Changes between Version 9 and Version 10 of WKTRaster/FAQ


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Timestamp:
Mar 22, 2010, 11:13:20 AM (14 years ago)
Author:
pracine
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  • WKTRaster/FAQ

    v9 v10  
    2020'''4 - Why does every tile is georeferenced?'''
    2121
    22 In 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.
     22In a traditional raster system only the global image is georeferenced, not every tile. The system assume that the area covered by the tiles forms 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 covering area for which the sum of the tiles do not necessarily result in a 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.
    2323
    2424They 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 properly support this feature.