[MetaCRS] failed epsg wkt (geotools)

[Mikael Rittri]

Thanks for your efforts. 
But may I call attention to eleven coord. ref. systems that are wrong 
on SpatialReference.org. (I am not sure what causes the errors.) 

First: 

* EPSG:3388, Pulkovo 1942 / Caspian Sea Mercator

According to EPSG, the projection method is "Mercator (2SP)", coord op method 9805, 
with a standard parallel at 42°N.
But on SpatialReference.org, the projection method in OGC WKT is given as "Mercator_1SP", 
and the standard parallel is absent from the parameters.

The other ten that are wrong are: 

* EPSG:2056,  "CH1903+ / LV95"
* EPSG:2057,  "Rassadiran / Nakhl e Taqi"
* EPSG:21780, "Bern 1898 (Bern) / LV03C"
* EPSG:21781, "CH1903 / LV03"
* EPSG:23700, "HD72 / EOV"
* EPSG:29700, "Tananarive (Paris) / Laborde Grid",
* EPSG:29702, "Tananarive (Paris) / Laborde Grid approximation"
* EPSG:29871, "Timbalai 1948 / RSO Borneo (ch)"
* EPSG:29872, "Timbalai 1948 / RSO Borneo (ft)"
* EPSG:29873, "Timbalai 1948 / RSO Borneo (m)"

According to EPSG, all these use the projection method "Oblique Mercator", coord op method 9815.
But on SpatialReference.org, these ten CRSs are given the projection method "Hotine_Oblique_Mercator",
which is a different method (coord op method 9812).   

It is true that each instance of "Oblique Mercator" can be reformulated as an instance of 
"Hotine Oblique Mercator", but this requires that you adjust the False Easting and False Northing,
which has not been done.  EPSG Guidance Note 7.2 gives the example of "Timbalai 1948 / R.S.O. Borneo (m)",
which has 
    Easting at projection centre  (EC) = 590476.87 metres
    Northing at projection centre (NC) = 442857.65 metres

This can be reformulated as an instance of "Hotine Oblique Mercator", but only if you adjust
these parameters to 
    False easting (FE) = 0.0 metres
    False northing (FN) = 0.0 metres

Note also that some CRSs in the ESPG database do use "Hotine Oblique Mercator", so 
it is no solution to just replace "Hotine_Oblique_Mercator" by "Oblique_Mercator" 
everywhere.  The two coord op methods must be distinguished. 

Best regards,

--
Mikael Rittri
Carmenta AB
Box 11354
SE-404 28 Göteborg
Visitors: Sankt Eriksgatan 5
SWEDEN
Tel: +46-31-775 57 37
Mob: +46-703-60 34 07 
mikael.rittri at carmenta.com
www.carmenta.com 

-----Original Message-----
From: metacrs-bounces at lists.osgeo.org [mailto:metacrs-bounces at lists.osgeo.org] On Behalf Of Christopher Schmidt
Sent: den 16 december 2008 00:18
To: metacrs at lists.osgeo.org
Subject: [MetaCRS] failed epsg wkt (geotools)

SpatialReference.org now has a full EPSG database, pulled from the latest EPSG data files, with WKT produced by either GDAL or GeoTools for every code except for the following (along with their error messages from GeoTools):

5818 failed:  Unknow axis direction: "Along receiver lines".

63266406 failed:  Unsupported unit: 9116
63266407 failed:  Unsupported unit: 9117
63266408 failed:  Unsupported unit: 9115
63266409 failed:  Unsupported unit: 9118 63266410 failed:  Unsupported unit: 9119
63266412 failed:  Unsupported unit: 9120
63266414 failed:  Unsupported unit: 9116
63266415 failed:  Unsupported unit: 9117
63266416 failed:  Unsupported unit: 9115
63266417 failed:  Unsupported unit: 9118
63266418 failed:  Unsupported unit: 9119 63266420 failed:  Unsupported unit: 9120

4882 failed:  Unknow axis direction: "Geocentre > equator/0?E".
4884 failed:  Unknow axis direction: "Geocentre > equator/0?E".
4886 failed:  Unknow axis direction: "Geocentre > equator/0?E".
4888 failed:  Unknow axis direction: "Geocentre > equator/0?E".
4890 failed:  Unknow axis direction: "Geocentre > equator/0?E".
4892 failed:  Unknow axis direction: "Geocentre > equator/0?E".

This is mostly just a 'for the record': At some point, I may look into this more to see if these codes should actually exist in some way. 5818 is almost definitely "no", since the scope says "Example only", but the
4882 -> 4892 set seems like a clear pattern that bears investigation. 

If anyone has suggestions as to ways to obtain sane WKT for these remaining codes, I'd love to hear suggestions.

Regards,
--
Christopher Schmidt
MetaCarta
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