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Comment by pheelicks | Hacker News Reader

Hi HN, Merry Christmas to all!

I made this as a demonstration of the open data available from the Austrian government under the www.basemap.at project. The rendering engine is built on top of THREE.js and can be found here: https://github.com/felixpalmer/procedural-gl-js/

For those in the southern hemisphere, there is also a similar visualization of the national parks of New Zealand: https://felixpalmer.github.io/new-zealand-3d/

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Just want to say, love the mobile interface on iOS. Smooth as butter, super controllable, intuitive. I don’t know whether you designed it or if it came with the engine, but either way, quite lovely.

I disagree with one aspect.

Rotation doesn’t work the way it does in every other iOS UI, and so it took me forever to figure out how to rotate. On a related note, it kept inexplicably rotating whenever I would zoom in and out.

Still impressive and smooth, though. And might just be part of the library chosen.

Could you elaborate? I'm also an iOS user and find it intuitive. But of course I would, as I've spent hours developing it and can't see the issues in the way a new user would. If you move two fingers in a rotating fashion the map rotates, does it not do this for you?

Not an iOS user, but I somehow expected rotation to work if I rotate two fingers against each other (I.e. draw a circle with two fingers at the same time). But I just need to swipe sideways with two fingers.

No. If I move two fingers from side to side it rotates. If I try to rotate two fingers, nothing happens. If I also happen to also move them closer together/further apart, then it zooms. Or if I happen to end up slightly further left or right, then it rotates. The result is that when attempting to rotate 90 degrees right, it might zoom out slightly and rotate left a few degrees.

Edit: this is an image to show how I rotate things on my phone and computer trackpad: https://cdn1.iconfinder.com/data/icons/gestureworks_gesture_...

If you hold one finger in place and rotate the other around, it works. It’s a bit more subtle than the default iOS rotate gesture. If both fingers move during the rotation it gets confused with the zoom. I found the best way is to hold my middle finger static and rotate with my thumb. The opposite (holding thumb static) was much harder.

Well, I made the engine - so the answer is both :) Glad you like it. I still feel the pinch zoom could be improved though so that the focal point was at the center of the touch points, but otherwise it is pretty close to the native controls

That's is super cool. Thanks for the NZ links. Having lived in NZ after moving back to Austria, and look Arthur's Pass, brings back some good memories.

Very cool! How is the elevation data textured in this demo?

The imagery comes from the Orthofoto dataset on https://www.basemap.at/ - the actual texturing is done by the Procedural GL JS library https://github.com/felixpalmer/procedural-gl-js

Love it! Can the library handle negative elevations?

Yes

Where do you get the DEM from?

> https://github.com/felixpalmer/procedural-gl-js/

> Key features

> Batteries included elevation data. Global 3D data coverage courtesy of nasadem.XYZ

> https://www.nasadem.xyz/

Can you let the user zoom further, even if it is a bit lo-res?

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