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dev:gdal [2011/12/09 15:42]
admin [GDAL Limitations]
dev:gdal [2011/12/16 14:03]
admin [GDAL Limitations]
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 | SAGA | .sdat | | SAGA | .sdat |
  
-<​note>​ +Some important notes: 
-  * The support to AAIGrid (.asc) in GDAL is read only. So, Dinamica EGO provides the writing capability itself. This format can read and write images using [[:Cell Type Type|cell types]] "​Signed 32 Bit Integer"​ and "IEEE 754 32 Bit Real"​. ​The cell type is detected ​automatically.+ 
 +  * The support to AAIGrid (.asc) in GDAL is read only. So, Dinamica EGO provides the writing capability itself. This format can read images using [[:Cell Type Type|cell types]] "​Signed 32 Bit Integer"​ and "IEEE 754 32 Bit Real"​. ​All cell types can be written, but they are automatically ​converted back to one of those formats next time Dinamica reads the image again.
  
   * The support to ERMapper (.ers) in GDAL ignores class names. To workaround this limitation, support to reading and writing this file format is provided by Dinamica EGO itself.   * The support to ERMapper (.ers) in GDAL ignores class names. To workaround this limitation, support to reading and writing this file format is provided by Dinamica EGO itself.
-</​note>​ 
  
 ==== GDAL Limitations ==== ==== GDAL Limitations ====
  
-GDAL (and some times the underlying file format) imposes limitations on the representation of projections,​ category names and their corresponding colors. The limitations and their corresponding workaround are listed in the table below:+GDAL (and some times the underlying file format) imposes limitations on the representation of projections,​ category namestheir corresponding colors ​and layer names. The limitations and their corresponding workaround are listed in the table below:
  
 ^ Limitation ^ Workaround ^  ^ Limitation ^ Workaround ^ 
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 | Several file formats do not support the storage of category names. ​ | To workaround this limitations,​ it is possible to use a VRT file or an auxiliary PAM XML file to keep this information. The ERMapper file format has the best support to category names and colors. ​ | | Several file formats do not support the storage of category names. ​ | To workaround this limitations,​ it is possible to use a VRT file or an auxiliary PAM XML file to keep this information. The ERMapper file format has the best support to category names and colors. ​ |
 | Several file formats do not support the storage of category colors. ​ | To workaround this limitations,​ it is possible to use a VRT file or an auxiliary PAM XML file to keep this information. The ERMapper file format has the best support to category names and colors. ​ | | Several file formats do not support the storage of category colors. ​ | To workaround this limitations,​ it is possible to use a VRT file or an auxiliary PAM XML file to keep this information. The ERMapper file format has the best support to category names and colors. ​ |
-| The categories must start from 0 and their definition must be contiguous. ​ | Unfortunately,​ the only way to workaround this limitation is defining dummy categories or using the ERMapper file format. ​ |+| Several file formats do not support the storage of layer names. ​ | To workaround this limitations,​ it is possible to use a VRT file or an auxiliary PAM XML file to keep this information. The ERMapper file format also has support to layer names. ​ | 
 +| The categories must start from 0 and their definition must be contiguous. ​ | Unfortunately,​ the only way to workaround this limitation is defining dummy categories ​(Dinamica does this when representing non-contiguous categories in a GDAL supported format) ​or using the ERMapper file format. ​ |
  
 ==== Dinamica Limitation ==== ==== Dinamica Limitation ====
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 ===== Virtual Format ===== ===== Virtual Format =====
  
-GDAL support a virtual file format called [[http://​www.gdal.org/​gdal_vrttut.html|VRT]]. This format can be used to transform an image defining a different registration info, different classe names and a different color table. A example of a VRT file defined from a two unrelated image files can be found below.+GDAL support a virtual file format called [[http://​www.gdal.org/​gdal_vrttut.html|VRT]]. This format can be used to transform an image defining a different registration info, different classe names and a different color table. It can also be use to create mosaics from several different images. A example of a VRT file defined from a two unrelated image files can be found below.
  
 <file xml test.vrt>​ <file xml test.vrt>​
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 </​VRTDataset>​ </​VRTDataset>​
 </​file>  ​ </​file>  ​
 +
 +===== PAM XML Auxiliary File =====
 +
 +!!!FIXME