[GRASS-user] Re: link to datasets from other locations?

Nikos Alexandris nikos.alexandris at felis.uni-freiburg.de
Thu Jul 2 05:00:58 EDT 2009


> *every* single GIS I have seen which does on-the-fly reprojection has
> had major problems which can present itself in a way which is not
> obvious to the user (typically due to mixed datums).

> Then the user happily goes along doing their work, publishing their
> reports, only sometimes realizing that something has misaligned
> internally.

> Or ugly non-solutions like rubber sheet dragging to visually correct
> the misalignment without considering the real cause become taught as
> the de facto method in the workflow. (easier than teaching about
> ellipsoids and datum math)

Added in GRASS-wiki [1]:

"GRASS' logical database structure (one projection definition per
LOCATION) is designed to avoid problems such as the ones introduced with
the "on-the-fly" reprojection ability (typically problems caused by
mixed datums) which is present in most GISes."


[1] http://grass.osgeo.org/wiki/Location_and_Mapsets

More information about the grass-user mailing list