Figure 75: Bare Earth Extraction Expanded Extraction Parameters (Method 2)
Max. building size (length)
The length of the largest building in the image. The default is 100 meters.
Max. height to jump for region growing
The maximum distance to jump in the Z direction for the region growing process. The region growing process extracts more ground points from the initial seed ground points. The higher the jump distance the more the number of points that are higher in elevation will be collected. The default is 0.35 meters.
Max. slope of ground regions
The maximum slope within the regions that were extracted as ground. Any regions with slope greater than the maximum slope will be filtered out. The default is 45 degrees.
Number of iterations for bare earth extractions
The number of iterations for the bare earth extraction to extract probable ground points. The default is 2.
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Minimum area of extracted ground regions
The minimum area of extracted ground regions. Any regions smaller than this will be filtered out. The default is 30 square meters.
Ground Parameters
Sample 1 point in ground regions for every <value> (Method 1 and Method 2)
Defines the sampling rate of ground points. At least one ground point will be extracted for each window of this size within the ground regions. The default is 9 square meters.
Output last return if elevation difference between last return and ground surface estimate is (Method 1 and Method 2)
If the distance between the last-return (or single return) DEM and the extracted bare earth is lower than this threshold, then that region will be replaced with values from the last-return DEM. This step adds fidelity to the extracted bare earth. If this value is set to 0, then the output bare earth will be the original interpolated bare earth with post-processing clean-up applied. The default is 0.5 meters.
Masking Tab - Bare Earth Extraction Dialog
The Masking tab located in the Bare Earth Extraction dialog (expanded view) is used to select layers to mask.
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Bare Earth Modification Settings Dialog
The Bare Earth Modification Settings dialog can be used to verify layer you wish to edit. If needed, you can change the layers.
Access Location:
LIDAR Analyst
Toolbar: LIDAR Analyst Bare Earth
Command: Delete Points from Bare Earth
Doc Id: 9994
Figure 77: Bare Earth Modification Settings
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Bare Earth Modification Settings Options
Ground Points Layer
Allows you to choose the ground points layer.
Ground Mask Layer
Allows you to choose the ground mask layer.
Ground Mask Edits
Allows you to choose the ground mask edits layer.
Refresh Layer Lists
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Building Extraction Dialog
The Building Extraction dialog is used to se building removal parameters when running an extraction. For example, you can specify that any buildings with an area more than 30 square meters be removed. In addition, you can remove buildings by minimum and maximum height, as well minimum and maximum roof slope. From this dialog, you can launch the Square-Up dialog.
Access Location:
LIDAR Analyst
Menu (LIDAR Analyst Toolbar): LIDAR Analyst > Extraction
Toolbar: LIDAR Analyst
Command: Extract Buildings
Doc Id: 10107
Figure 79: Building Extraction Dialog
There are two building extractions dialogs with the similar options.
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Buildings Extraction Options
Bare earth
Displays the bare earth file for the building extraction.
Single/last return
Displays the single/last return field.
First return
Displays the First Return field.
Horizontal units
Displays the horizontal units for the buildings extraction including Unknown, Inches, Feet, Miles, Centimeters, Meters, Kilometers, Decimal Degrees, Minutes, Seconds, and Radians.
Vertical units
Displays the vertical units for the buildings extraction including Unknown, Inches, Feet, Miles, Centimeters, Meters, and Kilometers.
Extraction Method
Method 1 – Use this raster-based option to extract buildings from the bare earth raster.
This is the original building extraction algorithm.
Method 2 – If the bare earth was generated from a point cloud, use this option to extract
buildings directly from that point cloud. This approach works especially well with small building footprints.
Building output
Displays the name for the building output for the building extraction.
Reset to defaults
Resets all building extraction settings to the default settings.
<< Less button
Hides the Method 1, Method 2, Post-Process, and Square-Up tabs.
>> More button
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Building Tool Settings Dialog
The Building Tool Settings dialog is used to configure auto-split, reshape and reorient, and courtyard cleanup tools. These options are organized one three separate tabs.
Access Location:
LIDAR Analyst
Toolbar: LIDAR Analyst Building Edit
Commands: Building Edit Tool Options, Building Auto-Split, Building Reshape, Courtyard Cleanup. and Building Reorient.
Figure 81: Building Tool Settings Dialog
Building Tool Settings Options
Bare earth
Sets the path to bare earth image.
Building layer
Displays the name of the selected building layer.
Refresh Layers
Refreshes all images and layers displayed to reflect the selected images and layers.
Show Settings
Expands to displays settings.
Single/last return
Displays the name of the selected single/last return image.
First return
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