| 194 | === Creating a DEM from LiDAR data using ''lidardem.sh'' script === |
| 195 | ==== Configuring lidardem.sh ==== |
| 196 | To run lidardem.sh on your system the files listed above need to be configured in the script to point to the correct places. |
| 197 | For example, the template grass database in the script points to a place in the arsf directory and this needs to be changed to point to where your template grass database is located. |
| 198 | Variables that need to be changed: |
| 199 | * TEMPLATE_GRASS_DATABASE=/users/rsg/arsf/usr/share/grass_db_template/ |
| 200 | * WGS84LL_SEPARATION_FILE=/users/rsg/arsf/dems/aster/separation_files/uk_separation_file_WGS84LL.dem |
| 201 | * GRASS_VERSION=grass63 |
| 202 | I would advise that the grass version be 6.3 as the script was written to work with this grass version. |
| 203 | |
| 204 | ==== Using asterdem.sh ==== |
| 205 | The script is partly configured to be used in-house and so some options that are available are not applicable, as for example the navigation file is used to calculate the tiles to use by default. So here is a usage for out of house usage: |
| 206 | |
| 207 | lidardem.sh[[BR]] |
| 208 | [[BR]] |
| 209 | Generates a binary LiDAR DEM from LAS/ASCII files[[BR]] |
| 210 | [[BR]] |
| 211 | Arguments:[[BR]] |
| 212 | -d: Directory containing LiDAR data[[BR]] |
| 213 | or[[BR]] |
| 214 | -f: LiDAR file to create DEM from[[BR]] |
| 215 | (Optional)[[BR]] |
| 216 | -h: Display usage and exit[[BR]] |
| 217 | -o: Final output filename for DEM, defulats to leaving in grass database[[BR]] |
| 218 | -c: Whether to use points of classification 7, defaults to just points of classification 1[[BR]] |
| 219 | -a: Whether to use all returns, defaults to using first return only[[BR]] |
| 220 | -r: Resolution to input LiDAR files with, defaults to 2[[BR]] |
| 221 | -R: Resolution to output LiDAR files with, defaults to calculating from input resolution[[BR]] |
| 222 | -j: Create a jpg image of the DEM[[BR]] |
| 223 | -g: Grass database to use, defaults to creating a GRASS database locally[[BR]] |
| 224 | -t: Whether to use ASCII files to create the DEM, defaults to using LAS files[[BR]] |
| 225 | -z: Specify an input projection[[BR]] |
| 226 | -p: Projection to output DEM in: proj4 string or UKBNG or ll or UTM[zero_padded_number](N|S)[[BR]] |
| 227 | -s: geoid-spheroid separation file[[BR]] |
| 228 | -m: Maximum size of output DEM in GB, will be overridden by specified resolution[[BR]] |
| 229 | -i: Navigation file to use[[BR]] |
| 230 | -N: North buffer, defaults to 2000[[BR]] |
| 231 | -S: South buffer, defaults to 2000[[BR]] |
| 232 | -E: East buffer, defaults to 2000[[BR]] |
| 233 | -W: West buffer, defaults to 2000[[BR]] |
| 234 | -F: Do not filter the DEM[[BR]] |
| 235 | -E: Extrapolate the DEM, followed by the resolution to extrapolate at[[BR]] |
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