[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: IDL Procedure to read/write USGS DEMs
Reading DEMs are pretty simple. Below is an sample of a routine I used to
read the GTOPO30 Elevation data from the CD. Swapping is required if you
are on a PC.
; Retrieve an area around Colorado
topo = INTarr(4800,6000)
OpenR, 1, 'e:\w140n90\w140n90.dem', /swap_endian ; Swapping required on PCs
ReadU, 1, topo
; Rotating not really required, IDL displays from bottom to top. Just my
topo = ROTATE(TEMPORARY(topo),7)
toposmall = topo(4150:4249, 0:99) ; Retrieve Colorado
SHADE_Surf, toposmall, shades = BYTscl(toposmall), ax=83, az=0
John Brock wrote:
> I am working on integrating topographic data at various spatial
> resolutions within a single
> USGS 7.5 minute DEM. This requires changing the data structure for a
> DEM to
> handle sections of variable resolution.
> Does anyone know of an existing IDL procedure that reads or writes USGS
> (DEM = digital elevation model). If so, I would like to use it as a
> starting point.
> John Brock