[Proj] Dubai Palm Island Projection

[Oscar van Vlijmen]

> From: "Andreas Rappensperger" <andreas.rappensperger at googlemail.com>
> Date: Tue, 27 Feb 2007 15:12:05 +0100
> Subject: [Proj] Dubai Palm Island Projection

> I have the following problem. I would like to rotate the Dubai Palm Island so
> that the palm stand vertical. The rotation point should be the middle point
> of the Palm. In Dubai usually the DLTM projection is used.
...
> Now I tried to define my own coordinate system with the following parameter:
> # DP Dubai Palm (DLTM rotated by -49 degree)
> proj=omerc lat_0=25.095311 lonc=55.137296 alpha=-49.0000000
> k=1.000000 x_0=500000.000 y_0=0.000 ellps=WGS84 units=m
> But it does not work. I have created a test. I have taken two points
> Bottom of the Palm: 55.154200° 25.102206°
> Top of the Palm: 55.122691° 25.126338°
...

Try the no_rot option, then you'll stay in u,v coordinates, which are with
respect to the central line.
With your data I got an angle of -0.93 deg (atan2 of top minus bottom u,v
coordinates). That's nice because the geodesic azimuth angle between
top->bottom is not -49 deg but actually -49.923 deg.