| Re: Georeferencing Errors [message #41640 is a reply to message #41513] |
Wed, 03 November 2004 21:21   |
Kelly Dean
Messages: 92
Registered: March 1997
|
Member |
|
|
You are on the right track, but try this instead...
TVscl, MAP_PATCH( z, lon, lat, missing=-9999, XSTART=x0, YSTART=y0 ), x0, y0
This will allow your image to be placed in the same location as your map. So there is no need to
add XMargine=0 and YMargine=0 parameters in the MAP_SET declaration.
Kelly Dean
Colorado State University
Fort Collins, Colorado
Will McCarty wrote:
> OK, I've posted on this before, and this time I'm using a bit of a
> more common dataset (GTOPO30 terrain elevation), but getting similar
> geolocation errors. Thus I'm interested in seeing what (if anything)
> you guys can come up with. I use the following code:
>
> --test_lat_lon.pro
> ulx = -99.99583333333334
> uly = 39.99583333333333
> dx = 0.00833333333333
> dy = 0.00833333333333
>
> lat = fltarr(4800,6000)
> lon = lat
> for i = 0, 4799 do begin
> for j = 0, 5999 do begin
> lat[i,j] = uly - dy*j
> lon[i,j] = ulx + dx*i
> endfor
> endfor
>
> openr,1,'W100N40.DEM'
> z = intarr(4800,6000)
> readu,1,z
> close,1
>
> z = swap_endian(z)
> map_set,mean(lat),mean(lon),/cylindrical,limit=[min(lat),min (lon),max(lat),max(lon)],/noborder
>
> rmz = map_patch(z,lon,lat,missing=-9999)
> tvscl,rmz
> map_continents
> end
> ---end
>
> to put the topographic info to a projection. The result is at
> http://vortex.nsstc.uah.edu/~mccarty/georef-err.png. Clearly there
> are some georeferencing errors. I've tried both idl 5.6 (my normal
> version) as well as 6.0. Similarly, I've tried multiple projections.
> I've got some theories, but i'm looking to the experts on this one.
>
> Thanks for any help you folks can provide.
>
> Will
|
|
|
|
comp.lang.idl-pvwave archive
Members
Search
Help
Login
Home
