[gdal-dev] [PATCH v2] Support Mercator_2SP in GeoTIFF

[Antti Castrén]

Hello Trent, Even et al.



Your work and comments on GeoTIFF and Mercator 2sp hopefully addresses the
problem I ran into few years ago. I wrote a description to ESRI's forums
with extracts of header information by ArcGIS and Geomedia. The postings
are at:

http://forums.arcgis.com/threads/24850-Projection-problem-with-GeoTIFFs-and-Mercator



Since then I have seen the similar behavior in other software also. It
confuses my geodesist-engineer-brain a little to see the terms latitude of
origin, latitude of true scale, standard parallel and natural origin
latitude used more or less interchangeably...



If you need volunteer for testing the patch or to give more insight to the
problem I am more than willing. Hopefully the software vendors follow the
resulting changes in specs.



To circumvent the whole problem I have advised my colleagues to reproject
their future Mercator_2sp GeoTIFFs to the Equator. This way the scale
problem disappears since both latitude parameter values are in fact 0. In
addition they can then use predefined CRS-code EPSG::3395, because nautical
charts are nowadays by international standards published using WGS84 as
horizontal datum.



Cheers,



  Antti
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/gdal-dev/attachments/20131111/29f0557c/attachment.html>