每種軟件都有自己的數據規範，ArcGIS也不例外，當數據不滿足ArcGIS的規範時，就會遇到各種無響應和崩潰。
有關數據幾何錯誤總是問題相對較多的部分。其中，shapefile作爲一種開放的格式，除了ArcGIS程序可以讀寫，也可以按照數據規範在非ArcGIS環境中生產。後者生產的數據通常包含這樣那樣的問題，這些問題都是幾何錯誤的範疇。
幫助原文說的精闢：
The shapefile is an open format to which many software
packages write. Unfortunately, some of these software packages—sometimes due to bugs, sometimes due to lack of knowledge—do not follow the documented specification of the shapefile format.
簡單羅列下ArcGIS中不能允許的幾何錯誤類型：
短線段/Short segment：
Some segments are shorter than allowed by the system units of the spatial reference associated with the geometry.
空幾何/Null geometry
The feature has no geometry or nothing in the SHAPE field.
不正確的環順序/Incorrect ring ordering
The polygon is topologically simple, but its rings may not be oriented correctly (outer rings—clockwise, inner rings—counterclockwise).
不正確的線段方向/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.
自相交/Self intersections
A polygon must not intersect itself.
非封閉環/Unclosed rings
The last segment in a ring must have its "to" point incident on the "from" point of the first segment.
空部分/Empty parts
The geometry has multiple parts and one of them is empty (has no geometry).
重複折點/Duplicate vertex
The geometry has two or more vertices with identical coordinates.
屬性不匹配/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.
不連續部分/Discontinuous parts
One of the geometry's part is made up of disconnected or discontinuous parts.
空Z值/Empty Z values
The geometry has one or more vertex with empty Z value (NaN, for example).
以上的錯誤，可以用使用工具 Check Geometry 進行檢查，工具會生成有關幾何錯誤的報表。使用 Repaired Geometry 工具進行修復。
文章作者：kikita的月亮井