ArcMap

Calculate Bridge Overrides

Summary

Calculates the overrides necessary to properly display bridge representations at a given location.

Overrides can be calculated for either line or point bridge features. For a line bridge feature, an override will be calculated for the width of a bridge representation based on the overpassing feature representation that runs through the bridge.

For point bridges, overrides include

  • The rotation angle of a bridge representation based on its overpassing feature
  • The position of the bridge, if the original position is not coincident with the overpassing feature

Usage

  • This tool is meant to be used on Topographic Map (TM)-style datasets and requires a well-defined representation structure for point and line bridges.

  • A progress indicator displays during calculation. You can cancel the tool execution at any point. However, canceling only stops further execution; it does not undo any overrides that have already been written.

  • This tool works inside and outside edit sessions. If you are already in an edit session, you will be able to undo overrides that have been created.

  • This tool should not be confused with the Create Overpass tool in the Cartography toolbox. The Create Overpass tool generates new bridge features at the intersection of other features; this tool symbolizes existing features.

Syntax

arcpy.defense.CalculateBridgeOverrides(in_bridge_features, in_overpassing_features, reference_scale, {search_dist}, {expand}, {offset}, {min_length}, {bridge_subtype}, {overpassing_subtype})
ParameterExplanationData Type
in_bridge_features
in_bridge_features

The feature layer that contains the bridge features on which the overrides are calculated.

Layer
in_overpassing_features
in_overpassing_features

The feature layer that contains the features overpassing the bridges.

Layer
reference_scale

Defines the scale at which symbols appear at their intended size.

Long
search_dist
(Optional)

This is the distance by which this tool will buffer point bridge features when identifying the overpassing features, calculated in map units. This parameter is only available for point bridges. The default value is 0 meters.

Linear unit
expand
(Optional)

Indicates whether or not this tool considers marker layers on overpassing representations when analyzing widths.

  • NO EXPAND —Does not consider marker layers on overpassing representations. This is the default.
  • EXPAND —Considers marker layers on overpassing representations when analyzing widths.
Boolean
offset
(Optional)

The optional value that can be added to the bridge width override. The default value is 0 points.

Linear unit
min_length
(Optional)

The optional value that sets the minimum length of a line bridge. The default value is 1.35 millimeters.

Linear unit
bridge_subtype
(Optional)

The subtype of the feature class from the in_bridge_features parameter that will be modified by this operation.

String
overpassing_subtype
(Optional)

The subtype of the feature class in the in_overpassing_features parameter that will be used in this operation.

String

Code sample

CalculateBridgeOverrides example (stand-alone script)

The following code sample demonstrates how to use the CalculateBridgeOverrides tool.

# Name: CalculateBridgeOverrides_Example.py
# Description: Calculates the overrrides to display bridges properly at a location
# Requirements: ArcGIS Defense Mapping solution

# Import arcpy module
import arcpy
from arcpy import env

# Check out a DefenseMapping extension license
arcpy.CheckOutExtension("defense")

# Set Cartography environment settings
env.cartographicCoordinateSystem = "GEOGCS['GCS_WGS_1984',DATUM['D_WGS_1984',SPHEROID['WGS_1984',6378137.0,298.257223563]],PRIMEM['Greenwich',0.0],UNIT['Degree',0.0174532925199433]]"
env.referenceScale = "10000"

# Local variables:
inBridgeFeatures = "C:/Data/Layers/Bridge.lyr"
inOverpassingFeatures = "C:/Data/Layers/Railroad.lyr"
refScale="1000"

# Execute Calculate Bridge Overrides function
arcpy.CalculateBridgeOverrides_defense(inBridgeFeatures, inOverpassingFeatures, refScale)

# Check in the Defense Mapping extension
arcpy.CheckInExtension("defense")

Environments

Licensing information

  • Basic: No
  • Standard: Requires Defense Mapping
  • Advanced: Requires Production Mapping and Defense Mapping and Spatial Analyst

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