Coastal Vulnerability: shore point distribution issue

Hi all,

Currently I am using the coastal vulnerability model (InVEST 3.13.0) to conduct my research project. I have successfully run the model; however, I have noticed that the shore points established by the model are unevenly distributed. Despite setting the model resolution to 500m, I encountered the situation where several kilometers of coastlines lack any coastal points. Also, certain points are not distributed along the coastline but rather along the AOI boundary that borders the surrounding land.

I guess the issue might be related to the AOI and landmass data layers? I downloaded these data online, but found they were not up to date and did not fully cover the study area. So I slightly modified the boundaries to make them more accurate. I’m not sure if I did anything wrong while editing the data.

The issue looks like this:

Here is the logfile:
InVEST-natcap.invest.coastal_vulnerability-log-2023-06-23–20_12_24.txt (8.1 KB)

Thank you!

Hi @NicoleLin , thanks for posting and including a picture of the problem. I think you’re correct that the issue is likely related to the AOI and landmass layers. The easiest thing to do might be share those datasets and I can take a closer look.

It’s a bit hard to diagnose from the picture. Is the purple the AOI or the landmass? If the landmass has multiple disjoint features (e.g. islands) they will all get at least one shore point, even if their circumference is less than the model resolution distance. I’m not sure if that’s what is going on.

In general, the AOI boundary does not need to be precise at all. It should simply encompass the area of the landmass where you wish to see shore points.

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Thank you for your reply @dave !
The purple area is the AOI while the blue area is the landmass.

Here are the datasets: (21.5 KB) (5.7 MB) (8.8 KB)

Thanks for sharing your data @NicoleLin . A shapefile is comprised of multiple files with different extensions (.shp, .dbf, .prj. .shx, and more). Please make sure to include all the files that share a name, not just the .shp. Thank you,

Sorry for that @dave .
Here are the full files: (27.6 KB) (6.3 MB) (21.8 KB)

No problem @NicoleLin , thanks for sharing again.

Please try adjusting your AOI polygon. Its borders should not be identical to the borders of the landmass polygon. I expect that the model had a hard time determining which edges of the landmass were inside vs. outside of the AOI because their borders appear identical.

Here’s an example of a new possible AOI polygon, in red. Use the AOI to delineate which sections of the landmass edges should get shore points, and which should not.

Also note the area circled in blue where the model was previously plotting shore points. The edge in the landmass polygon that exists in the interior of the landmass is causing this problem. The model interprets all edges of the landmass as coastline, so that interior edge must be erased, either by editing the vertices, or maybe using a tool like “dissolve” or “union”. Or finding a different data source for the landmass.

Good luck!

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Thank you so much @dave ! I misunderstood that AOI should be identical to the landmass.

I’ve adjusted the AOI layer, and it now works perfectly.

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