Separating traces for a topographic/ depth chart?

After doing some digging on my initial efforts, I thought I could basically force a file conversion to give me what I want (PDF to SVG or DXF). It looks like that’s the wrong approach.

I am trying to make an offset/layered depth topographic of Lake Arrowhead California, similar to below. It looks like a better route would be to select the depth lines from the map I want and then create a layer with each one. I could then import trace and cut an inside pocket to a different depth. This seems like a forceful and crude way of doing this but will work.

Can someone point me in a better direction of doing or have better way of even selecting out the trace layers from an image. Thanks in advance.

:

Here are the PDF’s I clipped from the original report, as well as the attempt from convertio:

Lake Arrowhead Depth Map Black.pdf (787.5 KB) Lake Arrowhead Depth Color.pdf (507.3 KB) Lake Arrowhead Depth Map.pdf (715.8 KB)

I recently tried my hand at a simpler version of topographical layering with an svg file I purchased and finally gave up out of frustration after trying the tracing route.
My friend helped me out and this is how he wound up fixing it: “I ended up opening the svg in inkscape and then joined each layer so they were solid shapes.”
I had no clue what inkscape was before yesterday, but im glad he did! haha

If you use Fusion360 you can carve an STL-file with no file conversion etc. Hopefully you could find a STL-file with good enough elevation resolution.

In F360 one “simply” set stepdown per pass to the required “step height” to get that kind of carve.

2 Likes

If you don’t mind getting into the nitty-gritty of GIS, there is a excellent and very detailed write up on how to carve terrain maps here.

1 Like

Hi @KenKlein,

I’ve got an app waiting for approval that accomplishes this. I took your color height map and ran it through the app and here is the result: https://easel.inventables.com/projects/DOzxgn_-hdoCOX4D8sRl4g

I’m working to get the app approved right now. Hopefully it could be live soon!

Cheers,
Ethan

3 Likes

@EthanKinney Wow, this looks great! I am bearing down and tracing a few countour lines and then exporting as an SVG through Illustrator. I’m muscling through it and it will have much less steps than this.

I’ll try and cut a demo piece to see how it comes out and I’ll share it back if it is helpful for you. Thanks a lot for sharing.

@EthanKinney I noticed that the depths are actually reversed. The shore lines are the deepest cut on this file and the deepest part is actually the highest “peak”. Is there a way to invert this since I’m carving out a lake instead of a mountain? Can I demo your program if it’s ready somewhere? Ideally, I’ll carve into 1.5 inch thick birch and then sand/stain/acrylic. It’s a pet project for fun so no problem if not.

Also, the detail is phenomenal!

Hi Ken, Yeah, I kinda noticed that too. The issue is that the height map you had isn’t a straight gradient from shallow to deep. (The color starts light, gets darker, then gets lighter) So it’s not a true height map.

If you can find a true height map for the lake, I’ll re-run it through the app for you.

The height map should look something like this:

Ahh got it. Yes, this was a depth sounding file from a reporting agency and it’s all I found and was just from a PDF report. I found a topographic chart that’s from the 90’s. If I come across one I’ll let you know so we can exercise it. Thanks again!