====== Differences ====== This shows you the differences between two versions of the page.
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| There exist two sources for obtaining accurate orbits for the ERS satellites. The [[http://www.deos.tudelft.nl/|Delft | There exist two sources for obtaining accurate orbits for the ERS satellites. The [[http://www.deos.tudelft.nl/|Delft | ||
| - | Institute for Space-Oriented Space Research]] (DEOS) provides orbit information for both [[http://www.deos.tudelft.nl/ers/precorbs/|ERS and ENVISAT]]. An alternative source is the [[http://earth1.esrin.esa.it/f/eeo2.400/pgersorbprc|Precise Orbit Product]] through the [[http://www.esa.int/|European Space Agency]] (ESA). | + | Institute for Space-Oriented Space Research]] (DEOS) provides orbit |
| + | information for both [[http://www.deos.tudelft.nl/ers/precorbs/|ERS and | ||
| + | ENVISAT]]. An alternative source is the | ||
| + | [[http://earth1.esrin.esa.it/f/eeo2.400/pgersorbprc|Precise Orbit Product]] | ||
| + | through the [[http://www.esa.int/|European Space Agency]] (ESA). Download | ||
| + | instructions are posted [[orbits|here]]. This step does not have to be repeated once the orbit files are downloaded for a given scene. | ||
| ===== DEM Preparation ===== | ===== DEM Preparation ===== | ||
| - | In order to use the two pass method, a Digital Elevation Model (DEM) is | + | In order to use the two-pass method, a Digital Elevation Model (DEM) is |
| necessary to subtract out the topographic contribution from the | necessary to subtract out the topographic contribution from the | ||
| interferogram. Global DEM data can be obtained from the [[http://srtm.usgs.gov/|Shuttle Radar Topography Mission (SRTM)]]. | interferogram. Global DEM data can be obtained from the [[http://srtm.usgs.gov/|Shuttle Radar Topography Mission (SRTM)]]. | ||
| It can also be obtained indirectly from the SAR scenes using the three-pass | It can also be obtained indirectly from the SAR scenes using the three-pass | ||
| method. A detailed list of procedures that explain | method. A detailed list of procedures that explain | ||
| - | how to use SRTM data can be found here: [[srtm|Using SRTM data]]. | + | how to use SRTM data can be found here: [[srtm|Using SRTM data]]. This step does not have to be repeated once the DEM is created. |
| ===== ROI_PAC Processing ===== | ===== ROI_PAC Processing ===== | ||
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| This perl script runs a sequence of programs | This perl script runs a sequence of programs | ||
| that eventually produces your differential interferogram. | that eventually produces your differential interferogram. | ||
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| ===== Viewing Your Results ===== | ===== Viewing Your Results ===== | ||
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| ROI_PAC. You can | ROI_PAC. You can | ||
| use a variety of external programs to view your results (i.e. mdx, dgx, | use a variety of external programs to view your results (i.e. mdx, dgx, | ||
| - | Matlab, GMT, ENVI, or other program that is flexible enough to read a binary | + | [[:matlab|Matlab]], GMT, ENVI, or other program that is flexible enough to read a binary |
| image file). | image file). | ||
| After you view your results, you may choose to re-process your data | After you view your results, you may choose to re-process your data | ||
| with different initial [[:roipac:process:parameter|parameters]] or experiment with | with different initial [[:roipac:process:parameter|parameters]] or experiment with | ||
| some [[:advanced|advanced techniques]]. | some [[:advanced|advanced techniques]]. | ||
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