Feature Class To Coverage (Conversion)
Summary
Creates a single ArcInfo Workstation coverage from one or more input feature classes or layers.
Usage
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The cluster tolerance acts the same as the fuzzy tolerance in ArcInfo Workstation. The fuzzy tolerance of the output coverage will be the same as the cluster tolerance specified when executing this tool. If no cluster tolerance is specified, a default is calculated.
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Coverages do not support null geometries. Null geometries will be dropped during conversion.
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When one line feature class is entered as input, you can choose to build a coverage for arcs or routes. If the output contains a route subclass, it will be prefixed by ROUTE (for example, ROUTE.streets). The default type is ROUTE.
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When one polygon feature class is entered as input, you can choose to build a coverage for polygons or regions. If the output contains a region subclass, it will be prefixed by REGION (for example, REGION.parcels). The default type is REGION.
The default precision of the output will be DOUBLE.
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It is suggested you run the Create Labels tool after successfully executing this tool to ensure all polygon features have an accurate label.
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If one point feature class and one polygon feature class are entered as inputs, the point feature class can represent labels for the output coverage. To do this, choose LABEL as the type of features for the input points.
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When more than two line feature classes or layers are entered, only one of the feature classes can have arcs built in the output coverage. The remaining feature classes will contain routes.
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When more than two polygon feature classes or layers are entered, only one of the feature classes can have polygons built in the output coverage. The remaining feature classes will contain regions.
When converting a polygon feature class with overlapping polygons, discontiguous polygons, or "donut holes", you should convert the feature class to a region coverage. If you convert such a feature class to a polygon coverage, any overlapping polygons, discontinuous polygons, or "donut holes" will be lost or changed because those types of geometries are not permitted in polygon coverages.
In a line feature class, there is no effective limit to the number of vertices that can exist in a single line feature. In the ArcInfo Workstation coverage data model, a line is defined by 500 vertices. At the 500th vertex, the vertex automatically becomes a node, and a new line is started. When a line feature class is converted to a coverage, the attributes of the lines are stored in the ROUTE subclass. In order to transfer those attributes to the individual lines in the coverage, you can run the ArcInfo Workstation command ROUTEARC at the ArcInfo Workstation command line. This command transfers the attribute from the route, with its' unlimited vertices, to each segment of the entire line in the coverage, each of which is 500 vertices long.
Syntax
| Parameter | Explanation | Data Type |
in_features [[Featureclass, {Type}],...] |
The input feature classes or layers used to create a single ArcInfo Workstation coverage, including the type of features of which the coverage will be composed.
| Value Table |
out_cover |
The output coverage to be created. | Coverage |
cluster_tolerance (Optional) |
The minimum distance separating all feature coordinates (nodes and vertices) as well as the distance a coordinate can move in X or Y (or both). You can set the value to be higher for data that has less coordinate accuracy and lower for datasets with extremely high accuracy. | Linear unit |
precision (Optional) |
The precision of the output coverage.
| Boolean |
Code Sample
The following Python window script demonstrates how to use the FeatureclassToCoverage function in immediate mode.
import arcpy
from arcpy import env
env.workspace = "C:/data"
arcpy.FeatureclassToCoverage_conversion(
[["Montgomery.gdb/Landbase/parcels", "REGION"]],
"C:/output/mont_parcel", "", "")
The following stand-alone script demonstrates how to convert several related feature classes to one coverage. After the conversion finishes, the CreateLabels tool is run to correct the polygon labels in the output coverage.
# Name: FeatureclassToCvoerage_Example.py
# Description: Converts several featureclasses to one coverage
# Import system modules
import arcpy
from arcpy import env
# Set environment settings
env.workspace = "C:/data"
# Set local variables
inFeatures = [["Montgomery.gdb/Landbase/blocks", "POLYGON"],
["Montgomery.gdb/Landbase/parcels", "REGION"],
["Montgomery.gdb/Landbase/Road_cl", "ROUTE"],
["Montgomery.gdb/Landbase/RoadNames", "ANNO"],
["Montgomery.gdb/Water/Transmains", "ARC"]]
outCover = "C:/output/Montgomery"
clusterTolerance = 0.000656
precision = "DOUBLE"
# Execute FeatureclassToCoverage and CreateLabels
arcpy.FeatureclassToCoverage_conversion(inFeatures, outCover,
clusterTolerance, precision)
arcpy.CreateLabels_arc(outCover, "")