topic Re: Lines to polygons in Data Management Questions

Lines to polygons

MichalBrach — Wed, 26 Sep 2012 12:57:23 GMT

I'd like to generate polygons which represent tree crown.
I have many lines and I want to convert it to separate polygons - I mean one closed line to one polygon.
[ATTACH=CONFIG]17997[/ATTACH]
Unfortunately the tool "Feature to polygon" creates polygons in every closed area and generate many polygons I do not need at all.
On the picture below I selected some of this polygons I do not need.
[ATTACH=CONFIG]17998[/ATTACH]
Is it possible to create polygons from lines without intersections??
I attached line shapefile.

Re: Lines to polygons

michaelcollins1 — Wed, 26 Sep 2012 13:13:16 GMT

I don't have access to that tool (I only have ArcGIS basic). Try ET Geowizards Polyline to Polygon tool, it does what you need.

http://www.ian-ko.com/

Re: Lines to polygons

Anonymous User — Wed, 26 Sep 2012 17:20:27 GMT

Original User: mif4i

I don't have access to that tool (I only have ArcGIS basic). Try ET Geowizards Polyline to Polygon tool, it does what you need.

http://www.ian-ko.com/

But this is quite expensive extension. I'm not sure I can do it by demo version of ET Geowizard 😞

Re: Lines to polygons

HardolphWasteneys — Fri, 05 Oct 2012 05:21:32 GMT

Michal,

Interesting problem; as you say there is no automatic way of creating ONLY a single polygon from each polyline outline when they overlap others. Ideally, the polygon creation would go record by record or you could have a tool to sort the set into non-overlapping files.

For this I just manually split the set up into 4 non-overlapping shapefiles, which was kind of amusing, and ran each to create polygons in a common target polygon shapefile. Worked fine and I symbolized them by area as shown in the figure. Use the "Copy Features" tool to create the new files and maintain the attributes. I just did a select, right-click copy, r-c delete, r-c paste to a Target shapefile and then copied and merged the polylines in a scratch shapefile (see http://forums.arcgis.com/threads/6786-polyline-to-polygon)

Hardolph

[ATTACH=CONFIG]18217[/ATTACH]

p.s. in Arc10.1 you might be able to use modelbuilder and the iterate over records function http://resources.arcgis.com/en/help/main/10.1/0040/00400000000n000000.htm

Re: Lines to polygons

Anonymous User — Fri, 05 Oct 2012 06:55:07 GMT

Original User: mif4i

For this I just manually split the set up into 4 non-overlapping shapefiles, which was kind of amusing, and ran each to create polygons in a common target polygon shapefile.

Hardolph,

The result is perfect. The question is how you split the polylines into 4 non-overlapping shapefiles? This is the most important because using Merge function is clear for me.
By the way as Mcollinsamec mentioned the free function ET Geowizards Polyline to Polygon do it at once.

Re: Lines to polygons

HardolphWasteneys — Sat, 06 Oct 2012 05:16:32 GMT

Michal,

I split the polygons into 4 shapefiles manually: I simply selected first one non-overlapping set covering as much of the original 'lines" file as possible right click copied the selection, deleted them and pasted them into another shapefile using create features and Target: the second shapefile, then repeat the process with the remaining outlines and a new shapefile until the remainder was a non-overlapping set. I then copied and pasted and merged each set in a scratch file and ran the "Autocomplete Polygons" process on each merged set with the Target being a Polygon shapefile.. Actually, the other polyline shapefiles were not strictly necessary except to make it easy to see that I had 4 non-overlapping sets or if one used the Copy Features tool to preserve attributes.

I am not familiar with the ET geowizards Polyline to Polygon tool, but I expect it would works the same as "Autocomplete Polygons" and the new functions in ArcGIS 10 that produce polygons from all the intersecting outlined areas rather than one per record.

Hardolph