![]() MrSID and JPEG2000 are supported out of the box by ArcPad whereas ECW requires a 3rd party extension downloadable from ERMapper's website. They are fast when viewing the overall image but may slow down when you zoom in since higher detailed tiles are being retrieved and decompressed which consumes more memory and more CPU time. MrSID, JPEG2000 and ECW are hierarchical tile formats. This is because when JPEGs are loaded into ArcPad they are decompressed in their entirety and can consume large amounts of memory. JPEGs should be used for small photos like 1 mega pixel images. If you inadvertently choose a lossy compression for a cartographic map the edges of lines will distort noticeably producing a poorer looking map. scan images, digital camera photos and aerial photography) otherwise choose a non lossy compression for computer generated images such as a cartographic map. Choose lossy compression for captured imagery (e.g. They achieve high 20:1 compression by losing/replacing bits of image often undetected by the human eye. You may get different results which could and should affect your choice of raster format. ![]() You should always check by running your own performance tests on your data. In the table Compression, Memory and Drawing speed are a rough guide based on my personal experience. To make a proper raster format choice, you should read the entire blog entry, however, having said that, my favourite is TIFF/ LZW because it is every where, it has a good compression (10:1), uses little memory and is fast. ![]()
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