Can a land use map be related to a satellite image, a timely indicator of land use? Yes, but because digital data are collected and stored in different ways, the two data sources may not be entirely compatible. Therefore, a GIS must be able to convert data from one structure to another.
The Data acquisition stage collects raw imagery data that is redundant & needs to be stitched together into a more apt data stream.
ATPL’s Pre processing involves digitization of the acquired data that includes:
- 3D data processing- Creating realistic models of buildings and structures by visualizing them in 3-Dimensional environment is termed as 3D data processing. Roof detail and elevation details of building or structure are truly represented in this process.
- Value addition to Image data for large scale mapping- In order to transfer the spatial components from images to maps, it is essential to have accurate base maps on large scales. It is necessary to generate large scale base maps for use in various thematic applications.
Large scale mapping needs the following components:
- » Sources of Data Acquisition
- » Data content and its accuracy
- » Map projection
- » Spatial extents
GIS can be used to depict two- and three-dimensional characteristics of the Earth's surface, subsurface, and atmosphere from points where samples have been collected. GIS makes it possible to link, or integrate, information that is difficult to associate through any other means.
Thus, a GIS can use combinations of mapped variables to build and analyze new variables.