[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
runtime.
>>> On 4/10/2007 at 12:10 PM, "Jim Mace" <jmace at benchmarkrs.com>
wrote:
> 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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