seadas 8.4.1 reprojection of MODIS images using gpt found different products than those obtained directly using the GUI
Posted: Wed May 14, 2025 7:16 am America/New_York
Reprojection of MODIS products using SeaDAS 8.4.1 revealed discrepancies in the products generated using the GUI generation HO gpt. When confronted with an image spanning 180° of longitude, the product generated using gpt is missing a portion, whereas the product generated directly using the GUI does not.
The gpt code I use:
gpt ReprojectGraphEx01.xml -p ReprojectEx01.par -Pifile="!infile!" -Pofile="!outfile!"
ReprojectGraphEx01.xml is:
<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>${ofile}</file>
<formatName>NetCDF4-CF</formatName>
</parameters>
</node>
</graph>
ReprojectEx01.par is :
pixelSize=0.009
resampling=Nearest
The individual parameters I selected in the GUI interface are:
CRS：Custom CRS Projection:Geographic Lat/Lon (WGS 84)
Resolution： Easting ，Northing ，Orientation are default， Pixel SizeX and SizeY are 0.009
Resampling method：Nearest
No-data value ： NAN
“Reproject tie-point grids” is checked.
computer operating system：Windows 11
The gpt code I use:
gpt ReprojectGraphEx01.xml -p ReprojectEx01.par -Pifile="!infile!" -Pofile="!outfile!"
ReprojectGraphEx01.xml is:
<graph id="ReprojectGeoLatLonGraph">
<version>1.0</version>
<node id="Read">
<operator>Read</operator>
<sources/>
<parameters class="com.bc.ceres.binding.dom.XppDomElement">
<file>${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>
ReprojectEx01.par is :
pixelSize=0.009
resampling=Nearest
The individual parameters I selected in the GUI interface are:
CRS：Custom CRS Projection:Geographic Lat/Lon (WGS 84)
Resolution： Easting ，Northing ，Orientation are default， Pixel SizeX and SizeY are 0.009
Resampling method：Nearest
No-data value ： NAN
“Reproject tie-point grids” is checked.
computer operating system：Windows 11