ArcGIS的检查与修复工具

昨天检查一区属性发现一区图层的面积属性shape_area竟然出现了负值，想必是数据转换的时候出现了问题。今天在论坛求证了一下，感谢各位的解答。

ArcGIS默认顺时针图形为正，手工画polygon的时候不管怎么画结果都是顺时针的。所以一般负值的出现是转换过程出现问题，polygon是由ring组成的，ring则是有更小的segement（line,circularArc,ellipticalArc,beziercurve）构成，所具有方向性。

解决方法是用ArcTool中的check geometry和 repair geometry工具，上述的检查结果是Incorrect ring ordering。repair后会自动修复错误，已解决。

此外，repair工具只能修复以下五种错误：

Null geometry―The feature will be deleted from the feature class.

Short segment―The geometry's short segment will be deleted.

Incorrect ring ordering―The geometry will be updated to have correct ring ordering.

Incorrect segment orientation―The geometry will be updated to have correct segment orientation.

Self intersections―The geometry's segments that intersect will be split at their intersection.

Unclosed rings―The unclosed rings will be closed.

Empty parts―The parts that are null or empty will be deleted.

更多的错误修复参照帮助中的 How to salvage a corrupt shapefile

在用clip命令时出现错误：'Invalid Topology [INCOMPLETE_VOID_POLY]

Description

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.

Cause

It is possible that tool outputs may be strange or incorrect because one or more features in your input feature class have geometry problems. 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 you are seeing such errors or your output looks incorrect, the first step in assessing the situation is to run the ArcToolbox tool Data Management Tools > Features > Check Geometry. -show me-

This tool will give you 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.

1、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.

2、Running the ArcToolBox tool Data Management Tools > Features > Repair Geometry on the feature class containing the problem features.