3D Analyst Tools ArcToolbox

Classify LAS By Height and Classify LAS Ground

Classify LAS By Height

How to use Classify LAS By Height Tool in Arc Toolbox ArcMap ArcGIS ??

Classify LAS By Height

Classify LAS Building Tool, LAS Dataset Toolset, Data Management Toolset, 3D Analyst Toolbox

 

Classify LAS By Height

Reclassifies lidar points based on their height from the ground surface.

1.    Input LAS Dataset

The LAS dataset that will be processed. Only LAS points with class code values of 0 and 1 will be evaluated.

2.    Ground Source

The source of ground measurements that will be used to determine height above ground.

· GROUND—LAS points designated with the ground classification code value of 2 and model key code value of 8 will be used.

· MODEL_KEY—Only LAS points designated with the model key classification code value of 8 will be used.

3.    Class Code

The class code and maximum height from ground that will be used to reclassify LAS points. The order of the classes in the table will define the range of Z values that will be used to process the reclassification. The first entry's Z-range will span from the ground surface to the specified Height From Ground value. The Z-range of subsequent entries will span from the upper limit of the preceding entry to its own Height From Ground value.

4.    Noise Classification (optional)

Indicates whether to reclassify points as noise based on their proximity from the ground. Noise artifacts in lidar data can be introduced by sensor errors and the inadvertent interception of aerial obstructions like birds in the path of the lidar pulse.

· ALL_NOISE—Both low and high noise will be classified.

· HIGH_NOISE—Only points that are above the maximum height in the LAS classification table will be reclassified as high noise.

· LOW_NOISE—Only points below the ground surface will be reclassified as noise. This is only available when all ground points are used to define the ground surface.

· NONE—No points will be reclassified as noise.

5.    Compute statistics (optional)

Specifies whether statistics should be computed for the LAS files referenced by the LAS dataset. Computing statistics provides a spatial index for each LAS file, which improves analysis and display performance. Statistics also enhance the filtering and symbology experience by limiting the display of LAS attributes, like classification codes and return information, to values that are present in the LAS file.

· Checked—Statistics will be computed.

· Unchecked—Statistics will not be computed. This is the default.

6.    Processing Extent (optional)

Specify the extent of the data that will be evaluated by this tool.

7.    Processing Boundary (optional)

A polygon feature that defines the region for which LAS ground points will be evaluated.

8.    Process entire LAS files that intersect extent (optional)

Specify how the processing extent is applied.

· Unchecked—Only LAS points that are within the processing extent will be evaluated. This is the default.

· Checked—All points in the LAS files that intersect the processing extent will be evaluated.

Classify LAS Ground

How to use Classify LAS Ground Tool in Arc Toolbox ArcMap ArcGIS ??

Classify LAS Ground

Classify LAS Ground Tool, LAS Dataset Toolset, Data Management Toolset, 3D Analyst Toolbox

 

Classify LAS Ground

Classifies ground points in aerial lidar data.

1.    Input LAS Dataset

The LAS dataset to process. Only the last return of LAS points with class code values of 0, 1, and 2 will be evaluated.

2.    Ground Detection Method (optional)

The method used for detecting ground points.

· STANDARD—This method has a tolerance for slope variation that allows it to capture gradual undulations in the ground's topography that would typically be missed by the conservative option but not capture the type of sharp reliefs that would be captured by the aggressive option. This method is the default.

· CONSERVATIVE— When compared to other options, this method employs a tighter restriction on the variation of the ground's slope, which allows it to differentiate the ground from low-lying vegetation such as grass and shrubbery. It is best suited for topography with minimal curvature.

· AGGRESSIVE— This method detects ground areas with sharper reliefs, such as ridges and hill tops, that may be ignored by the Standard method. This method is best used in a second iteration of this tool with the Reuse existing ground parameter enabled. Avoid using this method in urban areas or flat, rural areas, as it may result in the misclassification of higher objects—such as utility towers, vegetation, and portions of buildings—as ground.

3.    Reuse existing ground (optional)

Specifies if existing ground points should be reclassified or reused.

· Unchecked—Existing ground points will be reclassified. Points that are not found to be a part of the ground will be re-assigned a class code value of 1, which represents unclassified points. This is the default.

· Checked—Existing ground points will be accepted without scrutiny and contribute to the determination of unclassified points.

4.    DEM Resolution (optional)

Specifies a distance that will result in only a subset of points being evaluated for classification as ground, thereby making the process faster. Consider using this option when a faster method for generating a DEM surface is needed. The minimum distance is 0.3 meters, but the specified distance must be at least 1.5 times the average point spacing of the lidar data for this process to take effect.

5.    Compute statistics (optional)

Specifies whether statistics should be computed for the LAS files referenced by the LAS dataset. Computing statistics provides a spatial index for each LAS file, which improves analysis and display performance. Statistics also enhance the filtering and symbology experience by limiting the display of LAS attributes, like classification codes and return information, to values that are present in the LAS file.

· Checked—Statistics will be computed.

· Unchecked—Statistics will not be computed. This is the default.

6.    Processing Extent (optional)

Specifies the extent of the data that will be evaluated by this tool.

7.    Processing Boundary (optional)

A polygon feature that defines the area of interest to be processed by this tool.

8.    Process entire LAS files that intersect extent (optional)

Specifies how the area of interest will be used in determining how LAS files will be processed. The area of interest is defined by the Processing Extent, the Processing Boundary , or a combination of both.

· Unchecked—Only LAS points that intersect the area of interest will be processed. This is the default.

· Checked—If any portion of a LAS file intersects the area of interest, all the points in that LAS file, including those outside the area of interest, will be processed.