Package opalsQuality

The package opalsQuality contains various modules for checking the quality of ALS point clouds. The aim of this package is to get a simple and fast overview about the captured terrain data and their quality. Among the features of interest are: digital surface models (DSM), point density maps, ALS strip
differences for checking the relative accuracy, differences to control-patches in order to check the absolute accuracy and similar. The final goal is to provide a professional basis for the checking and documentation of the quality of ALS data and for decision making on further pre-processing like strip adjustment.

Scripts and Modules of Package opalsQuality
Python Scripts Description Package script providing a complete processing chain for quality assessment of ALS flight strips. Performs absolute accuracy checks for entire flight blocks w.r.t. to (ground) control points. Derives surface models, shaded relief maps, and color coded hypsometric maps for a set of ALS strips. Derives point density maps (color coded raster maps) for a set of ALS strips. Calculates best fitting 3d-affine transformations between overlapping strip pairs. Derives relative strip difference maps (color coded raster maps) for a set of overlapping strip pairs. Script to combine a height coloring with a hill shading.
Modules Description
Algebra Provides a generic raster algebra calculator featuring mathematical, statistical and conditional operators.
Bounds Derives and stores the 2D boundary polygon of a region covered by the point data of an ODM or the valid pixels of a raster.
Cell Calculates statistical features of user defined attributes and stores them as raster models or rasterized point clouds.
Diff Calculates a difference grid model based on either two grids or a one grid and a horizontal reference plane.
Export Exports vector data stored in an OPALS data manager (ODM) in various data formats.
Grid Derives a 2.5D digital elevation models (DEM) in regular grid structure using simple interpolation techniques.
Histo Derives histograms and descriptive statistics (min, max, mean, r.m.s, etc.) for ODM or grid/raster data sets and stores the results graphically (SVG) and numerically (XML).
Import Loads vector and raster data into an ODM for subsequent use in modules dealing with point cloud and line related data.
Info Extracts and reports header information of a vector or raster file (ODM, GDAL).
LSM Estimates an affine 3D transformation to align overlapping ALS strip DEMs using Least Squares Matching.
Overlap Analyses a set of strip boundaries and determines all overlapping strip pairs.
Rasterize Performs vector-to-raster conversion for all types of simple feature geometries (points, lines, polygons).
Shade Derives shaded relief raster maps (geo-coded hill shading) of DEM grids.
Translate Performs format conversion for vector data files with additional read support of GDAL rasters.
Vectorize Performs raster-to-vector conversion and exports polyline geometries.
View Provides an interactive 3d viewer for points (including arbitrary attributes) and lines.
ZColor Derives color coded visualizations of grid models and stores them as geo-coded raster images.