LIS Arithmetic - calculations in 2D and 3D

This package contains tools for grid and point cloud arithmetics, including point cloud attribute calculations, height normalization, multitemporal change detection, and corridor mapping (vegetation encroachment).

Tool: Calculate Features from Fitted Plane

• calculation of features from a plane fitted into the neighborhood of the central cell of a moving window
• least-squares plane fitting by using the elevations of all grid cells within a specified radius
• calculated features: slope, aspect, standard deviation, elevation difference between central cell and plane, deviation from plane
• grid analysis based on plane fitting, e.g., terrain roughness

Tool: Create Difference Grid

• calculation of the difference between two input grids
• automatic color classification of the difference grid with various options
• change detection / multitemporal analyses
• quality control, e.g., flight strip adjustment

Tool: Create nDSM

• calculation of a normalized digital surface model (nDSM) from DSM and DTM
• several options on how to handle negative values in the output grid resulting from discrepancies between the DSM and DTM datasets
• creation of normalized DSM or canopy height model (CHM)

Tool: Distances between classified Points

• calculation of the shortest euclidean distance between points of one class and points of another class within a point cloud
• distance calculation both in 2D and 3D, 2D distance can be calculated horizontally and vertically
• determination of the distance between points, e.g., between points on powerlines and vegetation points (vegetation encroachment)
• corridor mapping / clearance

Tool: Examine Excavation

• calculation of various volumes from a reference measurement grid, a subsequent measurement after excavation, and a proposed surface (output table)
• optional usage of horizontal and vertical tolerances in order to estimate paid and unpaid overbreakage
• output of a difference grid and a grid showing areas missing excavation
• examination of the result of an excavation with regard to the proposed surface
• inclusion of vertical and horizontal tolerances to calculate the paid and unpaid overbreakage and the billable volume
• visualization of areas missing excavation

Tool: Invert Grid

• inversion of a grid dataset
• the inverted grid shares the same value range as the input grid, i.e. the maximum value of the input grid will become the minimum value of the input grid in the inverted grid and vice versa
• data processing, e.g., application of hydrological tools to DSMs

Tool: Point Cloud Attribute Calculator

• calculation of a new attribute value per point based on existing attributes of that point and a mathematical expression
• support of various operators, including trigonometric functions, boolean expressions, and if-else statements
• calculation of new attributes, e.g., ratios
• thresholding, reclassification, masking

Tool: Point Cloud Elevation Difference (Point to TIN 2D)

• calculation of the elevation differences between points of point cloud A and a TIN created from point cloud B
• distance is reported as the minimum distance and/or the distance along the plumb line
• optional output of measurement vector components (x,y,z)
• change detection / multitemporal analyses, e.g., quantification of erosion and deposition heights
• quality control, e.g., flight strip adjustment

Tool: Volume Difference

• calculation of the volume difference between two input grids
• total change in volume and cut-and-fill volumes are reported in a table
• difference grid, either with elevation or volume differences per grid cell)
• cut-and-fill analyses
• e.g., stock pile volumes, sedimentation

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