topic Re: Subpopulations of fish in ArcMap Questions

Subpopulations of fish

GysaLangelet — Tue, 28 Jan 2025 18:40:35 GMT

Hello everyone

I am trying to map ‘fish populations’ on Arcmap. I have a dataset with points in the watercourses where the specific fish occurs and I have an hydrogeographic atlas. Now I want to highlight the rivers starting from the point where the fish was caught all the way up & down to 3km from that point (when the waterstream splits it should follow both parts). Like this I want to create subpopulations, so the highlights will often overlap when there are points nearby eachother.
i tried following steps but this did not give the result that I wanted:

1. create routes (linear referencing toolbox)

2 locate feature among routes (lrt)

3 add ‘from (meas -3000) and to (meas + 3000)

4 make route event layer

Re: Subpopulations of fish

ZachBodenner — Tue, 28 Jan 2025 19:40:28 GMT

Are you just looking to visualize the 6km stretches of rivers? Are you able to create new separate river layers and still achieve your goals?

Re: Subpopulations of fish

GysaLangelet — Tue, 28 Jan 2025 19:44:28 GMT

Hello,

Yes it’s just to visualize. It can be seperate layers.

Re: Subpopulations of fish

ZachBodenner — Tue, 28 Jan 2025 20:04:49 GMT

Well, this is a bit of a roundabout process, so I hope you don't need to do it too many times, but it is at least an option:

1. Duplicate your rivers layer to ensure a "master" copy stays intact

2. Use the Split tool and choose "by feature". Use the fish point as the input and the copied river layer as the target

3. Use the Divide tool and specify the distance along the line to split the feature. Do that for both of the new segments generated in step 2

Then you're left with a few new segments: Two on each side of the point you can either export to a new feature class or adjust the attributes to visualize differently than your underlying master layer.

Again, a tad roundabout, but lacking a single tool function to bundle each of these (I recommend submitting an idea if no other community members know of a way to do that), it could work for you.

Re: Subpopulations of fish

DuncanHornby — Sun, 16 Feb 2025 18:14:31 GMT

If you have access to ArcPro then have a look at RivEX, it has many tools for processing sites along rivers. You can very easily create 3km u/s and d/s reach polylines by using one of the reach generation tools. The RivEX manual has a section of worked examples to inspire users with the wide range of river related processing that can be done.