# How to rename points by clockwise direction or change starting point in polygon features?

I have a polygon feature class. I convert it to a point. Name of field (for example !Number!) in a point feature converted from polygon "A2"(The first point should be in the upper left corner (relative to north) of the polygon.) must match the direction of points in a clockwise. I know "AutoIncrement ()" at using Field Calculator, to change the numerical name of points by OBJECTID, but the point ID identifier sometimes do not match with the clockwise direction. Only one method that I know is to copy the contents of a table in Excel and renumber as I need. Then insert into ArcGIS the modified table in Excel and "display XY data"->"Data"->"Export data to point features". But maybe someone knows how to do it easier?

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Do you need to create new polygons so the vertex order starts in the Upper-Left or do you want a list of vertices, for each polygon, in the corrected order? – klewis Nov 22 '13 at 0:28
Both variants are good. I know how to fix the order of the vertices using Excel, but it is slow and not always convenient method. As a result, I need to make a list of vertices (including coordinates) for each polygon in the correct order. And the correct order of the vertices must be displayed on the map. I need the fastest possible way. – Jannik Nov 26 '13 at 0:08
Perhaps it might look like , 1 Use the repair tool geometry and vertex IDs goes clockwise direction . 2 converted polygons to points. 3 in attribute table using python autoIncrement () "expression. cal" 4 From upper left points are numbered with pStart = 1. 5 The rest of the points are numbered with pStart => next number of the last numbered point in paragraph 4 . 6 As a result, the point of going clockwise direction points are numbered as I need to . But they have the wrong ID order. Maybe it's not so important. Do you think there is another way more faster? – Jannik Nov 26 '13 at 5:32

Use the Repair Geometry tool - the polygon will be reset as clockwise direction.

The Check Geometry documentation says:

Incorrect ring ordering—The polygon is topologically simple, but its rings may not be oriented correctly (outer rings—clockwise, inner rings—counterclockwise).

While the Repair Geometry documentation does not mention clockwise/counterclockwise but says:

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

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The first point should be in the upper left corner (relative to north) of the polygon. – Jannik Nov 21 '13 at 9:02
There is no topological requirement in GIS software that specifies where the first point should be. What is the rationale for such a need? – blah238 Nov 21 '13 at 9:04
Conditions of numbering for issue of cadastral parcels. – Jannik Nov 21 '13 at 9:31

The Production Mapping extension includes a Set Origin Vertex tool that may suit your purposes:

A polygon is a collection of rings. Rings contain collections of points, or vertices, which describe a closed path. The first vertex, number 0, in the outermost ring of a polygon is the origin vertex. Vertices are oriented in a clockwise direction from the origin vertex. The origin vertex is the from-point (and to-point) of the ring that encloses a polygon.

The Set Origin Vertex tool allows you to change the origin vertex of a polygon feature. The following workflows may require you to use this tool:

• Grid and graticules layers—Set an origin location for an area of interest.
• Suppress outline geometry effect—Control where line suppression starts.
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Ow it`s look like very simple but we don`t have "Production Mapping extension". Maybe you know another way? – Jannik Nov 22 '13 at 8:43