Check Geometry (Data Management)
Release 9.2 Last modified November 29, 2010	Print all topics in : "Tools"

Inspects each feature's geometry for problems. Valid input formats are shapefile and feature classes stored in a personal geodatabase or file geodatabase. SDE Geodatabases automatically check each geometry's validity when it is uploaded, therefore the Check and Repair Geometry tools are not for use with SDE.

Usage tips

• The Output table will have one record for each problem found. If no problems are found, the Output table will have no records.

• The Output table has the following fields:

  • CLASS — The full path to and name of the feature class in which the problem was found.
  • FEATURE_ID — The Feature ID (FID) or Object ID (OID) for the feature with the geometry problem.
  • PROBLEM — A short description of the problem.

• The PROBLEM field will contain one of the following:

  • Short segment — Some segments are shorter than allowed by the system units of the spatial reference associated with the geometry.
  • Null geometry — The feature has no geometry or nothing in the SHAPE field.
  • Incorrect ring ordering — The polygon is topologically simple, but its rings may not be oriented correctly (outer rings - clockwise, inner rings - counterclockwise).
  • Incorrect segment orientation — Individual segments are not consistently oriented. The "to" point of seg i should be incident on the "from" point of seg i+1.
  • Self intersections — The interior of each part must not intersect itself or other parts. For a multipoint geometry, this means two of the points in the multipoint are in the same location (same x and y coordinate).
  • Unclosed rings — The last segment in a ring must have its "to" point incident on the "from" point of the first segment.
  • Empty parts — The geometry has multiple parts, and one of them is empty (has no geometry).

• For multipoint features, only the null geometry and empty part problems apply.

• For point features, only the null geometry problem applies.

• The problem identified by this tool can be fixed in the following ways:

  • Editing the feature class with the geometry problem and fixing each individual problem identified. Some of the problems, such as nonsimple geometry, can not be fixed in the Editor.
  • By running the Repair Geometry tool on the feature classes that were identified as having geometry problems.

• The following environment setting affects this tool: Extent.

• To facilitate the review of the features which are reported to have geometry problems, in ArcMap you can join the input features to the output table using the Join tool. Simply join using the input's ObjectID field, and the output table's FEATURE_ID field. You may also uncheck the "Keep All" option so that only features with geometry problems are displayed.

Command line syntax
An overview of the Command Line window
CheckGeometry_management <in_features;in_features...> <out_table>

Parameter	Explanation	Data Type
<in_features;in_features...>	One or more feature classes or feature layers that will be checked for geometry problems. Valid input formats are shapefile and feature classes stored in a personal geodatabase or file geodatabase.	Feature Layer
<out_table>	The table that will contain the list of problems that were discovered.	Table

Data types for geoprocessing tool parameters

Command line example

workspace c:\ws\St_Lucia.mdb
CheckGeometry (contours ; roads ; vegetation ) CGResult

Scripting syntax
About getting started with writing geoprocessing scripts
CheckGeometry_management (in_features, out_table)

Parameter	Explanation	Data Type
in_features (Required)	One or more feature classes or feature layers that will be checked for geometry problems. Valid input formats are shapefile and feature classes stored in a personal geodatabase or file geodatabase.	Feature Layer
out_table (Required)	The table that will contain the list of problems that were discovered.	Table

Data types for geoprocessing tool parameters

Script example

# BatchCheckGeometry.py
# Description: 
#   Loops through all the feature classes in a geodatabase, and generates 
#   a report of the problems encountered with feature geometry.
# Requirements: Python and the Python win32all extension
# Author: ESRI
# Data 1/1/2004

# Create the Geoprocessor
import arcgisscripting
gp = arcgisscripting.create()
inWorkspace = 'C:/ws/St_Lucia.mdb'
outTable = 'C:/ws/St_Lucia.mdb/checkGeometryResult'

# The workspace in which the feature classes will be checked
gp.workspace = inWorkspace

# A variable that will hold the list of all the feature classes (separated by semicolon)
inFeatureClasses = ""

# List all feature classes in feature datasets
fdss = gp.ListDatasets("","featuredataset")
fds = fdss.Next()
while fds:
    fcs = gp.ListFeatureClasses("*","",fds)
    fc = fcs.Next()
    while fc:
        if inFeatureClasses == "":
            inFeatureClasses = fds + "/" + fc
        else:
            inFeatureClasses = inFeatureClasses + ";" + fds + "/" + fc
        fc = fcs.Next()
    fds = fdss.Next()

# List all standalone feature classes
fcs = gp.ListFeatureClasses()
fc = fcs.Next()
while fc:
    if inFeatureClasses == "":
        inFeatureClasses = fc
    else:
        inFeatureClasses = inFeatureClasses + ";" + fc
    fc = fcs.Next()

# Put a try except look around the tool, in case an error occurs
try:
    print "Running the check geometry tool on %i feature classes" % len(inFeatureClasses.split(";"))
    gp.CheckGeometry(inFeatureClasses, outTable)
    print "%i problems were found, see %s" % (gp.GetCount(outTable), outTable)

except:
    # If an error occurred, print the messages returned by the tool
    print gp.GetMessages()
print "FINISHED"

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