= Creation of DEMs from NextMap data = (fast notes) load arc files into grass * import->raster->gdal * pick file * choose create new location if this is the first import * run (will fail for UK as it needs user input) * 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` * if you need to import multiple rasters, you can use the location created, but must select extend region * (need to figure out how to join rasters into one, then subset in grass) export as ASCII grid [you can load this grid into ENVI to test against vector layers, etc - file->open external->generic->ascii, then georeference (edit headers->mapinfo, etc)] edit ASCII file to have an azgcorr compatible header (first line must be as follows, then DEM data): {{{ -ed or c r xm ym xx yx gi : is the basic flat file ascii DEM definition : or = data order =0 rows S->N, =1 rows N->S : c = cols, r = rows, xm, ym = SW, xx, yx = NE corners : gi = grid increments; grid values separated by spaces : ** NB: for this definition georeferencing of the DEM grid is assumed : to be at the CENTRE of the cell defined by the grid coordinates : ** if this is NOTthe case use option -edx, below e.g. 1 2000 2000 400000 850000 410000 860000 5 N->s Xsize YSize Xmin Ymin Xmax Ymax grid size (5m for nextmap) }}} Use DEM with azgcorr -eh demfilename ---------- = Command line method = Starting from a valid location (in correct projection?) {{{ # read in a tile r.in.gdal -e input=/data/aegean1/nextmap_dems/neodc/by_tile/by_product/dsm/tl/tl17/tl17dsm/w001001.adf output=tl17 # set the region of interest to the (two) tiles we want to export g.region rast=tl17,tl27 # patch them together into a single raster r.patch input=tl17,tl27 output=tl17and27 # write out as an ASCII DEM (needs editing as above) r.out.ascii input=tl17and27 output=/tmp/tl17and27.dem null=0 }}}