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.


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.

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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:

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



@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!