[Proj] How can I convert between cartesian space and WGS84?

[David Grundberg]

Ah, thanks!

On 10/19/2017 11:46 AM, Jose Gonçalves wrote:
> Hi
> You must have longitude first, or use option -r in cs2cs, to reverse 
> the order.
> Regards
>
> José Gonçalves
>
>
>
> 2017-10-19 9:26 GMT+01:00 David Grundberg <david.grundberg at oryx.se 
> <mailto:david.grundberg at oryx.se>>:
>
>     Hello,
>
>     I'd like to have a cartesian space, ideally in meters,
>     axis-aligned with
>     north/east/up, centered on a WGS84 position, so that I can transform
>     between this cartesian space and WGS84 coordinates. I attempted to
>     make
>     a Mercator projection but quickly ran into problems. Just to
>     illustrate,
>     I tested with geocentric projection and known coordinates.
>
>     I tested it with coordinates for a track and it should be 100 meters
>     between the points.
>
>     <https://kartor.eniro.se/?c=63.821347,20.321247&z=18&l=aerial&d={%22l%22:[[63.821477,20.321209,63.820758,20.322454,null,0]]}
>     <https://kartor.eniro.se/?c=63.821347,20.321247&z=18&l=aerial&d=%7B%22l%22:[[63.821477,20.321209,63.820758,20.322454,null,0]]%7D>>
>     or https://tinyurl.com/ybcxe3sb
>
>     $ printf "63.821477N 20.321209E\n63.820758N 20.322454E" | cs2cs -v
>     +proj=latlong +ellps=WGS84 +datum=WGS84 +no_defs +to +proj=geocent
>     +datum=WGS84 +to_meters
>     # ---- From Coordinate System ----
>     #Lat/long (Geodetic alias)
>     #
>     # +proj=latlong +ellps=WGS84 +datum=WGS84 +no_defs +towgs84=0,0,0
>     #--- following specified but NOT used
>     # +ellps=WGS84
>     # ---- To Coordinate System ----
>     #Geocentric
>     #
>     # +proj=geocent +datum=WGS84 +ellps=WGS84 +towgs84=0,0,0
>     #--- following specified but NOT used
>     # +to_meters
>     2639773.20    5369807.65 2201077.86
>     2639819.46    5369731.56 2201207.11
>     $ octave
>     octave:1> norm([2639773.20 5369807.65 2201077.86] - [2639819.46
>     5369731.56 2201207.11])
>     ans =  156.96 # Should be about 100.7 meters!
>     octave:2>
>     $
>
>     Any advice appreciated!
>     David
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-- 

David Grundberg
Developer, System Development

Phone: +46 90 348 49 28
E-mail: david.grundberg at oryx.se <mailto:david.grundberg at oryx.se>

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