Changes between Version 7 and Version 8 of WKTRaster/FAQ


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Timestamp:
Feb 25, 2010, 2:34:23 PM (14 years ago)
Author:
pracine
Comment:

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  • WKTRaster/FAQ

    v7 v8  
    2020'''4 - Why does every tile is georeferenced?'''
    2121
     22In a traditional raster system only the global image is georeferenced. The system assume that the sum of tiles form a perfect rectangle well aligned on a grid. This is the raster view of geospatial data. However the reality is often different. People use raster data on area which are not necessarily rectangle. This is the coverage view of raster geospatial data. Having one georeference per tile allow WKT Raster to store raster coverage which are not necessarily rectangular.
     23
     24They also often need to convert vector data to raster data in order to perform certain operations. If you convert a vector coverage containing gaps or overlaps to raster, you may result in way too much information or in a lost of information. In WKT Raster each vector object convert to a single raster. Having one georeference per tile (or raster) is very usefull to accomplish this goal.
     25
    2226'''5 - How come it is possible to store overlapping rasters in the same table? In a raster, tiles should not overlaps.'''
    2327