ROI_pac

Valerie SahakianLaura Sumiejski

SIO 23902/19/2010

What the heck is ROI_pac?

• Takes data• Gets offsets from 2 single-look complex (SLC)

images• Fits 2nd order polynomial to offsets• Resample SLC images (dates)• Multiply complex pixels of images

Gets amplitudes

But…

• Amplitudes form raw interferogram– Topography– Atmosphere– Orbit– Deformation– Etc.

Refine Model

• Removes phase from orbit geometry– Begins flattening

• Calculate correlation between 2 scenes• Removes topography– Calculates and removes phase from DEM

• Subtract models from seismic interferogram• Filter noise, mask (phase variance), unwrap,

etc.

Refine Model cont.

• Re-estimate baseline– Use topography to refine

• Geocoding– Unwrapped phase• Change coordinates over to geographical coordinates to

match DEM

Directory Hierarchy

• Data Directory– Data

• Run Directory– Copies of data– .proc file– DEM directory• DEM

Choose a Location!

• Use EOLi – Earth Observation Link from the European Space

Agency

• For our example we chose an area in Southern California– 35.6° N and 120.28° W• (about 36°36’ latitude and -120°18’ longitude)

Track 256

• Frame 2889• Date 1: Nov.

10, 1992• Date 2: May

17, 1996

Get the Data

• WInSAR– Western North America InSAR Consortium– Data for western US– Members only– Data on WInSAR– Data downloadable from GeoEarthScope and

Supersites

Inputs for ROI_pac: Raw Data

• For ERS1 and ERS2– Assign master and slave

• Master = SARLEADER• Slave = IMAGERY• Note: these files should have the date appended to the

end with the time stamp

– make_raw.pl• Outputs:

– Raw data: date.raw– Metadata for raw data: date.raw.rsc– Reformatted orbit data: hdr_data_points_date.rsc

Inputs for ROI_pac: Parameters

• DEM– Digital Elevation Model • SRTM data

– Mosaic_srtm.pl –Rw/e/s/n magic.DEM

• Process File (.proc)– Int_date2_date1.proc• Radar acquisition dates• Pathname for magic.DEM

But…

• On sioprism.ucsd.edu– /data/ERS1/track/frame/orbit/– /data/ERS2/track/frame/orbit/

• ERS2_track_frame_orbit.zip

• Copy desired data to your directory– Run ers2roi.pl

• Unzips files• Includes make_raw.pl• Makes master and slave files• Makes .proc file

Baseline

• Run base_roi.pl– Acceptable baseline pairs– Perpendicular and parallel baselines– Etc.

• Note: edit path for DEM in .proc file

process_2pass.pl

• Run <process_2pass.pl int_date2_date1.proc>• Wait ~ 1 hour• Magic happens!• To see interferogram– int_date2_date1/flat/ (from after flattening)– <mdx.pl file.unw>

• Note: make sure you ssh using –X or -Y

Success! (sort of)

References

• University of Oregon, WikiRoiPac. http://www.uoregon.edu/~das/WikiRoiPac/doku.php?id=welcome

• Fielding, Eric. ROI_pac Internals: Under the Hood, UNAVCO InSAR shortcourse. August 2009.