topic Re: select features within boundary in Geoprocessing Questions

select features within boundary

OzKhan — Mon, 11 Apr 2016 16:43:00 GMT

Hi all,

I am using basic version of ArcMap. I would like to extract only the portion of purple polygon inside the line boundary. How can I do that?

(The purple is ROW and the the blue line is the proposed road layout. I am trying to plot the impacted ROW.)

Re: select features within boundary

DarrenWiens2 — Mon, 11 Apr 2016 16:44:53 GMT

You need to convert the line to a polygon (perhaps using Feature To Polygon, I use ET GeoWizards) and then Clip or Intersect.

edit: is your ROW a polyline or polygon feature class? If polygon, just Clip or Intersect.

Re: select features within boundary

NeilAyres — Mon, 11 Apr 2016 16:48:20 GMT

In editing, doesn't clip feature do what you want?

Re: select features within boundary

OzKhan — Mon, 11 Apr 2016 17:10:36 GMT

ROW is polygon. While the road layer is polyline. Its not doing what I want...

Re: select features within boundary

OzKhan — Mon, 11 Apr 2016 17:12:24 GMT

I would like to select what is inside and not what is outside the boundary

Re: select features within boundary

DarrenWiens2 — Mon, 11 Apr 2016 17:23:07 GMT

What is it doing?

Re: select features within boundary

OzKhan — Mon, 11 Apr 2016 17:38:40 GMT

Well actually I tried to convert the polyline to polygon using GeoWizards like you advised. However, it only converts maybe those lines that do not have gaps. How can I close all the line gaps first to convert to polygon?

(it only converted the inscribed circle to polygon)

Re: select features within boundary

DarrenWiens2 — Mon, 11 Apr 2016 17:44:33 GMT

Yes, you do need closed polylines. If ET GeoWizards Polylines to Polygons tool doesn't work, go to the Build Polygons tool in the Polygon toolset and follow those instructions.

Re: select features within boundary

OzKhan — Mon, 11 Apr 2016 17:49:24 GMT

Have a lot of lines...

Re: select features within boundary

DarrenWiens2 — Mon, 11 Apr 2016 17:57:27 GMT

Hmmm the dialog gives you an option (register the product). You could convert polylines to polygons using Python geometry objects, but I'm somewhat pressed for time at the moment.

Re: select features within boundary

DarrenWiens2 — Sat, 11 Dec 2021 22:14:51 GMT

Here is at least most of what you'd need to convert polyline to polygon via Python:

>>> in_lines = "open_lines" # input lines
... sr = arcpy.Describe(in_lines).spatialReference # CRS
... out_polys = [] # output list
... with arcpy.da.SearchCursor(in_lines,'SHAPE@',spatial_reference=sr) as cursor: # loop through lines
...     for row in cursor: # for each record
...         new_polyline_array = arcpy.Array()
...         for part in row[0]: # for each geometry part, if multipart
...             new_polyline_part_array = arcpy.Array()
...             for pnt in part: # for each vertex
...                 new_polyline_part_array.add(pnt) # add the vertex to the array
...             if not part[0].equals(pnt): # check if part is closed
...                 new_polyline_part_array.add(part[0]) # if not, close it
...             new_polyline_array.add(new_polyline_part_array) # add the parts to the output list
...         out_polys.append(arcpy.Polygon(new_polyline_array,sr)) # convert the output list to polygon objects
... arcpy.CopyFeatures_management(out_polys,r'in_memory\out_polys') # write to disk

Re: select features within boundary

OzKhan — Mon, 11 Apr 2016 18:46:53 GMT

I am not much into programming. However, I tried a different approach and it worked.

1. I used DISSOLVE to convert all the polylines back to polylines. This takes care of all the gaps.

2. Used the ET GioWizards tool to convert the newly created polylines to polygon.

3. Used clipping features to selet only those that are impacting.

Thanks for all the help and suggestions...

Re: select features within boundary

DanPatterson_Retired — Mon, 11 Apr 2016 19:07:07 GMT

moved to Geoprocessing

Re: select features within boundary

WesMiller — Mon, 11 Apr 2016 19:25:12 GMT

Create a new polygon feature class and use your trace tool to create the polygons then use the clip or intersect tools.

Creating a new shapefile—Help | ArcGIS for Desktop