[Proj] WGS84 --> Albers coordinate transformation question

Jim Mace jmace at benchmarkrs.com
Tue Apr 10 17:23:58 EDT 2007


Thanks for all of your help.  After looking at the method signatures I
realized that I was switching the latitude and longitude around.  Stupid
rookie mistake.  Everything seems to be converting fine now.  Thanks again.
You guys are great.

Jim Mace
Application Programmer

Benchmark Research & Safety Inc.
201 W. Sprague Ave
Suite 222
Spokane, Washington 99201


-----Original Message-----
From: proj-bounces at lists.maptools.org
[mailto:proj-bounces at lists.maptools.org] On Behalf Of Ed McNierney
Sent: Tuesday, April 10, 2007 2:20 PM
To: PROJ.4 and general Projections Discussions jmace at benchmarkrs.com,
Subject: Re: [Proj] WGS84 --> Albers coordinate transformation question

Jim -

Thanks; it helps to include all that info in your problem description.  I
assumed you were using the command-line tools and making the common error
confusing the latitude (the Y coordinate) with the X coordinate (input
should be X, Y or longitude, latitude).

I think Eric's suggestion is very likely to be relevant.  Since this is a
problem in some code you've written, could you post the code snippet that's
doing the conversion?

     - Ed

-- 
Ed McNierney
President and Chief Mapmaker
Maps a la carte, Inc. / TopoZone.com
73 Princeton Street, Suite 305
North Chelmsford, MA  01863
Phone: (978) 251-4242
Fax: (978) 251-1396
ed at topozone.com

> From: Jim Mace <jmace at benchmarkrs.com>
> Organization: Benchmark Research & Safety Inc.
> Reply-To: <jmace at benchmarkrs.com>, "PROJ.4 and general Projections
> Discussions" <proj at lists.maptools.org>
> Date: Tue, 10 Apr 2007 14:00:32 -0700
> To: "'PROJ.4 and general Projections Discussions'"
<proj at lists.maptools.org>
> Subject: RE: [Proj] WGS84 --> Albers coordinate transformation question
> 
> My latitude is 45, longitude -117.
> 
> I am also using a C# wrapper for GDAL/OSR that uses the proj.4 library to
> convert coordinates.  It is only thing I could get to work in an ASP.NET
> application.
> 
> Jim Mace
> Application Programmer
> 
> Benchmark Research & Safety Inc.
> 201 W. Sprague Ave
> Suite 222
> Spokane, Washington 99201
> 
> 
> -----Original Message-----
> From: proj-bounces at lists.maptools.org
> [mailto:proj-bounces at lists.maptools.org] On Behalf Of Ed McNierney
> Sent: Tuesday, April 10, 2007 12:48 PM
> To: PROJ.4 and general Projections Discussions jmace at benchmarkrs.com,
> Subject: Re: [Proj] WGS84 --> Albers coordinate transformation question
> 
> Jim -
> 
> I get:
> 
> cs2cs +proj=latlong +datum=WGS84 +no_defs +to +proj=aea +lat_1=29.5
> +lat_2=45.5 +lat_0=23 +lon_0=-96 +x_0=0.0 +y_0=0.0 +ellps=GRS80 +units=m
> +datum=NAD83 +no_defs
> -117 45
> -1640181.94     2627681.67 0.00
> 
> 
> Are you entering -117 45 as your input, or 45 -117?
> 
>     - Ed
> 
> -- 
> Ed McNierney
> President and Chief Mapmaker
> Maps a la carte, Inc. / TopoZone.com
> 73 Princeton Street, Suite 305
> North Chelmsford, MA  01863
> Phone: (978) 251-4242
> Fax: (978) 251-1396
> ed at topozone.com
> 
>> From: Jim Mace <jmace at benchmarkrs.com>
>> Organization: Benchmark Research & Safety Inc.
>> Reply-To: <jmace at benchmarkrs.com>, "PROJ.4 and general Projections
>> Discussions" <proj at lists.maptools.org>
>> Date: Tue, 10 Apr 2007 12:10:28 -0700
>> To: <proj at lists.maptools.org>
>> Subject: [Proj] WGS84 --> Albers coordinate transformation question
>> 
>> I'm trying to convert decimal degrees, in WGS84, to Albers.  My source
> proj
>> string is (+proj=latlong +datum=WGS84 +no_defs), and my destination proj
>> string is (+proj=aea +lat_1=29.5 +lat_2=45.5 +lat_0=23 +lon_0=-96
+x_0=0.0
>> +y_0=0.0 +ellps=GRS80 units=m +datum=NAD83 +no_defs).  When I use the
>> latitude and longitude 45 and-117, respectively, I get the following
>> 0.785398163397449/-2.04203522483337.  Any ideas?
>> 
>> Jim Mace
>> Application Programmer
>> 
>> Benchmark Research & Safety Inc.
>> 201 W. Sprague Ave
>> Suite 222
>> Spokane, Washington 99201
>> 
>> 
>> 
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