SELECT POINTS ON THE BASIS OF A GEOTIFF FILE WITH THE POINTCLOUD CLASS
In this tutorial an Airborne Laserscanning (ALS) point cloud is filtered with the GeoTiff selection strategy.
Contents
Note: You can extract the code from this html file with the matlab function grabcode
Example script
Note: you have to download the point cloud used within this example from the website.
% Import all 4.5 million points from a laz file pc = pointCloud('ALS_strip.laz'); % Plot all points of point cloud pc.plot('Color' , 'A.intensity', ... % plot intensity of points 'ColorMapName', 'gray'); % use gray colomap title('All Points', 'Color', 'w'); snapnow; % Select points within all cells with value = 1 of the specified GeoTiff file path2geoTiff = 'stable_areas.tif'; minMax = [1 1]; pc.select('GeoTiff', path2geoTiff, minMax); % Plot only the selected points close; % close previous figure pc.plot('Color' , 'A.intensity', ... 'ColorMapName', 'gray'); title('Points selected with GeoTiff file (= stable areas)', 'Color', 'w'); % Export selected points to ascii file (without attributes) pc.export('ALS_strip_stable_areas.xyz');
As can be seen in the following image, the points are selected exactly within the white cells (value = 1) of the GeoTiff file (screenshot from SagaGIS).