Posts Tagged ‘repair’

Problems Dissolving in ArcMap, Try Repairing Geometry First

Tuesday, July 14th, 2009

[Editor's note: I was having trouble last week dissolving a shapefile based on a common attribute. I kept getting the following error: "Invalid Topology [INCOMPLETE_VOID_POLY]“. Not entirely helpful! A little Google searching turned up the following tip from ESRI.]

Republished from ESRI.

Problem:  Some Overlay Tools, such as Intersect, return unexpected results or fail


Results do not look correct or operations fail with strange errors such as:

“Invalid Topology [INCOMPLETE_VOID_POLY]“.

If this type of error has occurred, it is most likely to occur when using one of the following:
Clip, Erase, Identity, Intersect, Symmetrical Difference, Union, Update, Split Featureclass to Coverage, Dissolve, Feature to Line, Feature To Polygon, Integrate, or ValidateTopology.


It is possible that tool outputs may be strange or incorrect because one or more features in the input feature class have geometry problems. Some examples of geometry problems are:

· short segments
· null geometry
· incorrect ring ordering
· incorrect segment orientation
· unclosed rings
· self-intersections or empty parts

Solution or Workaround

If such errors occur or the output looks incorrect, the first step in assessing the situation is to run the ArcToolbox tool Data Management Tools > Features > Check Geometry. -show me

[O-Image] Check Geometry

This tool provides a list of the invalid features in the feature class and a short description of the problem. Features with problems can be fixed in one of two ways:

  • Editing the feature class with the geometry problem, and fixing each individual problem identified. Some of these problems, like non-simple geometry, can be fixed by double-clicking the feature in the editor and saving the edits.
  • Running the ArcToolBox tool Data Management Tools > Features > Repair Geometry on the feature class containing the problem features. -show me

Getting Stuck (NY Times)

Tuesday, May 20th, 2008

Editor’s note: I like how the “worst 10″ table shows all the different map variables in a single matrix where they can be compared numerically. The map shows “all” the sundry elevators in New York City as graduated circles where they can be compared visually. The circles are graduated in size for any of three variables. The mapped variable is chosen with a dropDown menu easily found at the top of the display. There is not an overwhelming number of variables, but those that are listed are fully integrated and cross referenced within the display by using rollOvers on each circle. The DNA-sequence-style time series below the map shows breakdowns by day for 2 elevators and provides a finer resolution picture than the year-sum map. It would be cool if the table and the map could trigger each other (on mouseOver the Times Square station on the map, that row in the table highlights, and visa versa).

May 19, 2008 by Matthew Bloch, Shan Carter and Ford Fessenden/The New York Times

A New York City Transit program to install elevators and escalators in the city’s subway system has been plagued with problems. The machines often break down or are closed for repairs and maintenance and many people have been stuck in elevators. Last year, there were 286 incidents, known as entrapments, in which passengers were stuck in elevators, up from 177 in 2006.

Screenshot below. See and interact with the original Flash graphic here.

ny city elevator outages