[OSRS-PROJ] Bug in CEA projection?

Gerald Evenden gerald.evenden at verizon.net
Wed Jan 28 08:51:44 PST 2004


I think the problem is what source?  The last libproj4 release was
April, '03 which would have caught the version I used in the test
of my previous email.

Unfortunately, the remotesensing.org site does not use libproj4.

I expect to make a new release in the near future once the documentation
and final cleanup of Oblique Mercator (Hotine) are completed.

On Jan 28, 2004, at 11:17 AM, David Orme wrote:

> That's odd - I've just recently compiled proj4 from source but I still 
> get the wrong answer.
>
>> doibook:~ dorme$ proj +proj=cea +ellps=WGS84 +lat_ts=30 -I -f 
>> '%.6f'<<EOF
>> > 0 7284713.234
>> > EOF
>> 0.000000        82.485563
>> doibook:~ dorme$ proj
>> Rel. 4.4.7, 31 March 2003
>> usage: proj [ -beEfiIlormsStTvVwW [args] ] [ +opts[=arg] ] [ files ]
>> doibook:~ dorme$
>
> The linker details from the dynamic library are:
>
>> doibook:~ dorme$ otool -L /usr/local/lib/libproj.dylib
>> /usr/local/lib/libproj.dylib:
>>         /usr/local/lib/libproj.0.dylib (compatibility version 5.0.0, 
>> current version 5.1.0)
>>         /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, 
>> current version 71.0.0)
>
> Am I using an outdated version?
>
> Thanks,
> David
>
> On 28 Jan 2004, at 15:18, Gerald Evenden wrote:
>
>> Local lproj (libproj4) script:
>>
>> ../lproj +proj=cea +ellps=WGS84 +lat_ts=30 -I -f '%.6f'<<EOF
>> 0 7284713.234
>> EOF
>>
>> Produces the following results:
>>
>> 0.000000	82.855347
>>
>> Older versions of proj seem to have a problem.  Last change
>> to cea (libproj4) was Mar., '03
>>
>> On Jan 28, 2004, at 6:00 AM, Orme, David wrote:
>>
>>> Hi,
>>>
>>> This was cross-posted from the Grass list a while back - have I got
>>> something wrong or is this a bug?
>>>
>>> I'm using Proj 4.4.7 on my Mac 10.3.2 and ArcGIS 8 on a Windows XP
>>> machine - the two programs give different answers for coordinate
>>> transformations into  a Behrmann projection (Cylindrical Equal Area
>>> with latitude of true scale at 30 N/S). I've checked using Geotrans
>>> 2.2.4 on the Windows machine and that agrees with ArcGIS.
>>>
>>> My test point is in Behrmann coordinates, units in meters: 0E
>>> 7284713.234N
>>>
>>> cs2cs gives:
>>>
>>> > doibook:~/Library/Preferences dorme$ cs2cs -f "%0.6f" +proj=cea
>>> > +lat_ts=30 +datum=WGS84 +to +proj=latlong +datum=WGS84
>>> > 0 7284713.234
>>> > 0.000000        82.485563 0.000000
>>>
>>> Both ArcGIS and Geotrans give the following geodesic coordinates: 0 E
>>> 82.855347 N
>>>
>>> Any suggestions?
>>>
>>> Many thanks,
>>> David Orme
>>>
>>>
>>>
>> _____________________________________
>> Jerry and the low riders: Daisy Mae and Joshua
>
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_____________________________________
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