| | 1 | = Creation of DEMs from NextMap data = |
| | 2 | |
| | 3 | (fast notes) |
| | 4 | |
| | 5 | load arc files into grass |
| | 6 | * import->raster->gdal |
| | 7 | * pick file |
| | 8 | * choose create new location if this is the first import |
| | 9 | * run (will fail for UK as it needs user input) |
| | 10 | * copy and paste command into grass shell so you can respond (e.g. `r.in.gdal -e input=/data/aegean1/nextmap_dems/neodc/by_tile/by_product/dsm/nk/nk02/nk02dsm/w001001.adf output=nk02` |
| | 11 | * if you need to import multiple rasters, you can use the location created, but must select extend region |
| | 12 | * (need to figure out how to join rasters into one, then subset in grass) |
| | 13 | |
| | 14 | export as ASCII grid |
| | 15 | |
| | 16 | [you can load this grid into ENVI to test against vector layers, etc - file->open external->generic->ascii, then georeference (edit headers->mapinfo, etc)] |
| | 17 | |
| | 18 | edit ASCII file to have an azgcorr compatible header (first line must be as follows, then DEM data): |
| | 19 | {{{ |
| | 20 | -ed or c r xm ym xx yx gi : is the basic flat file ascii DEM definition |
| | 21 | : or = data order =0 rows S->N, =1 rows N->S |
| | 22 | : c = cols, r = rows, xm, ym = SW, xx, yx = NE corners |
| | 23 | : gi = grid increments; grid values separated by spaces |
| | 24 | : ** NB: for this definition georeferencing of the DEM grid is assumed |
| | 25 | : to be at the CENTRE of the cell defined by the grid coordinates |
| | 26 | : ** if this is NOTthe case use option -edx, below |
| | 27 | |
| | 28 | e.g. |
| | 29 | 1 2000 2000 400000 850000 410000 860000 5 |
| | 30 | N->s Xsize YSize Xmin Ymin Xmax Ymax grid size (5m for nextmap) |
| | 31 | }}} |
| | 32 | |
| | 33 | Use DEM with azgcorr -eh demfilename |