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Re: [ferret_users] Orthographic projection - variable from 1-degree model



Jan,

I suggest to use ncdump to investigate the data set first.

ncdump -h test.nc tells me, your dataset contains only 320 longitude values between 1- 320. The axis is not periodic (modulo).  There are no units to tell ferret that axis are in degrees. Latitudes are running from 1 - 384. So your planet is not really the earth, at least the coordinates are different. Ferret tries its best to put data onto earth-like coordinates. This explains for me the gap between 320 to 360.

I guess the coordinates are generally missing in your file. Instead you have only an grid point index yet. I suggest to put the data onto new correct axis, but I cannot see how to put 384 latitudes onto a 1deg grid, which requires only about 180 values. Is the latitude axis more dense near the equator. Please try to get more complete information about the model grid, before you continue with ferret.  Any graphics tool, not only ferret, needs this information to deliver correct plots.

Best,
Martin


On 06/19/2018 03:20 PM, niciej wrote:
Dear Ferreters,
I have a data set(test.nc) with SSH variable from 1-degree model.
Basic Ferret plot of SSH is shown on PIC1
I'm trying to plot it using orthographic projection:

use test.nc

SET REGION/X=0:360/Y=-90:90/L=1

GO mp_orthographic 10 45

SET GRID ssh

GO mp_aspect

LET masked_ssh = ssh * mp_mask

FILL/NOAX/NOLAB masked_ssh, x_page, y_page

LABEL/NOUSER `($PPL$XLEN)*0.5`,-0.4,0,0,0.2 View From Space

GO mp_fland

GO mp_land

GO mp_graticule

My results are shown on PIC2 - the projection is incorrect, moreover there is a gap between 320 - 360 deg.
How can I get a correct projection?
Thanks a lot,
Jan Niciejewski
Institute of Oceanology PAS


--
Dr. Martin Schmidt
Leibniz-Institute for Baltic Sea Research
Seestrasse 15
D18119 Rostock
Germany




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