Latitude/longitude, contours, map_set, iMap? [message #43913] |
Tue, 03 May 2005 19:13 |
jamiesmyth_uni@yahoo.
Messages: 6 Registered: July 2004
|
Junior Member |
|
|
I should caveat this by saying I need to plot data on maps about twice
a year and every time it is more difficult than I expect it to be. I
have some atmospheric model data for temperature (originally grib data)
on a latitude/longitude grid and I'm having quite a difficult time
plotting it with the iMap and/or the map_set routines. The first
problem I have is that the longitude data goes from 0-360 degrees. So
I have:
LAT FLOAT Array[73]
LON FLOAT Array[96]
PRESSURE FLOAT Array[22]
TEMPERATURE FLOAT Array[73, 96, 22]
where the latitdes go from -90 to +90 in 2.5 degree steps and the
longitudes go from 0 to +360 in 3.75 degree steps. I've read some past
messages on how to re-work the longitude to -180 to 180 degrees and
have:
lon_new = lon - (long(lon)/180L)*360.0
Do I have to also alter the temperature array to reflect this change or
can I simply plot the data with:
imap, transpose(data.pv[*,*,0]), data.lon, data.lat
or
map_set, /continents, /mercator, /isotropic
contour, transpose(data.pv[*,*,0]), data.xlon, data.xlat, /overplot,
nlevels=12
The first command brings up a dialog box for the 'gridding wizzard' but
when I click ok, nothing happens. The second looks 'more-or-less' ok
but there seems to be a gap at 0 degrees. The gap is rather apparent
when I fill the contours... Do I need to re-grid or triangulate the
data? Is there a quick way to do any of this?
I'd much prefer to use imap here as it makes figures that look much
better in powerpoint.
Any ideas and help would be much appreciated... I'm supposed to be
putting these figures (along with some polar stereographic projections)
into a talk for thursday! Reaching for brown-paper bag... taking
deep-breaths...
Thanks
Jamie
|
|
|