| Re: Plot and Plots [message #58454 is a reply to message #58453] |
Thu, 31 January 2008 13:53   |
Paul.Bowyer@gmail.com
Messages: 7
Registered: September 2007
|
Junior Member |
|
|
On Jan 31, 7:27 pm, David Fanning <n...@dfanning.com> wrote:
> pb24 writes:
>> I am trying to produce a graphic showing continent outlines,
>> coastlines etc, with a graticule and the footprint of a satellite
>> image. I can do all this by using MAP_SET, and then I use PLOTS to
>> plot a vector of the image coordinates. Using MAP_SET however, I can
>> only specify a STEREOGRAPHIC projection, when I want a POLAR
>> STEREOGRAPHIC projection.
>
>> To get a POLAR STEREOGRAPHIC projection I need to use MAP_PROJ_INIT
>> and then PLOT to display the graticule. However when I do this I cant
>> seem to get PLOTS to display the image footprint. I have converted my
>> image footprint coordinates from lat./long. to cartesian using
>> MAP_PROJ_FORWARD, but using PLOTS just doesnt work. Any ideas from
>> anyone would be gratefully received. Is it not possible to use PLOT
>> and PLOTS together??
>
> I suspect the problem is the way you are using PLOT to set
> up your UV data coordinate space. The code will look something
> like this:
>
> polar = Map_Proj_Init(1, CENTER_LAT=90, CENTER_LON=0)
> uvgraticule = Map_Proj_Forward(graticule, MAP_STRUCTURE=polar)
> uv_box = polar.uv_box
> Plot, uv_box[[0, 2]], uv_box[[1, 3]], Position=[0.1,0.1,0.9,0.9], $
> /Nodata, XStyle=5, YStyle=5, /NoErase
> Oplot, uvgraticule ; Or MAP_grid, MAP_STRUCT=polar, /LABEL, etc.
>
> Cheers,
>
> David
> --
> David Fanning, Ph.D.
> Fanning Software Consulting, Inc.
> Coyote's Guide to IDL Programming (www.dfanning.com)
> Sepore ma de ni thui. ("Perhaps thou speakest truth.")
Hi David,
Thanks for your reply.
I have no trouble displaying the graticule and the continents using
MAP_GRID,and MAP_CONTINENTS. The problem is that once I have these
displayed, I'd like to plot the satellite image footprint on top by
taking the four image corner coordinates and using PLOTS. I have done
this using PLOTS when used in combination with MAP_SET (and with a
stereographic projection), but I want ideally, to have a *polar
stereographic* projection (they are not the same sadly - map
projections!!). That is why I am having to use MAP_PROJ_INIT with 106
projection number a GCTP type. Hope that makes my initial post a
little clearer.
Thanks again,
Paul
|
|
|
|
comp.lang.idl-pvwave archive
Members
Search
Help
Login
Home
