[Proj] ERROR 6: No translation for Lambert Conformal Conic toPROJ.4 format is known.
warmerdam at pobox.com
Wed Apr 1 14:52:18 EST 2009
Eric Miller wrote:
> ArcGIS (9.1 at least) has "Lambert_Conformal_Conic" for U.S. state
> plane definitions and others. All of the definitions I looked at had
> two standard parallels.
> I'm not sure where the 1SP and 2SP stuff comes from. The Simple
> Features Spec. for OLE (1.1) appendix 4-6 only lists "Lambert conformal
> conic." So, the software in question is using the listed name. The
> practice of replacing spaces with underscores in never mentioned. The
> examples use underscores but the list of supported projections does not
> have underscores and there is no direction that underscores should be
> used or supported.
I believe the 1SP and 2SP naming comes from EPSG. Reviewing
OGC 99-049 (SFSQL 1.1) I see it does not list many example PROJECTION
keywords. I only noticed "Transverse_Mercator". The list of projection
methods lists this as "Transverse Mercator", but it is not at all
clear that this list is intended to represent the keyword values.
> Thus, I think a robust WKT interpreter must accept projection names
> with or without underscores and with or without the _1SP or _2SP
> refinements. (If needed, it must look at the parameters to
> disambiguate.) Additionally, there probably needs to be handling for
> hyphens (missing or present) and accents/non-ascii (missing, present or
> alternate spelling). Is it "Plate-Carée" or "Plate_Caree" or
> "Plate-Carree" or "Plate_Carree" or ... ? Only the first version is
> listed in appendix 4-6. Perhaps it's easiest just to maintain a table
> of synonyms?
The WKT specification is grossly incomplete leaving us with such
ambiguities. One approach is to have lots of guessing based on similar
names or lots of translation dictionaries. I have taken the practice
instead of documenting "OGR WKT" and preparing morphing functions to
convert it to/from other representations. The most noteworthy implementation
is the one for ESRI (Projection Engine) WKT.
I am now taking the approach that for any projection method not currently
supported in GDAL/OGR that I will adopt the ESRI PE formulation since it
is the form with widest industry adoption. I wish I had done this sooner
(from the beginning).
I would note that CS-Map maintains extensive translation tables to convert
between the WKT represention of various software packages.
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
More information about the Proj