| | 1 | = Airborne Processing Library - Quick Start = |
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| | 3 | This is a short guide aimed at getting users geocorrecting their data straight away. For more in depth information please refer to the APL mapping user guide pdf. |
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| | 5 | == Creating an IGM file == |
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| | 7 | An IGM file is a file that contains per-pixel latitude, longitude and height information, and relates directly to the level 1 file. Using the data contained in an ARSF delivery this can be done using the following command for an Eagle image, where the level 1 data file is named {{{flightline1.bil}}} and the output IGM file will be called {{{flightline1.igm}}}. The DEM used is the ASTER DEM as provided with the hyperspectral delivery. |
| | 8 | |
| | 9 | {{{ |
| | 10 | aplcorr -lev1file flightlines/level1b/flightline1.bil -igmfile my_output/flightline1.igm -vvfile sensor_FOV_vectors/eagle_fov_fullccd_vectors.bil -navfile flightlines/navigation/flightline1_nav_post_processed.bil -dem dem/GB11_00-ASTER.dem |
| | 11 | }}} |
| | 12 | |
| | 13 | We now have per-pixel longitude and latitude values for the level 1 data of file {{{flightline1.bil}}}. But say we want to map the data to a different coordinate system. For this we need to re-project the IGM data. |
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| | 15 | == Reprojection from Geographic Latitude / Longitude == |
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| | 17 | Reprojection is done in APL using the apltran software. This uses the open source PROJ libraries for performing the reprojection. There are 2 projections that have quick keywords set up in apltran; Ordnance Survey National Grid (OSTN02) and WGS84 Universal Transverse Mercator (UTM). To reproject {{{flightline1.igm}}} into UTM Zone 31 we could do the following: |
| | 18 | |
| | 19 | {{{ |
| | 20 | apltran -inproj latlong WGS84 -igm my_output/flightline1.igm -output my_output/flightline1_utm31.igm -outproj utm_wgs84N 31 |
| | 21 | }}} |
| | 22 | |