[Proj] lat/long to northing/easting and back again

[Roger Oberholtzer]

I have always used proj to convert WGS84 lat/long values to
northing/easting values in various parts of the world. In doing so, I
usually need to interpolate between points to find specific locations.
These interpolated locations have always been reported as
northing/easting values in meters. Job finished.

I now have a use where, after determining the interpolated
northing/easting, I need to convert the location back into lat/long in
degrees. This I have never done with proj.

My question is, if you had to locate a position between two lat/long
values, how would you best do this with proj? The source data in my case
is WGS84 values from a Trimble GPS. The 'interpolated' lat/longs should
also be reported in WGS84. In reality, the values will be collected
throughout Germany. But everything is requested to be provided in WGS84.

I use the C API for this. But any pointers are welcome. If I have left
out any important detail, just ask.


-- 
Roger Oberholtzer

OPQ Systems / Ramböll RST

Ramböll Sverige AB
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