# Extending buffer zone

I am working in ArcMap 10.2 (and Modelbuilder) and I would like to solve the following problem:

I have Buffer A (single part) and Buffer B (multipart). I would like to extend Buffer A with Buffer B where there is an overlap between Buffer A and Buffer B or where both lines are within halve the distance of Buffer B. Though the extention used should be halve of the buffer distance used to create Buffer B (there are many different Buffer distance values used). So assume Buffer B1 has a buffer distance of 5m I would like Buffer A to be extended with 2.5m where there is an overlap between Buffer A and Buffer B1. If Buffer B2 has a buffer distance of 8m Buffer A should be extended with 4m where Buffer A and Buffer B2 overlaps. When Buffer B1 or any other part of Buffer B lies within halve the distance of the buffer distance used from Buffer A it should take that part with Buffer A as well.

The result (when dissolving the boundaries of the Buffer) would look something like the following:

Suggesting a workflow:

Starting point is after the creation of Buffer B.

1. For Buffer A use the multiple ring buffer creating two buffers. The original one and another one which is 1.5 times the distance. E.g 12 meters and 8 meters.
2. For buffer B open a new field (float, named "expand"), and feed it with [BUFF_Distance]/2
3. Use intersect to create an intersection between both Buffers (multi-buffer A and buffer B). That will give you the overlapping areas as polygons.
4. Create Buffer around the results using the "expand" field as distance.
5. Merge the extended buffer created at step 4 with inner A Buffer. That is to pre-select it and export to a new layer/tmp. layer.
6. Dissolve the result.

First image show an example for input data with buffer A (multiple) and B. Dimensions are 12, 8 for A, and 3 for B (all in meters). Selected is the 8 meters Buffer of the A multiple buffer.

Second image show the result - which is Buffer A - 8 meters and the expand buffer, after being merged and dissolved (steps 5 - 6)

• Hi dof1985, thanks for answering my question. I did not try it yet but I will 2morrow, I was only wondering why you choose a distance of 1.5 times the original distance in step A? Apr 8, 2015 at 19:15
• @Danielle - This is meant to serve the second goal of your question, i.e. to also expand the buffer of those B buffer Zones that are half the distance of Buffer A from the buffer itself. Thus creating the original buffer, gives you overlay, and the left 0.5 (from 1.5) answer the second condition. Apr 8, 2015 at 20:02
• Ah okay, now I understand. I did not write it well though I meant halve the distance of buffer B, sorry for the misunderstanding Apr 9, 2015 at 4:34
• @Danielle - I guess the tecnique is the same, just change the multi-buffer accordingly. Apr 9, 2015 at 7:36