1

I'm trying to interpolate a point file that comes from a surface water model output. Each subgrid point has an elevation, and that was used with the cell water levels to generate values for percent of period record inundated. I want to smooth out the blocky shape for a few reasons that aren't important to get into here. I'm using Qgis for a few things that I'd need a more expensive license in Arc.

So here's my grid of points. Cancel that, I'm only allowed to post two images. The points are 130' apart.

I set it to 25' resolution and ran the interpolation. This is what resulted.You can see the point layer in the background

The right third is beautiful and exactly what I want, but the left two thirds are all screwed up. I thought it might be the non-rectangular shape, so I exported a perfectly rectangular set but that didn't help. I tried adjusting everything I could think of to no avail. I tried to manipulate the projections, but I'm not very good with Q and couldn't figure that out.

The one thing I did that seemed to elucidate it was I cut out a section of points to the left of the part that worked, and tried that. enter image description here

Amazingly that worked. It looks like the TIN basically only will do a certain width. I may have a lot of these to do and really don't want to have to chop them all into pieces and then glue them back together. There's got to be a solution to this. Any ideas?

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.