Changes between Version 22 and Version 23 of FAQRaster


Ignore:
Timestamp:
Jan 12, 2010, 3:19:43 PM (14 years ago)
Author:
maphew
Comment:

palette example and cite source

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  • FAQRaster

    v22 v23  
    144144
    145145
    146 == Create or Edit Color Palette ==
     146== How to create or modify an image color table ? ==
    147147
    148 ''What is the easiest way to create or edit a color table in an image?''
     148The easiest non-scripting way to create or modify a color palette is to translate your file to VRT (XML) format, and edit the color table in the XML file.
     149{{{
     150# create the vrt
     151gdal_translate -of VRT your.tif your.vrt
    149152
    150 The easiest non-scripting way to do this is to translate your file to VRT (XML) format, and edit the color table in the XML file. eg.
    151 {{{
    152 gdal_translate -of VRT your.tif your.vrt
    153 }}}
    154 edit `your.vrt` and modify the color table, see [http://www.gdal.org/gdal_vrttut.html Virtual Format Tutorial] for detailed syntax options. Then
    155 {{{
     153## --- edit colour table here ---
     154
     155# create final fixed image
    156156gdal_translate your.vrt your_fixedup.tif
    157157}}}
    158 Note that the .vrt file doesn't actually include the image data, it just references back to your.tif (or other supported format).
    159158
    160 This general approach can be used to modify metadata, color tables, gcps and other things for which there is no easy to do set them with gdal_translate. There are other mechanisms to do this via scripting or c/c++ programming.
     159The .vrt file doesn't actually include the image data, it just references back to your.tif (or other supported format). This general approach can be used to modify metadata, color tables, gcps and other things for which there is no easy to do set them with gdal_translate. There are other mechanisms to do this via scripting or c/c++ programming.
    161160
     161Here is an example for [http://topomaps.usgs.gov/drg/ USGS DRGs], see [http://www.gdal.org/gdal_vrttut.html Virtual Format Tutorial] for detailed syntax options. The entries are in palette order and correspond to red, green, blue & alpha channels.
     162{{{
     163<ColorInterp>Palette</ColorInterp>
     164<ColorTable>
     165        <Entry c1="0" c2="0" c3="0" c4="255"/>
     166        <Entry c1="255" c2="255" c3="255" c4="255"/>
     167        <Entry c1="0" c2="151" c3="164" c4="255"/>
     168        <Entry c1="203" c2="0" c3="23" c4="255"/>
     169        <Entry c1="131" c2="66" c3="37" c4="255"/>
     170        <Entry c1="201" c2="234" c3="157" c4="255"/>
     171        <Entry c1="137" c2="51" c3="128" c4="255"/>
     172        <Entry c1="255" c2="234" c3="0" c4="255"/>
     173        <Entry c1="167" c2="226" c3="226" c4="255"/>
     174        <Entry c1="255" c2="184" c3="184" c4="255"/>
     175        <Entry c1="218" c2="179" c3="214" c4="255"/>
     176        <Entry c1="209" c2="209" c3="209" c4="255"/>
     177        <Entry c1="207" c2="164" c3="142" c4="255"/>
     178</ColorTable>
     179}}}
     180
     181^Source: http://n2.nabble.com/simplest-method-for-creating-editing-a-GTiff-color-table-td2030656.html#a2030656 .^