[Proj] International 1924 Authalic Sphere needed for EASE-Grid Snow
data
Markus Neteler
neteler at osgeo.org
Thu Nov 6 05:51:24 EST 2008
Fellow list members,
I am trying to reproject Global EASE-Grid 8-day Blended SSM/I and
MODIS Snow Cover
which are projected in EASE-Grid North (AFAIK it is EPSG 3408):
http://nsidc.org/data/ease/ease_grid.html
Using the EPSG tool of GDAL, I obtain the following
epsg_tr.py 3408
PROJCS["NSIDC EASE-Grid North",
GEOGCS["Unspecified datum based upon the International 1924
Authalic Sphere",
DATUM["Not_specified_based_on_International_1924_Authalic_Sphere",
SPHEROID["International 1924 Authalic Sphere",6371228,0,
AUTHORITY["EPSG","7057"]],
AUTHORITY["EPSG","6053"]],
PRIMEM["Greenwich",0,
AUTHORITY["EPSG","8901"]],
UNIT["degree",0.01745329251994328,
AUTHORITY["EPSG","9122"]],
AUTHORITY["EPSG","4053"]],
UNIT["metre",1,
AUTHORITY["EPSG","9001"]],
PROJECTION["Lambert_Azimuthal_Equal_Area"],
PARAMETER["latitude_of_center",90],
PARAMETER["longitude_of_center",0],
PARAMETER["false_easting",0],
PARAMETER["false_northing",0],
AUTHORITY["EPSG","3408"],
AXIS["X",UNKNOWN],
AXIS["Y",UNKNOWN]]
However, the International 1924 Authalic Sphere seems to be missing
from PROJ4.
Could this be officially added? Is it as simple as this code change (maybe
there is a better name to find)?
svn diff src/
Index: src/pj_ellps.c
===================================================================
--- src/pj_ellps.c (revision 1490)
+++ src/pj_ellps.c (working copy)
@@ -40,6 +40,7 @@
"kaula", "a=6378163.", "rf=298.24", "Kaula 1961",
"lerch", "a=6378139.", "rf=298.257", "Lerch 1979",
"mprts", "a=6397300.", "rf=191.", "Maupertius 1738",
+"intl1924", "a=6371228.0", "b=6371228.0", "International 1924
Authalic Sphere",
"new_intl", "a=6378157.5", "b=6356772.2", "New International 1967",
"plessis", "a=6376523.", "b=6355863.", "Plessis 1817 (France)",
"SEasia", "a=6378155.0", "b=6356773.3205", "Southeast Asia",
Best regards,
Markus Neteler
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