Ticket #3837 (closed defect: fixed)
AREA_OR_POINT=Point is ignored in georeferencing
| Reported by: | rhijmans | Owned by: | warmerdam |
|---|---|---|---|
| Priority: | high | Milestone: | |
| Component: | GDAL_Raster | Version: | unspecified |
| Severity: | major | Keywords: | AREA_OR_POINT gtiff |
| Cc: |
Description
GDAL docs ( http://www.gdal.org/gdal_datamodel.html ) say:
The following metadata items have well defined semantics in the default domain: AREA_OR_POINT: May be either "Area" (the default) or "Point". Indicates whether a pixel value should be assumed to represent a sampling over the region of the pixel or a point sample at the center of the pixel. This is not intended to influence interpretation of georeferencing which remains area oriented.
AREA_OR_POINT=Point appears in geotiff files produced by the HEG-Modis Reprojection Tool. Presumably these files use the flag "PixelIsPoint?" mentioned in the geoTiff docs ( http://www.remotesensing.org/geotiff/spec/geotiff2.5.html ).
These geotiff docs say that "PixelIsArea?" and "PixelIsPoint?" _do_ have implications for georeferencing (that's the point).
It appears that gdalinfo indeed ignores this flag. And it seems to me that this is wrong. Or does gdal do adjustments "under the hood"?
In contrast, it seems that ArcMap? 9.3 does not ignore it (although it seems to make a mistake in how it corrects for it)
