topic Re: Problem with creating a Fishnet in ArcGIS Pro Questions

Problem with creating a Fishnet

Lucy — Sun, 13 Nov 2022 23:35:35 GMT

Hi,

I am having trouble with producing a fishnet for a sampling area that I want to produce sampling points/locations for.

I have used a polygon (in NZTM coordinates) as the extent (polygon of the boundary of the sampling area). I have also set the cell size width and height at 70m and this is the distance I want between sampling locations.

This seems to make a box to the side of the boundary and no fishnet? Screenshot attached.

Any help would be appreciated. Thanks.

Re: Problem with creating a Fishnet

DuncanHornby — Sun, 13 Nov 2022 23:51:49 GMT

Are you expect negative Y values?

Re: Problem with creating a Fishnet

Lucy — Sun, 13 Nov 2022 23:55:16 GMT

I am hoping for a grid to be generated within the boundary of the polygon

Re: Problem with creating a Fishnet

DanPatterson — Mon, 14 Nov 2022 00:01:44 GMT

could you specify the parameters you used?

Create Fishnet (Data Management)—ArcGIS Pro | Documentation

How Create Fishnet works—ArcGIS Pro | Documentation

Re: Problem with creating a Fishnet

Lucy — Mon, 14 Nov 2022 00:20:43 GMT

Template extent = BoundarylinePolygon (which then generates most on the inputs)

Cell Size width = 70

Cell Size Height = 70

Geometry Type = Polygon

Re: Problem with creating a Fishnet

DanPatterson — Mon, 14 Nov 2022 02:01:39 GMT

You have pending edits. Try finishing off the edit session and saving/discarding what you were working on first

Re: Problem with creating a Fishnet

DanLee — Mon, 14 Nov 2022 17:31:36 GMT

Hi Lucy,

You said "This seems to make a box to the side of the boundary and no fishnet?"

Could you measure the dimension of the box? Is it 70m x 70m or approximately 700m x 700m which seems the template extent? Looking at the trees in the background imagery, it's more like 70m x 70m. I am not sure why it only created one cell of the expected 10x10(?) fishnet. You can share your data, if possible.

What version of ArcGIS Pro are you using?

Re: Problem with creating a Fishnet

Lucy — Mon, 14 Nov 2022 23:51:45 GMT

Hi Dan,

I am using ArcGIS Pro 3.0.1. Attached are the boundary shape files if they are of use?

Re: Problem with creating a Fishnet

DanLee — Tue, 15 Nov 2022 04:46:48 GMT

Thanks for the data. It helped. Here is what I did:

1. Created a new project and added Port VilaBoundary.shp to the map.

2. Checked the layer's Properties and saw the projection and the Extent as shown below. Notice that all extent values are positive numbers. Which match the "N" (north) coordinates displayed at the bottom of the map (by the red arrow). I am not sure why the y coordinate at the bottom of your map shows "S".

3. I used "Browse..." option to browse to and select Port VilaBoundary.shp. The Template Extent values other necessary coordinate values were populated automatically. Specified 70 and 70 as the Cell Size Width and Height, and Polygon as the Geometry Type. The tool ran successfully and the fishnet was created as shown below.

Could you try the above and see if you get the same fishnet?

Re: Problem with creating a Fishnet

DanPatterson — Tue, 15 Nov 2022 09:14:18 GMT

Dan, what happens if you run your workflow but don't have saved/pending edits?

Re: Problem with creating a Fishnet

DanLee — Tue, 15 Nov 2022 15:42:52 GMT

Hi DanPatterson,

I made a copy of the shapefile to testEdit, added it to the map, added a field and calculated a value of the new field without saving the change. The tool warned about the pending edit but ran successfully because the tool doesn't use any feature information from the template feature class. I used 100 and 100 for cell width and height this time.

Re: Problem with creating a Fishnet

JcDuB — Sat, 18 Mar 2023 09:33:28 GMT

Hi Dan, I am having the exact same issue. The fishnet is a single cell the size of the boundary with no cells within, the attribute table only has 1 polygon. Could you explain your solution for me please? I don't understand what you mean by "added a field and calculated a value of the field" Do you mean added a field to the attribute table, and what did you calculate? Your assistance is much appreciated! Thanks.

Re: Problem with creating a Fishnet

DanLee — Mon, 20 Mar 2023 16:00:55 GMT

Hi JcDuB,

If you have read the entire conversation, you will see that I was responding to DanPatterson about having pending, unsaved edit while running Create Fishnet tool. What I did - "added a field and calculated a value of the field" - was just to create an unsaved edit. It has nothing to do with getting just 1 polygon.

It's more likely that you need to understand your data area/extent and use the right cell size or cell count. See the details in the entire conversation here. Hope that helps.