Check Geometry (Data Management)

Summary

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

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

Usage

• Valid input formats are shapefiles, and feature classes stored in a file or enterprise geodatabase. For feature classes stored in an enterprise geodatabase, the following spatial types are supported:

  • Microsoft SQL Server Geometry and Geography
  • PostgreSQL PostGIS Geometry and Geography
  • Oracle SDO Geometry

• 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 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 that geometry is topologically legal using the Esri Simplify method. Only the Esri validation is available for data stored in an enterprise geodatabase.

• The Open Geospatial Consortium (OGC) validation method ensures that 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.

• The OGC simplify method does not 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 whether your data has nonlinear segments, use the Add Geometry Attributes tool.

• The problems 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. Some problems associated with data stored in an enterprise database may not be repairable with ArcGIS tools.

• 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 sequential 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 composed 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.

  For data stored in enterprise geodatabases, the PROBLEM field will contain one of the following codes:

  • NEEDS_REORDERING—The shape is OK except that it needs to be reordered and/or have duplicate points removed.
  • SE_INVALID_ENTITY_TYPE—Invalid entity type.
  • SE_SHAPE_INTEGRITY_ERROR—Shape integrity error.
  • SE_INVALID_SHAPE_OBJECT—The given shape object handle is invalid.
  • SE_COORD_OUT_OF_BOUNDS—The specified coordinate exceeds the valid coordinate range.
  • SE_POLY_SHELLS_OVERLAP—Two donuts or two outer shells overlap.
  • SE_TOO_FEW_POINTS—The number of points is less than required for the feature.
  • SE_INVALID_PART_SEPARATOR—Part separator in the wrong position.
  • SE_INVALID_POLYGON_CLOSURE—Polygon does not close properly.
  • SE_INVALID_OUTER_SHELL—A polygon outer shell does not completely enclose all donuts for the part.
  • SE_ZERO_AREA_POLYGON—Polygon shell has no area.
  • SE_POLYGON_HAS_VERTICAL_LINE—Polygon shell contains a vertical line.
  • SE_OUTER_SHELLS_OVERLAP—Multipart area has overlapping parts.
  • SE_SELF_INTERSECTING—Linestring or poly boundary is self-intersecting.

Syntax

arcpy.management.CheckGeometry(in_features, out_table, {validation_method})

Parameter	Explanation	Data 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 the geometry validation method that 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 in a file geodatabase.

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 file 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))

Environments

Extent, Scratch Workspace, Current Workspace, Output CONFIG Keyword

Licensing information

• Basic: Yes
• Standard: Yes
• Advanced: Yes