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I want to delete all the internal roads which exists in Block2. These roads don't have any attribute data. It is a single polygon. I need to extract only external roads. Block 2 should be made as Block 1. Block 1 is done by removing internal roads manually using "Cut polygon" tool.

I have so many block to work on. So, wanted to find an easier method

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  • First, thanks for your concern. I want to delete all the internal roads which exists in Block2. These roads don't have any attribute data. It is a single polygon. I need to extract only external roads. Block 2 should be made as Block 1. I have so many block to work on. So, wanted to find an easy method. Please help. – Anu Oct 25 '17 at 9:13
  • Are the external roads Always wider than the internal like in your screenshot? – BERA Oct 25 '17 at 9:23
  • No, some of the internal road's width match with external road's width but don't exceed. But, mostly external roads are wider. – Anu Oct 25 '17 at 9:29
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I would say it is very difficult since they are all the same polygon so you cant identify them by some attribute. If the external roads are wider you could try:

  1. Feature Vertices To Points (Advanced license required):

Creates a feature class containing points generated from specified vertices or locations of the input features

  1. Generate Near Table with the Points as input and with the Location parameter checked:

Calculates distances and other proximity information between features in one or more feature class or layer

  1. From the Near Table select rows/Point pairs with a specified small distance between them, for example all below a distance of just wider than the internal roads and then execute XY To Line:

Creates a new feature class containing geodetic line features constructed based on the values in a start x-coordinate field, start y-coordinate field, end x-coordinate field, and end y-coordinate field of a table.

You should now have created something like the red lines:

enter image description here

  1. Split Polygons With Lines on roads with the lines created:

This modelbuilder tool allows you to split polygons with lines in a geoprocessing operation

  1. Select and delete polygons below a certain area. If external roads get deleted you could try deleting small polygons and not to very elongated (ratio of shape area and shape lenght)
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  • I will come back once I get succeeded with your process. Thank you in advance.:) – Anu Oct 25 '17 at 9:38
  • I have got stuck at the 1st step. There are many unnecessary points/vertices generated on a single road. As these may create problem for the next step, I'm trying to remove them by using Simplify polygon tool. But, cannot remove all. I've been trying to add a screenshot in the comment section, but could not do so. Could you also suggest me how to add an image? – Anu Oct 25 '17 at 9:58
  • Then doing it like this might not be possible. – BERA Oct 25 '17 at 10:36
  • Generate Near Table with the Points as input and with the Location parameter checked: What would be the input for "Near features", -polygon? – Anu Oct 25 '17 at 11:09
  • The Points from feature vertices as Points as both in_features and near_features ("The same feature class or layer may be used as both input and near features.") – BERA Oct 25 '17 at 11:11

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