[Proj] WGS84 --> Albers coordinate transformation question

Eric Miller EMiller at dfg.ca.gov
Tue Apr 10 16:15:59 EDT 2007

If you're using the API, you have to convert lat/long coordinates to
radians before a transformation.  Similarly, results that return
lat/long return radians.  The API has some constants defined for this
purpose (DEG_TO_RAD, RAD_TO_DEG).  The function pj_is_latlong will tell
you if a projection definition is lat/long if you need to find out at

>>> On 4/10/2007 at 12:10 PM, "Jim Mace" <jmace at benchmarkrs.com>
> 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
> string is (+proj=aea +lat_1=29.5 +lat_2=45.5 +lat_0=23 +lon_0=-96
> +y_0=0.0 +ellps=GRS80 units=m +datum=NAD83 +no_defs).  When I use
> 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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