| Re: Using IDL's map database [message #5860] |
Mon, 04 March 1996 00:00 |
Hermann Mannstein
Messages: 22
Registered: September 1995
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Junior Member |
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dean@phobos.cira.colostate.edu wrote:
>
> I would like to access the IDL map data base to add a map to satellite
> images from GOES-8 or GOES-9. I have an algorithm to do this ( MAP_SET, /SAT
> doesn't map correctly), but I need lat/long numbers to draw a map over my
> image.
>
> Is there a way to obtain this information from IDL's high resolution data
> set?
yes, the structure of the IDL high resolution data set is exactly the same as
it has been in the old SMA routines by Thomas Oettli, and the data within is
chains of lat/long numbers.
First read the index-file - .../maps/high/*.ndx:
with
nsegs=0L
openr, lun, ndxf, /xdr, /get_lun
readu, lun, nsegs
ndx=replicate( { fptr:0L, npts:0L,maxlat:0.,minlat:0.,$
maxlon:0.,minlon:0. },nsegs )
readu, lun, ndx
free_lun, lun
and then the *.dat (here: map_f) with
openr, lun, /get, map_f, /xdr, /stream
for i=0,n_elements(ndx)-1 do begin
point_lun, lun, mmndx(ndx(i)).fptr
xy=fltarr(2,mmndx(ndx(i)).npts)
readu, lun, xy
..........
endfor
xy are the lat/lon coordinates of one line segment.
--
Regards,
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~
Hermann Mannstein Tel.: +49 8153 28-2503
Institut fuer Physik der Atmosphaere or -2558
DLR - Oberpfaffenhofen Fax.: +49 8153 28-1841
Postfach 1116 \ mailto:H.Mannstein@dlr.de
D-82230 Wessling \ 0 http://www.op.dlr.de/~pa64
Germany ________\/|________
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