row in a
    database that describes their attributes.

Projection and Coordinate System - Before the digital data can be analyzed, they may have to undergo other manipulations. A projection is a mathematical means of transferring information from a model of the Earth, which represents a three-dimensional curved surface, to a two-dimensional medium-paper or a computer screen.

Spatial Analysis - This involves Data modeling, Topological modeling, Networks, Cartographic modeling, Map overlay, Automated cartography, Geo-statistics, Address Geo-coding and Reverse Geo-coding.

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 using GIS software.