| Label | Explanation | Data Type |
Input 3D Features
| The 3D line features that will be used to generate the clearance zone. | Feature Layer |
Horizontal Clearance
| The horizontal displacement of the clearance zone from each side of the input features. | Linear Unit |
Vertical Clearance
| The vertical displacement of the clearance zone from each input feature. The direction of the vertical displacement is indicated by the Overlap Method parameter value. If the Lowest Clearance option is specified, the vertical displacement will be lower than the input features. If the Highest Clearance option is specified, the displacement will be higher than the input features. | Linear Unit |
Output Raster Surface
| The output raster surface that represents the clearance zone. | Raster Dataset |
Cell Size
| The cell size of the output raster surface. | Linear Unit |
Overlap Method
(Optional) | Specifies the method that will be used to define the clearance zone in places where the zone around multiple features overlap.
| String |
Flare Angle
(Optional) | The arithmetic angle that defines the direction of the flare at the end of the clearance zone. A positive value indicates the flare angle will extend upward, and a negative value indicates the flare will extend downward. | Double |
Flare Distance
(Optional) | The 3D length that will extend from the edge of the clearance zone along the direction provided by the Flare Angle parameter. A flare angle of 45° and a flare distance of 7 meters mean the edge of the clearance zone defined by its horizontal distance will extended by 7 meters at an upward angle of 45°. | Linear Unit |
Summary
Generates a raster surface modeling the clearance zone around 3D line features.
Illustration
Usage
A clearance zone represents the theoretical height of an area around a particular feature that is to remain clear of intrusions from other features. In the context of electric transmission lines, this zone can represent the area of maximum height that vegetation can reach to minimize the risk of fire or other hazards; any vegetation that is higher than the clearance zone will need to be trimmed. In the context of streets and sidewalks, the clearance zone can represent the lowest height that vegetation can encroach over the paths of vehicles, cyclists, and pedestrians to not compromise safety. For shipping channels, the clearance zone can represent the navigable path that must be cleared of any sedimentary deposits.
The clearance surface can be compared to a height surface modeling real-world measurements to determine where clearance zones are violated. You can use the Cut Fill tool to evaluate the two surfaces to determine the surface area and volume of each contiguous clearance zone violation. The height surface created from real-world measurements should reflect the directional bias of the clearance zone. For example, if the clearance zone defines the maximum height of a potential source of intrusion, as is the case with vegetation encroachment of powerlines or sedimentary deposits along shipping channels, the height surface created from real-world measurements should have a bias for maximum height values of trees and sedimentary depositions. Likewise, if the clearance zone defines the minimum height of a potential source of intrusion, such as vegetation around sidewalks and roadways, the height surface created from real-world measurements should have a bias for minimum height values. The height surface of real-world measurements in LAS data can be created using the LAS Dataset To Raster tool, and the Point Cloud To Raster tool can be used for I3S point clouds.
Use the Extract Power Lines From Point Cloud tool with the option to eliminate the effect of wind when generating power lines that will be used as input for modeling clearance zones. The position of points capturing power lines are usually distorted by the effect of wind, which can cause significant deviations in the position of the power line. Eliminating for the effect of wind results in the creation of power lines reflecting the normal path of the conductor cable.
If the clearance zone requires the incorporation of multiple raster surfaces modeling different types of clearance requirements, use the Mosaic To New Raster tool with the appropriate merge operator for the type of clearance being modeled.
Parameters
arcpy.ddd.GenerateClearanceSurface(in_3d_features, horizontal_clearance, vertical_clearance, out_surface, cell_size, {overlap_method}, {flare_angle}, {flare_distance})| Name | Explanation | Data Type |
in_3d_features | The 3D line features that will be used to generate the clearance zone. | Feature Layer |
horizontal_clearance | The horizontal displacement of the clearance zone from each side of the input features. | Linear Unit |
vertical_clearance | The vertical displacement of the clearance zone from each input feature. The direction of the vertical displacement is indicated by the overlap_method parameter value. If the MINIMUM option is specified, the vertical displacement will be lower than the input features. If the MAXIMUM option is specified, the displacement will be higher than the input features. | Linear Unit |
out_surface | The output raster surface that represents the clearance zone. | Raster Dataset |
cell_size | The cell size of the output raster surface. | Linear Unit |
overlap_method (Optional) | Specifies the method that will be used to define the clearance zone in places where the zone around multiple features overlap.
| String |
flare_angle (Optional) | The arithmetic angle that defines the direction of the flare at the end of the clearance zone. A positive value indicates the flare angle will extend upward, and a negative value indicates the flare will extend downward. | Double |
flare_distance (Optional) | The 3D length that will extend from the edge of the clearance zone along the direction provided by the flare_angle parameter. A flare angle of 45° and a flare distance of 7 meters mean the edge of the clearance zone defined by its horizontal distance will extended by 7 meters at an upward angle of 45°. | Linear Unit |
Code sample
The following sample demonstrates the use of this tool in the Python window:
import arcpy
arcpy.env.workspace = 'c:/data'
arcpy.ddd.GenerateClearanceSurface('VegManagement.gdb/PowerLines', '15 Meters',
'9 Meters', 'ClearanceZone.tif',
'50 Centimeters', 'MAXIMUM', 45, '5 Meters')