Package opalsGeoref

The package opalsGeoref contains modules dealing with the adjustment (co-registration) of ALS flight strips or TLS scans. The relative fit of adjacent and overlapping ALS strips as well as the absolute orientation of the entire flight block is of crucial importance for subsequent application of ALS data. Therefore, OPALS provides a separate package concentrating on this issue.

Scripts and Modules of Package opalsGeoref
Python Scripts Description
grfApprox.py brief Computes a best fitting affine transformation for overlapping (strip) DEMs using Least Squares Matching.
grfExport.py Exports data considering previously computed transformations.
opalsGeoref.py Package script providing tools for geo-referencing and co-registration of ALS flight strips.
qltLSM.py Calculates best fitting 3d-affine transformations between overlapping strip pairs.
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.
Colorize
DirectGeoref Transforms points from scanner coordinates into geo-referenced coordinates by applying the sensor model (flight trajectory, mounting parameters).
Export Exports vector data stored in an OPALS data manager (ODM) in various data formats.
GeorefApprox Improves the geo-referencing of an ALS flight block based on pairwise affine strip transformations (cf. Module LSM).
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).
ICP Performs orientation (co-registration) of multiple point cloud datasets using the Iterative Closest Point algorithm.
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).
StripAdjust Improves the geo-referencing of ALS data and aerial images in a rigorous way combining strip adjustment and aerial triangulation.
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.