[GRASS-user] reprojection issue, using grass6.2
Duffy, Garret
garret.duffy at nuigalway.ie
Wed Oct 12 07:29:04 EDT 2011
Hi,
I have three locations defined, one in Geographic 'projection', one UTM
and the other described below. When I try to reproject data, e.g. a
vector rectangle from either Geographic or UTM to the Oblique Mercator
projection defined below, the rectangle isn't rotated as I expect. The
origin of the projected coordinates looks to be in the correct location
but there is no rotation applied (geographic north is supposed to ~45
deg from the y axis). BTW, is it even possible to display a geodetic
grid for a non-rectified projection?
output from g.proj -p:
-PROJ_INFO-------------------------------------------------
name : Oblique Mercator
proj : omerc
a : 6378137
es : 0.006694379990141316
lat_0 : 53.25
lonc : -5.7
alpha : -88
k : 1
x_0 : 0
y_0 : 0
towgs84 : 0,0,0,0,0,0,0
no_defs : defined
-PROJ_UNITS------------------------------------------------
unit : meter
units : meters
meters : 1
The command I used to specify the oblique projection is:
proj +proj=omerc +ellps=WGS84 +k_0=1.0 +lat_0=53.25 +no_uoff +rot_conv
+alpha=-88 +lonc=-5.7
I must emphasize that I have checked the proj.4 parameters using the
command-line proj.4 and the *parameters are correct*. I applied these
parameters in GlobalMapper to get the final map to the state that I
would like eventually in GRASS.
Any advice would be *greatly* appreciated, I have spent a lot of time on
this.
Regards,
Garret
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