Inquiry about the reprojection function of seadas GUI and gpt comand line
Posted: Wed May 14, 2025 7:02 am America/New_York
Hello, when I used the SeaDAS GUI and the GPT command line to process a L2 MODIS image (AQUA_MODIS.20030930T013001.L2.OC.nc), I found that the projection chla images by the two methods are different (following figures). When I checked the settings of the two methods, I didn't find the difference in the key parameters, and I have tried different versions of SeaDAS, but this problem still cannot be solved. Since I need to batch process the L2 images near the Bering Sea, the GPT method is more in line with my needs. However, currently, it seems that there are some defects in this method. The following is the parameter setting method of my Graphs. I'm not sure if there is something wrong with my parameter setting. or maybe there are other ways to carry out the projection work in batches? Thanks for your help.
<graph id="ReprojectGeoLatLonGraph">
<version>1.0</version>
<node id="Read">
<operator>Read</operator>
<sources/>
<parameters class="com.bc.ceres.binding.dom.XppDomElement">
<file>${ifile}</file>
<formatName>SeaDAS-L2</formatName>
</parameters>
</node>
<node id="Reproject">
<operator>Reproject</operator>
<sources>
<sourceProduct refid="Read"/>
</sources>
<parameters class="com.bc.ceres.binding.dom.XppDomElement">
<wktFile/>
<crs>
GEOGCS["WGS84(DD)",
DATUM["WGS84",
SPHEROID["WGS84", 6378137.0, 298.257223563]],
PRIMEM["Greenwich", 0.0],
UNIT["degree", 0.017453292519943295],
AXIS["Geodetic longitude", EAST],
AXIS["Geodetic latitude", NORTH]]
</crs>
<resampling>${resampling}</resampling>
<orientation>0.0</orientation>
<pixelSizeX>${pixelSize}</pixelSizeX>
<pixelSizeY>${pixelSize}</pixelSizeY>
<orthorectify>false</orthorectify>
<noDataValue>NaN</noDataValue>
<includeTiePointGrids>true</includeTiePointGrids>
<addDeltaBands>false</addDeltaBands>
</parameters>
</node>
<node id="Write">
<operator>Write</operator>
<sources>
<sourceProduct refid="Reproject"/>
</sources>
<parameters class="com.bc.ceres.binding.dom.XppDomElement">
<file>${ofile}</file>
<formatName>NetCDF4-CF</formatName>
</parameters>
</node>
</graph>
<graph id="ReprojectGeoLatLonGraph">
<version>1.0</version>
<node id="Read">
<operator>Read</operator>
<sources/>
<parameters class="com.bc.ceres.binding.dom.XppDomElement">
<file>${ifile}</file>
<formatName>SeaDAS-L2</formatName>
</parameters>
</node>
<node id="Reproject">
<operator>Reproject</operator>
<sources>
<sourceProduct refid="Read"/>
</sources>
<parameters class="com.bc.ceres.binding.dom.XppDomElement">
<wktFile/>
<crs>
GEOGCS["WGS84(DD)",
DATUM["WGS84",
SPHEROID["WGS84", 6378137.0, 298.257223563]],
PRIMEM["Greenwich", 0.0],
UNIT["degree", 0.017453292519943295],
AXIS["Geodetic longitude", EAST],
AXIS["Geodetic latitude", NORTH]]
</crs>
<resampling>${resampling}</resampling>
<orientation>0.0</orientation>
<pixelSizeX>${pixelSize}</pixelSizeX>
<pixelSizeY>${pixelSize}</pixelSizeY>
<orthorectify>false</orthorectify>
<noDataValue>NaN</noDataValue>
<includeTiePointGrids>true</includeTiePointGrids>
<addDeltaBands>false</addDeltaBands>
</parameters>
</node>
<node id="Write">
<operator>Write</operator>
<sources>
<sourceProduct refid="Reproject"/>
</sources>
<parameters class="com.bc.ceres.binding.dom.XppDomElement">
<file>${ofile}</file>
<formatName>NetCDF4-CF</formatName>
</parameters>
</node>
</graph>