Skip To Content

Check Geometry

Summary

Generates a report of the geometry problems in a feature class.

Valid input formats are shapefile and feature classes stored in a file geodatabase.

For additional information on geometry problems, its impact on the software, and potential sources, see Checking and repairing geometries.

Usage

  • The Output Table will have a record for each geometry problem discovered. If no problems are found, the table will be empty.

  • 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 codes:

    • 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 segment i should be incident on the from point of segment i+1.
    • Self intersections—A polygon must not intersect itself.
    • 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).
    • Duplicate vertex—The geometry has two or more vertices with identical coordinates.
    • Mismatched attributes—The z- or m-coordinate of a line segment's endpoint does not match the z- or m-coordinate of the coincident endpoint on the next segment.
    • Discontinuous parts—One of the geometry's parts is made up of disconnected or discontinuous parts.
    • Empty Z values—The geometry has one or more vertices with an empty z-value (NaN, for example).
    • Bad envelope—The envelope does not match the coordinate extent of the geometry.
    • Bad dataset extent—The extent property of the dataset does not contain all of the features in the dataset. For this problem the FEATURE_ID will be -1.
  • The problem identified by this tool can be addressed in the following ways:

    • Manually edit and fix the feature with the geometry problems. Some of the problems cannot be fixed through editing.
    • Use the Repair Geometry tool.
  • The Output Table contents, including the PROBLEM codes are written in English.

  • For point features, only the null geometry problem is possible.

  • To facilitate the review of the features that are reported to have geometry problems, you can join the Input Features to the Output Table using the Add Join tool, along with the input's OBJECTID or FID field and the output table's FEATURE_ID field.

  • The Esri validation method ensures geometry is topologically legal using the ESRI Simplify method.

  • The OGC validation method ensures geometry complies with the OGC specification as defined in OpenGIS Implementation Standard for Geographic information – simple feature access – Part 1: common architecture.

  • After a feature's geometry is repaired using the OGC option, any subsequent edit or modification may cause the geometry to no longer comply with the OGC specification. After feature modification, run the Check Geometry tool to check for new geometry issues. If necessary, rerun the Repair Geometry tool.

  • OGC simplify does support nonlinear segments such as Bézier curves, circular arcs, and elliptic arcs. These types of segments will have to be densified using the Densify tool on the input dataset before running Check Geometry. To avoid irreversibly changing nonlinear segments when running the Densify tool, make a copy of the data first. To determine if your data has nonlinear segments, use the Add Geometry Attributes tool.

Syntax

CheckGeometry_management (in_features, out_table, {validation_method})
ParameterExplanationData Type
in_features
[in_feature,...]

One or more feature classes or feature layers to check for geometry problems.

Feature Layer
out_table

The report (as a table) of the problems discovered.

Table
validation_method
(Optional)

Specifies which geometry validation method will be used to identify geometry problems.

  • ESRI Esri geometry validation method will be used. This is the default.
  • OGC Open Geospatial Consortium (OGC) geometry validation method will be used.
String

Code sample

CheckGeometry example 1 (Python window)

The following Python window script demonstrates how to use the CheckGeometry function in immediate mode.

import arcpy
arcpy.env.workspace = "c:/data/data.gdb"
arcpy.CheckGeometry_management(["contours", "roads", "vegetation"], "CheckGeom_Result")
CheckGeometry example 2 (stand-alone script)

The following stand-alone script uses the CheckGeometry function by looping through all the feature classes in a geodatabase.

# BatchCheckGeometry.py
# Description: 
#   Loops through all the feature classes in a geodatabase, and generates 
#   a report of the problems encountered with feature geometry.

# Import modules
import arcpy
import os

# The geodatabase in which the feature classes will be checked
arcpy.env.workspace = "C:\\data\\St_Lucia.gdb"
out_table = "checkGeometryResult"
 
# A variable that will hold the list of all the feature classes 
# inside the geodatabase
fc_list = []

# Identify all feature classes in the geodatabase
for path, dirnames, fcs in arcpy.da.Walk(arcpy.env.workspace, 
                                         datatype='FeatureClass'):
    for fc in fcs:
        fc_list.append(os.path.join(path, fc))
        
print("Running the check geometry tool on {} feature classes".format(
    len(fc_list)))
arcpy.CheckGeometry_management(fc_list, out_table)

print("{} geometry problems found, see {} for details.".format(
    arcpy.GetCount_management(out_table)[0], out_table))

Licensing information

  • ArcGIS Desktop Basic: Yes
  • ArcGIS Desktop Standard: Yes
  • ArcGIS Desktop Advanced: Yes

Related topics