I have a large number of geometries, currently stored in Oracle, some of which contain arc segments.

I need to convert these geometries into LRS (Linear Referencing System) format so I would like to convert all the arcs to straight line segments.

I may have to write something in PL/SQL but, being a lazy sort, I was rather hoping someone had done this before.

Doesn't have to be in PL/SQL, I also have ArcGIS for Desktop, MapInfo, GeoMedia and FME if any of those would do it.

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    Just discovered ArcStroker in FME which looks like it may do the trick (once I've fixed the other problems with invalid geometries) – kenneedham Jun 20 '14 at 13:29
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    We use ArcStroker in FME to move CAD to GIS pure arcs to very small lines to preserve the arcs shape. – Mapperz Jun 20 '14 at 14:38

In FME, this is as simple as connecting your data to an ArcStroker transformer.

From the help page:

Converts arc features into lines replacing the feature geometry with a series of edges interpolated along the arc boundary. Ellipse features are converted into polygons by interpolating edges along the elliptical boundary.

If the input geometry is a path consisting of arcs and lines, or an area whose boundary is such a path, then any arcs in the path will be stroked, also using the Number of Interpolated Edges given.

enter image description here

There are a few parameters to allow you to determine how the arcs are stroked.

Prior to running it through the ArcStroker, you may want to filter your geometry using a GeometryFilter transformer. You can port the arcs separately, then join them back to your lines later on. Though, this may not be necessary.

  • Not sure why I never found ArcStroker before. I've definitely been through this on previous occasions, but then I always have a problem guessing what Safe have decided to call various transformers. Anyhow, it seems to work a treat of the geometries I've managed to patch up so far. – kenneedham Jun 23 '14 at 10:04

In ArcGIS for Desktop, you can use the tool Densify.

Adds vertices along line or polygon features. Also replaces curve segments (Bezier, circular arcs, and elliptical arcs) with line segments.

  • Exactly what I needed, thanks! I think this sufficiently answers the question, since the link elaborates on the content. – John Sep 30 '15 at 20:28

If you can copy your arcs into a shapefile and then from shapefile back to its original format then you should find that the true curves are now short segments.

I did this recently using the Copy Features tool of ArcGIS Desktop 10.0 to convert a true curve to a polyline of short segments in a file geodatabase.

The storage format is different but the principle remains the same.


First, use ogr2ogr and apply -segmentize option (recommended): http://www.gdal.org/ogr2ogr.html

Second, use Spatialite and apply ST_Segementize(): http://www.bostongis.com/PrinterFriendly.aspx?content_name=spatialite_tut01

Third, use PostGIS and apply ST_CurveToLine(): http://www.postgis.org/docs/ST_CurveToLine.html

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