7 replies to this topic

[frax]

Hi,
Let's say I have a road element in Illustrator, and I want to redesign it. But now, this road is designed as a closed path, and the look of it is the fill of the path. In GIS-speak, it is a polygon.

Now, how can i (in Illy) get this back to a unclosed path (e.g. line feature) that I can style with the stroke... ?

[frax]

I can add that I can cut up the closed path to two nearly parallel paths easily - but that doesn't help me that much, since they are not parallel...

[david17tym]

I can add that I can cut up the closed path to two nearly parallel paths easily - but that doesn't help me that much, since they are not parallel...

Hi Frax,

ET GeoWizards for ArcMap allows you to create centrelines from polygons, see attached.

Dave

Attached Files

•  Image1.jpg   440.03K   46 downloads

[pfyfield]

I've done it with the blend tool (object-blend), although the results can be funky and I often just end up drawing the line.
You have to expand after using the tool to edit the centerline.

Do this on two roughly parallel lines, not a polygon.

[Hans van der Maarel]

FME has the CenterLineFinder transformer, if you want I can run it through that. Not sure how well it would work with these polygons by the way.

[I wonder how many people had placed bets on me coming up with an FME-related answer]

[Dennis McClendon]

In FreeHand you can Inset Path to get a smaller polygon whose sides would approximate the centerline. Presumably Illustrator has a similar function. Then you can split that very thin polygon and throw one side away. [I wonder how many people had placed bets on me coming up with an FreeHand-related answer.] But it's usually better to just redraw.

I often create rivers by drawing an approximate centerline and then expanding it into a polygon. I've learned to save the centerlines on a hidden layer in case I later need them for state or municipal boundaries, etc.

[frax]

Here are the responses from the Illy pros: http://www.adobeforu...ebx/.59b74d31/5

For ArcMap and FME answers - I don't want to go through the hassle to take these into GIS. Actually this is not a map, but a chart (not that it really matters).

Dennis - Illy doesn't have that functionality, as far as I know, one could do it using path finders, but that is too much of a hassle. I think blends was the best bet, but it doesn't work in my case - I am retracing...

[frax]

Actually what I'll do in this case is to digitize the lines in Grapher, then I can create new custom charts directly from it.