Use the same vertical coordinate system for the surface as the LAS dataset. When the ground height is defined by a surface, the smallest z-value along the polygon's boundary will define the building's base height. Run the Add Surface Information tool with the input features set to the building footprint polygon, the input surface set to the ground-filtered LAS dataset, and the output property set to the Z_MIN value to ensure that the building goes to the lowest z-value.Filter the LAS dataset for ground points using the layer properties or the Make LAS Dataset Layer tool.The ground height can be attributed to the building footprint polygons in the following ways: If the height in the attribute table is expressed in a different linear unit, use the Calculate Field tool to apply the appropriate conversion factor before using this tool. When the ground height is derived from a field in the footprint polygon's attribute table, its height units are assumed to be the same as the z-unit of the input LAS dataset. If such features exist in the input data, you can make a copy of those features and replace the arc geometries with line segments using the Densify tool. Polygons containing arc segments are not supported by this tool. If the point cloud being processed has a high density of points, consider using the Sampling Resolution parameter to thin the points that will be used for constructing the rooftop. The Ground Height parameter value can be specified as either a field in the footprint polygon's attribute table or an elevation surface. The footprint is incorporated into this TIN as a clip polygon whose height is defined by the source specified in the Ground Height parameter. The building model is generated by constructing a TIN from the LAS points that overlap the building footprint polygon. Use the Classify LAS Ground tool to assign ground points with a class code value of 2 if they have not been classified previously. Generate the model once you are satisfied with the classification's coverage of buildings.Ĭlassify ground points before executing this tool. Review the result of the classification and make any necessary corrections by running the tool again with different parameter choices or through interactive classification editing. The tool will assign a class code value of 6 for points representing building rooftops. If building classified points are not present in the LAS dataset, use the Classify LAS Building tool to classify them. For best results, exclude points that represent portions of buildings other than the roof, as they generally add noise to the resulting building model. It is presumed that the LAS points provide a desirable coverage of the building rooftop.
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