artemp/trac2github — Issue #503: Map buffer_size not accounted for within GDAL plugin scaling logic
Author: artemp
Created: 2011-10-09 20:37:37+00:00
State: open
Labels: GDAL_Input_Driver

Near the scale where we reach the resolution limits of an input raster we avoid having GDAL pre-scale the image, so that upsampling can be done within the RasterSymbolizer.

This is currently done here: http://trac.mapnik.org/browser/trunk/plugins/input/gdal/gdal_featureset.cpp#L139

But when map buffers are used it is likely that`im_width != width` is at, or past, the resolution limit of the image and a GDAL pre-scaled image is chosen that is too small.