2

I've seen similar answers to this question on so many forums but nothing seems to work.

I have one large polygon (a country boundary) with another polygon layer that contains thousands of smaller polygons (separate sites, either independent polygons or sharing the same boundary) that fall inside, outside and across the large polygon. I want only the small polygons that fall outside the larger polygon even if it breaks the smaller polygon that fall across the larger polygon boundary. I have used the geoprocesing->clilp tool but I just get an error message (i.e. the ! symbol) and no new layer is created.

I'm using Arc 10.3.1. Is there any other tool I can use? (I've also tried intersection and select by location but clipping seems to be the one to use and it doesn't work!)

  • can you please clarify "even if it breaks the smaller polygon that fall across the larger polygon"? It would help if you could include some diagrams that illustrate the problem – Stephen Lead Sep 23 '16 at 6:53
  • Hi Stephen, sorry I can't upload an image. What I meant was some of the polygons from the layer I want to select from fall directly across the boundary of the layer I am using to select either inside or outside. I just want the polygons outside this boundary AND the proportion of overlapping polygons that also fall outside this boundary. D. – dash Sep 23 '16 at 11:59
1

use Erase tool, it will erase all polygon inside boundary and the border polygon it will clip them on the boundary.

you can find it at - toolbox\analysis tools\overlay\erase

  • Hi Florjan, thanks for the recommendation. I'm using that tool now (albeit with geowizards as I don't have access to that tool due to a basic Arc licence). It's taking firever though! The layer I'm trying to erase has about 24, 000 polygons, do you know if it should take this long? It's been running for almost 2 hours and seems to only be halfway through....there are no 'not responding' messages which is good – dash Sep 23 '16 at 11:31
  • i have never tested with all that number of polygons, but i think i has stocked, make firstly the selection by location and create a new shapefile within border polygons (to avoid big data), than apply erase tools it should take max 5 minutes. – Florjan Sep 23 '16 at 12:18
  • erase tools is what you require, it will extract outside polygons and the border polygon will be cut on the boundary (by deleting inside part and maintaining outside part) – Florjan Sep 23 '16 at 12:22
  • If you have problem with licenses for erase tool, you can use QGIS (Quantum GIS)it is an open source software. And you can find the same tools under "processing toolbox / Saga / Vector / Difference". – Florjan Sep 23 '16 at 12:35
  • 1
    This was the tool I needed Florjan, worked with ArcINFO locence instead of Geowizards – dash Sep 24 '16 at 7:55
1

The clip tool will not give you the results you want. If I understand you correctly, you need the polygons that fall outside the big polygon, but clip will select the polygons located inside the big polygon.

You need to use Select By Location to select the polygons that fall inside the big polygon or intersecting with the big polygons, as you can see below:

enter image description here

Then, use Switch selection to select the polygons that fall outside the big polygon.

enter image description here

Finally, save the selected polygon to a new shapefile.

  • Hi Ahmadhanb,Thanks for your response. I've just tried the select by location you recommend. I've used the 'are within the source layer feature' as the spatial selection method but as you can see it is not completely cutting the polygons at the country border boundary, so when I switch selection the polygons outside the country are going to contain the parts that are within the country boundary (see image). Will one of the spatial selection methods completely cut the polygons at the grey boundary? Many thanks D. – dash Sep 23 '16 at 9:21
  • So sorry, I can't upload my image for some reason! – dash Sep 23 '16 at 9:28
  • In the image above, I used "have their centroid in the source layer feature" which is the last option in the drop-down menu in the Select by Location, which means if the center of the polygon is located inside the big polygon, it will be selected. Then I used Switch Selection. – ahmadhanb Sep 23 '16 at 9:32
  • Hi Ahmadhanb, I can't zoom in on your image. Does this option clip the boundary of the polygons at the border of the larger polygon? I just want a clean cut of anything inside versus anything outside. Many thanks again. D. – dash Sep 23 '16 at 11:34
  • No it is just selection. It will not clip anything. You will select the polygons fall outside the big polygon. – ahmadhanb Sep 23 '16 at 11:45

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.