Script for Downloading NYS DHES LiDAR and Creating Contours and Hillshades
Here is a brief PHP script I use to download LiDAR data from NYGIS website. You simply supply it a list of quads on the command line like php getlidar.php u_3592573775_1m_DEM.img u_3600073175_1m_DEM.img
then execute the below script. This script requires PHP and the dbase extension. If you use PHP7, you can download a version of dbase for PHP7 .
#!/usr/bin/php -q array_shift($argv); // remove program name $lidarDir = "/home/andy/Documents/GIS.Data/lidar"; $tomerge = ""; $merged = ""; $conDir = "/tmp"; foreach ($argv as $quad) { $wgetCommand = "wget -c -P $lidarDir \"ftp://ftporthos.dhses.ny.gov/lidar/nysdop/dem/$quad\""; #echo "$wgetCommand\n"; system($wgetCommand); $tomerge .= "$lidarDir/$quad "; $merged = "merge".substr($quad,1,-4); } $mergeLidarCommand = "gdalwarp -co \"COMPRESS=LZW\" $tomerge $conDir/$merged.tif -r average -overwrite"; #echo "$mergeLidarCommand\n"; system($mergeLidarCommand); // produce hillshade system("gdaldem hillshade {$conDir}/{$merged}.tif {$conDir}/{$merged}hillshade.tif -z 2.0 -s 1.0 -az 315.0 -alt 45.0 -compute_edges"); // produce deeper hillshade system("gdaldem hillshade {$conDir}/{$merged}.tif {$conDir}/{$merged}hillshade.6x.tif -z 6.0 -s 1.0 -az 315.0 -alt 45.0 -compute_edges &"); $minor = 5; $major = 25; $minorMeters = $minor * 0.3048; $majorMeters = $major * 0.3048; // produce contours if (file_exists("{$conDir}/{$merged}{$major}ft-contour.shp")) { unlink("{$conDir}/{$merged}{$major}ft-contour.shp"); } if (file_exists("{$conDir}/{$merged}{$minor}ft-contour.shp")) { unlink("{$conDir}/{$merged}{$minor}ft-contour.shp"); } system("gdal_contour -a elev -i {$majorMeters} {$conDir}/{$merged}.tif {$conDir}/{$merged}{$major}ft-contour.shp"); system("gdal_contour -a elev -i {$minorMeters} {$conDir}/{$merged}.tif {$conDir}/{$merged}{$minor}ft-contour.shp"); // convert contour elevation to feet from meters foreach (array("{$conDir}/{$merged}{$minor}ft-contour.dbf", "{$conDir}/{$merged}{$major}ft-contour.dbf") as $file) { $db = dbase_open("$file", 2); if ($db) { $record_numbers = dbase_numrecords($db); for ($i = 1; $i <= $record_numbers; $i++) { // gets the old row $row = dbase_get_record($db, $i); // Update the date field with feet instead of meters $row[1] = ceil($row[1] * 3.280839); // remove the 'deleted' entry unset($row['deleted']); // replace record and save dbase_replace_record($db, $row, $i); } } dbase_close($db); }