topic Re: GIS Vector Data blank space in ArcGIS Spatial Analyst Questions

GIS Vector Data blank space

DanielleLoring — Tue, 24 Nov 2015 21:56:03 GMT

Hi everyone. I am in an environmental modeling class as a graduate student. I am currently working on a lab and need some help figuring out how to do something. We have a vector file of different land use types but as you can see there is white space within that we need to fill in and add another land use type. I'm not sure what the easiest way to fill this space in is. I only need the long section and a few other small sections, not every white space. Any help or advice is greatly appreciated. Thank you!

Re: GIS Vector Data blank space

JasonBuck — Tue, 24 Nov 2015 22:01:56 GMT

Danielle,

Try using the Symmetrical Difference tool. You could create a dummy polygon dataset that would cover the extent of the dataset with the whitespaces. Symmetrical Difference will create polygons where there is a difference between the two datasets. You can then copy the resulting data back into the dataset with the whitespaces.

Jason Buck

Re: GIS Vector Data blank space

DarrenWiens2 — Tue, 24 Nov 2015 22:03:56 GMT

1.) Draw a big, rough polygon in a new feature class, covering the space you want to add. It can overlap with the existing polygons.

2.) Erase the existing polygons from the new polygon.

3.) Append the new feature class (your big polygon with the existing polygons erased) to the existing polygons

Re: GIS Vector Data blank space

DanielleLoring — Tue, 24 Nov 2015 22:04:19 GMT

If we only have the one dataset with the missing information will it still work? Our professor only gave us the dataset with missing data but still expects us to be able to figure out how to fix it.

Thank you so much for you help

Re: GIS Vector Data blank space

DarrenWiens2 — Tue, 24 Nov 2015 22:16:47 GMT

Ah, good to know about Symmetrical Difference. Jason Buck's suggestion will save you the Append step.

Re: GIS Vector Data blank space

DanielleLoring — Tue, 24 Nov 2015 22:20:15 GMT

When I'm drawing the polygon, should I be drawing it over the existing polygon dataset or no? I drew a polygon over the area I wanted it to cover, converted it to a feature class and tried using the symm. diff. tool but it turned everything under the polygon to a new polygon. I just want the blanks changed. Maybe I'm missing something but this has got me completely stumped and I'm usually pretty efficient with GIS

Re: GIS Vector Data blank space

DarrenWiens2 — Tue, 24 Nov 2015 22:27:37 GMT

Yes, your new polygon can overlap the existing polygons, but it must be in a new feature class (not the same feature class as your existing polygons). When you run Erase (or Symmetrical Difference), the area in your new feature class overlapped by your existing polygons should disappear - or at least, that's the idea.

Re: GIS Vector Data blank space

DanielleLoring — Tue, 24 Nov 2015 22:52:43 GMT

THANK YOU! It finally worked. You guys were both a huge help!