HowTo Mosaic ASTER Global Digital Elevation Model (GDEM)

A second version of ASTER GDEM was released in Oct. 17 2011 by The Ministry of Economy, Trade and Industry of Japan (METI) and the National Aeronautics and Space Administration (NASA). The GDEM is in a 30m pixel resolution and 1x1 degree tiles. The data is distributed as zipped GeoTIFF files. When a larger than 1x1 deg. DEM is needed for Interferometry processing, you can use my GDEM.py script available from my script page. This python script will need a system with pylab and PIL python modules.

Simply:

Download the GDEM zipped files (see here on how to do that).

Unzip the zip files in the working directory.

The working directory should contain sub-directories containing the GeoTIFF files.

Run the script giving -h for help or the final DEM name as arguments.

The Final DEM is aimed for using as DEM in ROI-PAC interferometry processing.

If a -g is added as an argument, the produced DEM will be suitable for interferometric processing using Gamma software.

RoiView - Explore InSAR data and more

RoiView was originaly designed to replace DGX/MDX software which require bureaucracy to obtain. This software was used in order to view ROI-PAC interferometry processing results but producing an image from file was not so strait forward. In time support was added for ERDAS ER Mapper header files and for user provided parameters with or without header files.

Current RoiView version (0.75) is available for download at
See also RoiView's help files

Screenshot:

HowTo view a ROI PAC file? (or "replacement for mdx")

The Problem:
I can't get mdx/dgx in order to view my ROI PAC files.
The Solution:
a Python script called roiview (Get RoiView at ) wich is one of my other scripts.
This script uses pylab and can read, display and save images of ROI PAC quite similar to mdx/dgx.
it can handle *.unw, *.cor, *.slc, *.int and *.dem files.
just download, extract and use:
"roiview -h" for manual.
Update! Oct 13, 2010: A new version of RoiView (0.75) is now available at:

HowTo Create a SRTM DEM for ROI PAC Processing

When Processing interferograms, usually, you will also require a DEM. The NASA's SRTM project is freely available from different places in different formats and levels. The latest version for now (IV) is available from CGIAR Consortium for Spatial Information.
in order to ease the DEM production for a research, I wrote a small Python script. The script will create a DEM with 1 deg to each side of the center of scene requested. It will create a ROI PAC header as well. there is an option to create a JPG image of shaded relief of the imag. You will need Python to be installed and also PyLab and PIL modules.

simply download SRTM.py (zip,2.9kb) from my scripts page, change permission to execute, and run it...

Don't forget to credit CGIAR for the data. Citations should be made as follows: Jarvis A., H.I. Reuter, A. Nelson, E. Guevara, 2008, Hole-filled seamless SRTM data V4, International Centre for Tropical Agriculture (CIAT), available from http://srtm.csi.cgiar.org/

Orbits and other auxiliary data

I use Delft orbital data (ODR) which is available from here. don't forget to use the precise version and to download all .ODR files (make sure it is not .odr after downloading) and the arclist. also, download and install getorb software and link or move the executables to the ROI_PAC binaries directory.

I also use DORIS orbital data for Envisat which is available from here. but will require a user and password. the DORIS data is used when no ODR data is yet to be available for new Envisat images.

for Envisat I also use auxiliary data available from here.

in my lab, all the orbital data is in ~/ROI_PAC_3_0/Delft with directory tree as follows:

in ~/ROI_PAC_3_0/Delft I put the Envisat auxiliary data (INS and XCA files)

• doris/Envisat/YYYYMM contains orbital data for the year (YYYY) and month (MM)
• Envisat contains Envisat Delft orbit data (.ODR .res arclist files)
• ERS1 contains ERS1 Delft orbit data (.ODR .res arclist files)
• ERS2 contains ERS2 Delft orbit data (.ODR .res arclist files)

the files must be updated from time to time as more images are added to the list.

ROI PAC installation

UPDATE: Oct 9, 2011 (for version 3.0.1):

first download ROI-PAC and test data from open channel Foundation

I will assume the tar files are extracted at home directory (~), but it can be anywhere you wish.

don't forget to grand read/write access to relevant users.
make sure you have at least gcc and gfortran installed on your system.

go to ~/ROI_PAC_3_0_1/ROI_PAC/ directory.

follow steps described in ~/ROI_PAC_3_0_1/ROI_PAC/AAREADME_BUILD_ROIPAC up until line:
which uncompress

make sure you have a TEST DIR testing data to test the compiled program. this directory should be tared but not gzipped using:
gunzip roi_pac_test_dir.tar.gz
this will convert the roi_pac_test_dir.tar.gz to roi_pac_test_dir.tar
then create a directory test-runs in the ROI_PAC directory.
cd test_runs
and run the multitest.sh script:
../contrib/multitest.sh /FULLPATH/roi_pac_testdir.tar /FULLPATH/ROI_PAC_3_0_1/ROI_PAC/multibuild-xxxxxx-yyyy/installs/share/roi_pac /FULLPATH/ROI_PAC_3_0_1/ROI_PAC/multibuild-xxxxxx-yyyy/installs/BUILD1/bin  ... ... ... /FULLPATH/ROI_PAC_3_0_1/ROI_PAC/multibuild-xxxxxx-yyyy/installs/BUILDN/bin

where:
FULLPATH is the path to your home directory (or where ever the install is)
xxxxxx-yyyy is the multibuild date-time stamp
and BUILD1 to BUILDN are all the compilers sub directories in /FULLPATH/ROI_PAC_3_0_1/ROI_PAC/multibuild-xxxxxx-yyyy/installs/ e.g. defaults, gfortran, gfortran64 etc.

check for the fastest build by checking the batchlog files for each build in test-runs directory.

go to multibuild directory and into installs. get the bin directory from the desired compiler directory and copy it to the ~/ROI_PAC_3_0_1/ROI_PAC directory.

• note: I moved the bin directory to: ~/ROI_PAC_3_0/ROI_PAC/BIN/LIN

see the ROI_PAC Wiki - Installation for updated installation notes
look also at ROI_PAC Wiki for updates and patches.

now you can use ROI PAC, but keep in mined orbits and other auxiliary data should also be available for processing.