This page provides information about questions that are (in our experience) frequently asked about EV-InSAR. We suggest users visit this page first before they contact Atlantis Scientific Technical Support. If you can not find the answers to your questions below, you can request technical support by one of the following methods:

• Call Atlantis InSAR tech support phone number 1-613-727-1087
• Mail to Atlantis InSAR tech support techsupport@atlantis-scientific.com
• Submit a technical support request form from http://www.atlantis-scientific.com/techsupport_form.html

EV-InSAR v2.1.3 Frequently Asked Questions

My run has failed, what should I do?

• Please make sure you are running the most recent version of EV-InSAR. Upgrades and patch releases are normally announced via e-mail to maintenance customers.
• The first thing to do is examine the error message and determine what processing step the run failed on. In many cases this will relate to an issue described below.

• No, only 16-bit integer formats are supported. More information may be found in the EV-InSAR users manual.

• This is no longer done from the "Select input data" options menu. There is a tool available from the InSAR GUI "Utilities" menu called "Orbit Manager". More detailed information can be found in section 10.4.1 of the EV-InSAR v2.1.2 users manual.

• This is done using the "Image Conversion" tool which is launched from the "Utilities" menu on the EV-InSAR main GUI. Details about how to use this tool can be found in section 10.4.2 of the EV-InSAR v2.1.2 users manual.

• This subject is too detailed to fit within the scope of an FAQ. The details may be found in section 9.1.7 of the EV-InSAR v2.1.2 users manual.

• In general, whatever geocoded DEM formats are supported by OpenEV are supported by EV-InSAR, with the exception of the JDEM format (please see next item). OpenEV's format support is based on the Geospatial Data Abstraction Library (GDAL); for more information on GDAL, see http://www.remotesensing.org/gdal/. Certain formats require additional libraries and are not built into the version of GDAL shipped with our products. As of OpenEV 1.6, a list of the formats that have been built in can be accessed through OpenEV's "Help->Formats" menu entry. This will launch an interface with "Atlantis-Supported" and "Unsupported" lists. The formats falling under the "Atlantis-Supported" list are regularly used at Atlantis and are supported; those falling under "Unsupported" are provided but may not be tested and are not supported. Note that although "Japanese DEM" is on the "Unsupported" list because it is not extensively tested, it is supported for import into EV-InSAR (please see next item) and reported problems will be investigated. Within the Formats interface, placing the mouse over a format entry should pop up a box indicating which datatypes are recognized for that format. If html information is available for that format, pressing the "Help" button should launch a browser with the relevant html page loaded. The full path to a working html browser must be specified in OpenEV's preferences for the html help to launch properly (see the "Help Browser" tab under the "Edit->Preferences" menu entry in OpenEV).
• Yes, using the "JDEM Tool" which is launched from the "Utilities" menu on the EV-InSAR main GUI. Details about how to use this tool can be found in section 10.4.3 of the EV-InSAR v2.1.2 and later users manual.

• Unfortunately, there is not a single cause for this problem. Sometimes poor bias detection or areas of low correlation between the two images can affect coregistration. The following are recommended approaches: -Turn off automatic bias detection, or specify a manual bias. -Increase the number of tiepoint patches, i.e. from a grid of 8X8 to 16X16. -In severe cases, the manual tiepoint editor can be used to manually mark tiepoints.

Please refer to section 12.1.5 of the EV-InSAR v2.1.2 users manual for more details.

• In cases where the external DEM is significantly smaller than the specified region of interest, the number of grid points may need to be increased. In some cases a bias point might need to be specified such as when orbital accuracy is not sufficient.

• The reference section of the EV-InSAR user's manual is organized roughly in the same order as the EV-InSAR GUI from chapter to chapter. There are tables describing what the input options mean and sections describing major tool functionalities.

• The residual phase tools change the Slave State Vector geometry based on these inputs. BPerp is the perpendicular baseline between the Master and Slave scenes and Yaw literally refers to the Yaw of the Slave sensor platform.

• The intention of the tools is to adjust the phase interactively and attribute the change to an orbital error. Clearly, these two corrections should be physically linked and are not at present. Perhaps we have an uncompensated system error. We plan to pursue further R&D; in this area with a goal of treating these two types of phase corrections simultaneously.

• No, as of the EV-InSAR v2.1.2 release, the above files are no longer needed.

• You get this message because your EV-InSAR has not been authorized, has an expired license, or your system hardware configuration has changed. In any of these cases, you should contact Atlantis.

• Make sure you have the latest version of EV-InSAR (including patch releases). You may obtain these from the downloads site. If this is not the case it should be noted that trying to combine an ascending scene with a descending scene can cause this error. Also, combining an EV-APP processed scene with an ESRIN formatted scene may cause this if the data is not in the same orientation in both datasets. Two scenes that have no overlap as predicted by the orbital information may also cause this error.

• The view has a limited amount of memory "cache" for image display. The image layers share this resource. The OpenEV preferences allow the amount of cache space to be increased. Removal of some images from the layer dialog may be necessary in cases where memory is limited.

• No, the software now expects the relevant external run imagery files themselves to be specified in the 4-pass case, just as in the 2-pass case. Note that if you specify the external DEM, the GUI automatically detects the other relevant images from the external run.