<div dir="ltr"><div><div><div>Hi<br></div>You must have longitude first, or use option -r in cs2cs, to reverse the order.<br></div>Regards<br><br></div>José Gonçalves<br><br><div><div><br></div></div></div><div class="gmail_extra"><br><div class="gmail_quote">2017-10-19 9:26 GMT+01:00 David Grundberg <span dir="ltr"><<a href="mailto:david.grundberg@oryx.se" target="_blank">david.grundberg@oryx.se</a>></span>:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hello,<br>
<br>
I'd like to have a cartesian space, ideally in meters, axis-aligned with<br>
north/east/up, centered on a WGS84 position, so that I can transform<br>
between this cartesian space and WGS84 coordinates. I attempted to make<br>
a Mercator projection but quickly ran into problems. Just to illustrate,<br>
I tested with geocentric projection and known coordinates.<br>
<br>
I tested it with coordinates for a track and it should be 100 meters<br>
between the points.<br>
<br>
<<a href="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]]}" rel="noreferrer" target="_blank">https://kartor.eniro.se/?c=<wbr>63.821347,20.321247&z=18&l=<wbr>aerial&d={%22l%22:[[63.821477,<wbr>20.321209,63.820758,20.322454,<wbr>null,0]]}</a>><br>
or <a href="https://tinyurl.com/ybcxe3sb" rel="noreferrer" target="_blank">https://tinyurl.com/ybcxe3sb</a><br>
<br>
$ printf "63.821477N 20.321209E\n63.820758N 20.322454E" | cs2cs -v<br>
+proj=latlong +ellps=WGS84 +datum=WGS84 +no_defs +to +proj=geocent<br>
+datum=WGS84 +to_meters<br>
# ---- From Coordinate System ----<br>
#Lat/long (Geodetic alias)<br>
#<br>
# +proj=latlong +ellps=WGS84 +datum=WGS84 +no_defs +towgs84=0,0,0<br>
#--- following specified but NOT used<br>
# +ellps=WGS84<br>
# ---- To Coordinate System ----<br>
#Geocentric<br>
#<br>
# +proj=geocent +datum=WGS84 +ellps=WGS84 +towgs84=0,0,0<br>
#--- following specified but NOT used<br>
# +to_meters<br>
2639773.20 5369807.65 2201077.86<br>
2639819.46 5369731.56 2201207.11<br>
$ octave<br>
octave:1> norm([2639773.20 5369807.65 2201077.86] - [2639819.46<br>
5369731.56 2201207.11])<br>
ans = 156.96 # Should be about 100.7 meters!<br>
octave:2><br>
$<br>
<br>
Any advice appreciated!<br>
David<br>
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