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#1
aug_aug

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I am wondering how to "snap" or "smooth" two polygons together. I am working on a shapefile where the person who built it did not auto-complete polygons but drew over the existing shared edge between the two polygons.

Is there a way to quickly snap all edges within this shapefile together? It's a geologic map so there are lots of irregularly shaped polygons and it would be time consuming to re-create the entire layer. I'm using ArcView 9.3, but would consider using GRASS, QGIS, etc. if the capability is there.


Thanks!


Attached File  poly.jpg   42.94KB   70 downloads

#2
James Hines

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You also have another issue, the provided image is way too pixelated. You need to work on image quality first & foremost as far as quality is concerned because it looks too much like my basemap for the forest atlas from first year cartography.

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#3
Keith Map Service

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Try the Snap to Features function in ArcMap. It should be one of the editing tools I believe.
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#4
Crischan

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Using the snap function is handy when first digitizing, but not very helpful when you have to polygons with hundreds of nodes.
There are two tools I know of for this problem provided in the ArcGIS toolbox. If you have them all depends on your license.

* Integrate (Data Management tools)
* Clean (Coverage tools - needs a ArcInfo Workstation license)

Using coverage tools ususally yields better results, as coverages know topology.

Hope it helps.
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#5
frax

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For a quick and dirty way - you can try rasterizing the layer, and then vectorizing it back.

What happens if you don't display the boundaries, is there a lack of contrast between the polygons then? I am thinking that the sliver gaps/overlaps might not be so visible then.

If you are moving to illustrator later you can also play with the boundaries using live paint.

Hasdrubal - I think we are seeing a close-up, so the bg image (shaded relief?) might look ok/reasonable for the intended view.
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#6
jrat

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Depending on the licenses you have you can migrate the shapefile to a feature class in a feature dataset and define a topology. Tell the topology that you don't want any gaps. It will still be time consuming to fix all the topology errors but the software will find them for you. Run the integrate tool first before validating the topology. Integrate will add vertexes to ensure coincident geometry. sometimes even though the line is digitized over another if the vertexes do not line up the topology will identify them as an error.

#7
eli

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I'd solve this by using the Eliminate tool, although it's ArcInfo so I guess it won't work for you... if you can't find another way I could do it for you.

#8
aug_aug

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Sorry it took me so long to respond, out of town. Thanks for all the input, I'll report back if anything works.

I think the most limiting factor in solving this problem is going to be my Arcview licensing limits as there appear to be several tools to complete the task, and those tool names are what I was most interested in finding.

(Oh, and yes you are viewing lidar topography from a 1:60,000 scale map at ~1:20 super-zoomed-in, hence the 600 pt type below the polygon lines :wacko: . )

Thanks!

Michael

#9
aug_aug

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The integrate tool was easy and worked like a charm; my outlines are 1.2 pts thick, so slight gaps were covered up easily by a 15 foot xy tolerance.

I've realized that I'm not licensed for smooth line, smooth polygon, or create topology tools, which sucks. I'm going to see if ESRI help has a breakdown of all tools included with ArcView vs. ArcInfo somewhere.

Thanks again for your help!

:ph34r:

#10
Brian Moran

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Search for the "Zipper Task" on ESRI support. It's a tool you can download and use to "zip" coincident polygons together within a given tolerance. Works very well with poly feature classes with a topology layer for reference.




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