| matchup of Map_set & contour [message #36276] |
Wed, 03 September 2003 06:37  |
shson
Messages: 8
Registered: August 2003
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Junior Member |
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Hello~
I want to overlap contour lines on a map.
However, I think it doesn't match exactly (I checked the gridlines)..
especially, as it goes to the edge..
Could someone know how to fix it?
Here is an example...
;-------------------------------
lon = FINDGEN(91)
lat = FINDGEN(115)
x = 17.0 + lon*(1/6.0)
y = 23.0 + lat*(1/6.0)
seed=1L
temp = sin(x)^2 * cos(x)
z = DIST(91,115)
LOADCT, 39
WINDOW,1,TITLE='WORLD MAP',xsize=800,ysize=900
CONTOUR, z, x, y, /Follow, position=[0.1,0.1,0.9,0.9] $
, NLevels=20, XStyle=1, YStyle=1, /NoErase, /FILL ;$
MAP_SET, /CYLINDRICAL, LIMIT=[23.0,17.0,42.0,32.0], /CONTINENTS $
, /HIRES, Mlinethick=1., position=[0.1,0.1,0.9,0.9] $
, /Noerase;, /ISOTROPIC
MAP_CONTINENTS, /HIRES,color=255, /FILL_CONTINENTS, /CYLINDRICAL ; /mercator
MAP_CONTINENTS, /COAST, color=0, /HIRES, /CYLINDRICAL ; /mercator
MAP_GRID, charsize=1.25, color=100 ,latdel=2, londel=2 $
, /BOX_axes, GLineStyle=2
;-------------------------------
Thank you.
Sincerely.
Son
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| Re: matchup of Map_set & contour [message #36360 is a reply to message #36276] |
Thu, 04 September 2003 08:23  |
Chris Lee
Messages: 101
Registered: August 2003
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Senior Member |
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In article <62cdb6eb.0309031011.6e9ce978@posting.google.com>, "Son"
<shson@darkstar.sr.unh.edu> wrote:
> Thanks a lot!
> Now, it works very well.
> When you have a time, please explain why 'contour' line should be after
> 'map_set' when you have a time? Son
Try setting the map projection to anything other than mercator (try
/goodes) and remove the limit. Plotting the contour before using map_set
causes a map to be drawn over the unprojected contour.
Contur (ing) after the map_set (with the /over keyword) tells IDL to use
the graphics projection that you have already set up.
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| Re: matchup of Map_set & contour [message #36362 is a reply to message #36276] |
Wed, 03 September 2003 15:01 |
David Fanning
Messages: 11724
Registered: August 2001
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Senior Member |
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Son writes:
> When you have a time, please explain why 'contour' line should be
> after 'map_set' when you have a time?
This is primarily because the "IDL way" is to
fit data to map projections, not to fit map
projections to data. In any case, it is the
MAP_SET call that sets up all the data to device
coordinate conversion factors, etc. that are needed
for overplotting data on the map. This is similar
to what happens when you issue a PLOT command.
Cheers,
David
--
David W. Fanning, Ph.D.
Fanning Software Consulting, Inc.
Phone: 970-221-0438, E-mail: david@dfanning.com
Coyote's Guide to IDL Programming: http://www.dfanning.com/
Toll-Free IDL Book Orders: 1-888-461-0155
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