About Spatial Data And Standard GIS Formats
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Standard GIS Formats are the structures that are utilized for storing data in a GIS file. Spatial data is a predominant type of data that is stored in standard GIS Formats. Spatial Data refers to the location and characteristics or attributes of a geographic feature that is normally stored as topology and specific coordinates. Specific geographic features can then be viewed as illustrative and descriptive information. Spatial Data is available in many forms such as aerial photography, digital maps, paper maps, and digital satellite images. When transferred or stored in a standard GIS format, the data can then be viewed and manipulated according to the user's particular purpose. There are a number of GIS formats that can be used for mapping spatial data and they include:
Vector Formats: Vector Data represents geographic features as x and y coordinates or X, Y, Z triples, using the coordinate system marked out for the map. Features are described as Lines (two or more points in a specific sequence,) Points a (single pair of coordinates,) and polygons (an area enclosed by a line). A large number of GIS applications are based on vector technology. Vector formats are the most common formats because they allow for numerous ways to store coordinates, database structures, a particular location's attributes, and then display the information in a readable and descriptive format. Examples of common vector formats are DXF and Shape, Mapinfo MiD/MiF files, and arc/info Export (E00 files).
Raster Formats: Raster data is a pixel or cell based means of displaying the earth's features. Each cell or pixel will have a specific value. Images or maps created by scanning as well as satellite images are examples of raster data. For the most part, raster files are involved in image information storage, satellite captured information, and other above ground imaging systems. The systems where these images are captured and stored are called remote-sensing data. Resolution is given in meters in which each cell represents the size of the surface area being covered. Examples of raster formats include: JpEG, TiFF, BMp and GiF.
Some common raster formats include:
Digital Elevation Model (DEM): Often used to document elevation data, DEM cells represent the elevations of points on the earth's surface.
Spatial Data Transfer Standard (SDTS): SDTS is designed to transfer geographic information.
It is important to note that some digital maps do not contain all types of information. For example, raster maps usually do not include attribute information which is additional non-graphic information about each feature, and many vector data sources do not include display information, which describes how the features will appear on the screen. If you have complex data requirements, you will want to learn about a broader range of transfer formats, especially if you want to blend Spatial data from different sources. Fortunately, there are companies that specialize in placing complex formats into Standard GIS format so that you will be able to comprehend the different types of data in your map and then use it according to your specific project needs.
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