Thanks Jeff, that's actually what I wanted to know.
Unfortunately I guess, there is a small difference between Transverse
Mercator and Universal Transverse Mercator Projections
Do I have the possibility to define somewere the UTM zone and the Datum
of my Projection.
I tried it like Jeff suggested,
map1 = Basemap(projection='tmerc',
resolution='i',llcrnrlon=-128.3841365,llcrnrlat=68.3952899,urcrnrlon=-121.5846218,urcrnrlat=70.7793990,
lon_0=-124.98437915,lat_0=69.587344449999989)
lons,lats = map1(X_utm,Y_utm,inverse='True')
but the lons and lats
look like this:
In [53]: lons
Out[53]:
array([[-124.98437915, -124.98437915, -124.98437915, ..., -124.98437915,
-124.98437915, -124.98437915],
[-124.98437915, -124.98437915, -124.98437915, ..., -124.98437915,
-124.98437915, -124.98437915],
[-124.98437915, -124.98437915, -124.98437915, ..., -124.98437915,
-124.98437915, -124.98437915],
...,
[-124.98437915, -124.98437915, -124.98437915, ..., -124.98437915,
-124.98437915, -124.98437915],
[-124.98437915, -124.98437915, -124.98437915, ..., -124.98437915,
-124.98437915, -124.98437915],
[-124.98437915, -124.98437915, -124.98437915, ..., -124.98437915,
-124.98437915, -124.98437915]])
In [54]: lats
Out[54]:
array([[ 90., 90., 90., ..., 90., 90., 90.],
[ 90., 90., 90., ..., 90., 90., 90.],
[ 90., 90., 90., ..., 90., 90., 90.],
...,
[ 90., 90., 90., ..., 90., 90., 90.],
[ 90., 90., 90., ..., 90., 90., 90.],
[ 90., 90., 90., ..., 90., 90., 90.]])
Has anyone an idea?
···
--
Anja Roesel
Center for Marine and Atmospheric Research
Institute of Oceanography, University of Hamburg
Bundesstrasse 53
D-20146 Hamburg
Germany
Tel. +49 40 42838 5430 Fax: +49 40 42838 7471
Anja: You need to pass the latitude and longitude values (in degrees)
to the Basemap instance when converting to projection coordinates. So,
to convert from UTM coordinates to polar stereographic coordinates you
will need to do something like this:
map1 = Basemap(<parameters for transverse mercator projection>)
lons, lats = map1(x, y, inverse=True) # x and y are projection
coordinates on original UTM grid.
# lons and lats are now latitudes and longitudes of UTM grid (in degrees)
map2 =
Basemap(resolution='i',projection='npstere',lon_0=-45,boundinglat=70)
x, y = map2(lons, lats)
# x,y are now polar stereo coordinates of UTM grid.
Or, if you already have the latitudes and logintudes of the original UTM
grid you can skip the first two lines and just pass those to the
stereographic Basemap instance.
-Jeff