Selecting data points from a plot

I have a TON of longitude and latitude data points that I used to create this figure of some lakes I am helping research. I would like to isolate the points shown while keeping only the outline of the lake. I want to show flowrates and things from each point, which will make it very messy if I include every single coordinate. I also want the user to be able to tell where in the channel we are looking, hence the need for the outline. Is there an easy way I can do this? I know I could just manually click every point and export them to my workspace but that seems awful.

[KSSV]

How you have the data points? Are they scattered points? Attach your data.

[Star Strider]

I thought about using boundary with a shrink factor of 1 (the highest possible value), however when I simulated it, that didn’t give the the result I was hoping for.

One option would be to use islocalmax and islocalmin on appropriate parts of the lake shore (I assume the blue dots define the lake and the white areas are land), although that might require manually selecting the (x,y) regions first for at least some of them.

I’m not posting this as an Answer because it isn’t one. However if an extension of it (with your data to test it with) helps to solve your problem, I’ll post the updated version as an Answer.

Answer 1

[KSSV]

A rough idea would be to use boundary.