Need: way to add a terrain graphic as a backdrop
under plots we make using (Fortran) NCAR graphics
For a few years I've used NCAR Graphics to plot gridded rain
using hourly Unix C-shell scripts. How might we add a terrain
background from outside NCAR Graphics (PostScript or HDF or gif or
whatever we need to convert it to) and lay it down first under a
plot so grid squares currently plotted black (no rain) will now
be left unplotted, for the terrain background to show through?
(Regretably, with on-line manuals these days for NCAR Graphics, it
becomes badly time wasting, ending up getting almost nowhere.)
As examples of what we've been doing, you may go to either of
http://yampa.earthsci.do.usbr.gov:8080/awards/Mn/index.html
then click on North Central US Composite
(the initial plot here was by Dr. Holroyd not in NCAR Graphics)
then click on 24-hr under one of the days of the week
http://www.usbr.gov/rsmg/nexrad/
then click on NEXRAD Level III Rainfall and ET Products
for Western Oregon
then click on Tualatin Project AWARDS System
(this may be the first plot we lay a terrain background under)
- programmer Ra Aman
More Details (from Steffen P Meyer)
The backgrand we intend trying first is a hill shade being
created in a GIS application. The anticipated path will use USGS
DEM data, read elevation lattice data into ESRI ArcInfo 7.2.1 or
ArcView 3.2 as a raster grid. Derivative products to create a
meaningful slope, aspect and shaded relief grids.
In ArcInfo the SAI (Slope Aspect Index) or HILLSHADE function
will be used, while in ArcView hillshade scripts will be executed.
In either case, ESRI grid will be exported. The data itself could
be exported from ESRI application or a product that could be
utilized by NCAR graphics.
Our question has to do with how 1. prepare source data, or 2.
prepare a product readily used by NCARG, or 3. utilize a transform
of soure data or transformed output product from the GIS most
efficieintly within NACR Graphics. Future use of ESRI GIS output
may involve other grids and polygons as well.
We have established a means to plot polygon data that have been
transformed for use by NCAR plot routines.
The source grid data can be exported to file in ArcView as a
Raster ASCII or Raster Binary .
The export formats conveniently available from ArcView include
Placeable Windows Meta file (WMF) Adobe Illustrator
Windows Metafile Windows Bitmap
Postscript New (EPS) Postscript (EPS)
GCM Binary CGM Character
Clear Text JPEG
As an alternative, we could convert one of these products to a
format that NCARG can read. This might involve converting a file to
HDF or some other format.
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