| Re: map MODIS HDF data to Mercator conformal projection [message #43949] |
Tue, 10 May 2005 07:34 |
wita
Messages: 43
Registered: January 2005
|
Member |
|
|
I do not really see why you would like to use IDL for this job when
MRT can do it for you. Also the MODIS HDF files are in a Sinusoidal
projection. This projection is supported by IDL's MAP_SET command
but i never used it so I can't help you with its parameters.
My advice is simple:
-use MRT to process the MODIS HDF files and specify the output corners
to project them onto a fixed grid.
-Write the result to disk as a generic binary file
-Use IDL READU function to read the binary data into an IDL array
-Use MAP_SET to set the right projection onto your data.
and you're done.
best regard,
Allard
|
|
|
|
| Re: map MODIS HDF data to Mercator conformal projection [message #43962 is a reply to message #43949] |
Mon, 09 May 2005 10:04  |
K. Bowman
Messages: 330
Registered: May 2000
|
Senior Member |
|
|
In article <1115656061.013044.326330@f14g2000cwb.googlegroups.com>,
zhangyw3982@sina.com wrote:
> I am a primary learner of IDL. Now I want to use the IDL to reproject
> the HDF data to Mercator conformal projection. I can use the IDL read
> it and TVSCL it , but I can't map it.I try to use the map_set and
> map_image. But I can't do it. I have the question? If the IDL can do
> what I hope? If it can, can you give me some help or some good ideas? I
> use the Windows system, I have take the MRT(modis reprojection tool)and
> MRTSwath. And I also try the MS2GT, all of the tools can give me most
> help. But I only want to use the IDL to it , can I ? Thanks a lot
It is very difficult to tell from the documentation, but MAP_IMAGE is designed
to plot data that is on a regular longitude-latitude grid. If you are trying to
plot swath (scan) data, you will need to use a different approach.
The simplest is to call MAP_SET and then use PLOTS to plot each satellite field
of view (fov). You need to know the longitude and latitude of every fov. Set
the display color for each fov with the COLOR keyword of PLOTS. If you need a
larger plotting marker than PSYM = 3 provides, see the USERSYM procedure.
Ken Bowman
|
|
|
|
comp.lang.idl-pvwave archive
Members
Search
Help
Login
Home
