[Gdal-dev] EPSG 6.5 and extended Dictionary lookups

[Frank Warmerdam]

Folks,

As part of the GDAL 1.2.0 release I updated to EPSG 6.5 coordinate systems.
That should be in the beta snapshot.

I have also (in CVS) added support for reading coordinate system dicionaries.
This mechanism basically allows coordinate system codes to be looked up in
a text file (from the GDAL data directory), where the code is corresponded
to a WKT representation of the coordinate system.

I am currently using these dictionary files to hold a bunch of "non-standard"
EPSG coordinate systems. Basically a bunch of special codes uses in the WMS
world (and harvested from a CubeWerx dictionary in a similar format) and
from all the non-EPSG ESRI coordinate systems normally found in their "epsg"
directory.

The dictionary files are just simple text files, following the following
rules:
  o Empty lines, or lines starting with "#" are ignored (comments).
  o Lines starting with "include " can name an additional file that will
    be searched.
  o data lines should be a code seperated from the WKT representation by a
    comma.

eg.

include cubewerx_extra.wkt
#
#  OGC-defined "AUTO" codes
#  http://www.digitalearth.gov/wmt/auto.html
#
42001,PROJCS["WGS 84 / Auto UTM%s",GEOGCS[...]]
42002,PROJCS["WGS 84 / Auto Tr. Mercator",...]

A new method, OGRSpatialReference::importFromDict() has been added supporting
the dictionaries.  As well the SetFromUserInput() now supports the funky format
"DICT:filename,code" as a way of requesting an arbitrary dictionary entry.
Also, the importFromEPSG() method will now search the epsg.wkt dictionary
(which includes the cubewerx and esri definitions) *if* the coordinate system
isn't found in the pcs.csv or gcs.csv files.

Other than providing a heads up, I am writing to see if there is anyone
interested in coordinate system use through GDAL that would like a crack
at testing this *before* the 1.2.0 release.  If so, please grab a nightly
snapshot and give it a spin.

Best regards,
-- 
---------------------------------------+--------------------------------------
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent