ASTER User's Guide - NASA

ASTER Users HandbookOuter G-RingHoleGPolygonInner G-RingPointsFigure 31: G-Ring and G-Polygon.What is the difference between the GRing coordinates in the .met file versus those specifiedfor the SCENEFOURCORNERS in the embedded metadata of the hdf file?The GRing coordinates are populated by ECS using the SCENEFOURCORNERS informationfrom the embedded metadata in the hdf file. The only difference is that G-Ring coordinates arerounded till the fourth decimal place while the SCENEFOURCORNERS have up to six decimalplaces.Where would I find the projection information within the metadata?This information is present under “Processing Parameters” in the product metadata for eachsensor within the embedded metadata of an ASTER Level-1B granule. It includes the followingattributes: Map projection, Projection parameters, Zonecode, Resampling method, Correction ofinter-telescope error (for SWIR & TIR), and Correction of SWIR parallax error.Where would I find the datum information within the metadata?Currently, the datum information is not carried by the metadata. It is recommended that you useNAD1983 for the continental United States and WGS1984 for the rest of the world.Are the pixel coordinates referenced by the upper left corner of the pixel or the center ofthat pixel?The pixel coordinates are referenced by the center of that pixel.Do the SCENEFOURCORNERS reference the corners of the image or those of the file?78