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3D map of the Czech Republic, made from 12.5cm/px imagery (2017)

mapy.cz

11–20 of 123 posts

Re: 3D map of the Czech Republic, made from 12.5cm/px imagery (2017)

#11
Impression for those that don't want to wait for the application to load: https://lucgommans.nl/tmp/prague3d.html (5MB, 10s mp4 of a square in Prague)

A bit choppy because of the basically nonexistent GPU, and I just made it with xdotool (moving the mouse straight/consistently) while recording the screen, but I'm quite impressed with the level of detail of this 3d map!

Re: 3D map of the Czech Republic, made from 12.5cm/px imagery (2017)

#12

Awesome. Breathtaking. But the imagery isn't from satellite data, is it? Must be from airplanes.

Indeed, something like 25cm or better is typically shot from airplanes. I don't remember what the physical limit is for image quality given a reasonably sized spy satellite (iirc it's around the 20cm mark), but commercially at least, the high quality imagery is all airplanes. Governments often commission such planes to fly ~yearly at something like 10 cm, as well as commissioning height maps[1], but the very good stuff is not released to the public for privacy reasons. I think the best I've ever seen is 15cm.

The point clouds from those height maps alone, though, I already find to be quite interesting/revealing. You can see the contours of e.g. a tree exactly, even without having any imagery laid onto them: https://snipboard.io/tPsRBo.jpg

[1] For those that can read Dutch, how the Actueel Hoogtebestand Nederland is made: https://www.ahn.nl/ahn-the-making-of

Re: 3D map of the Czech Republic, made from 12.5cm/px imagery (2017)

#13
post #9

And the practical application of data like these: https://prehrada.hrach.eu/en.html

This looks very useful and would bring electricity prices way down. The best time to start building would have been years ago, the second best is today!

Re: 3D map of the Czech Republic, made from 12.5cm/px imagery (2017)

#14

Nice! (Note: It takes forever to load, but it's worth the wait.) The not yet loaded tiles give a interesting "thirteen floor" effect :) I found a glitch https://imgur.com/a/6Oh3AQn https://en.mapy.cz/zakladni?m3d=1&height=1100&yaw=234&pitch=... It looks like a quarry. Is the wall too vertical just in the border between tiles? Did they dug that part just between photos?

Yes, it is owned by a company I work for. It is an open pit coal mine. Not a glitch.

Re: 3D map of the Czech Republic, made from 12.5cm/px imagery (2017)

#16

Awesome. Breathtaking. But the imagery isn't from satellite data, is it? Must be from airplanes.

I guess the geometry is also from lidar/airplanes. As example case in Slovakia: https://zbgis.skgeodesy.sk/mkzbgis/en/teren?pos=48.262614,17...

Re: 3D map of the Czech Republic, made from 12.5cm/px imagery (2017)

#17

Why don't map sites ever publish 3D as topo lines overlaid on a flat 2D map? It's computationally much cheaper, and it's not too hard to learn to read a topo map, as long as the elevations are printed in a reasonably dense manner.

Why sacrifice accessibility and usability to save on a bit of computation?

Re: 3D map of the Czech Republic, made from 12.5cm/px imagery (2017)

#18

Why don't map sites ever publish 3D as topo lines overlaid on a flat 2D map? It's computationally much cheaper, and it's not too hard to learn to read a topo map, as long as the elevations are printed in a reasonably dense manner.

Because for a layperson, an actual 3D map is much easier (and prettier) to read than a topo line map.

Re: 3D map of the Czech Republic, made from 12.5cm/px imagery (2017)

#20

Why don't map sites ever publish 3D as topo lines overlaid on a flat 2D map? It's computationally much cheaper, and it's not too hard to learn to read a topo map, as long as the elevations are printed in a reasonably dense manner.

Why sacrifice accessibility and usability to save on a bit of computation?

Don't get me wrong, I think it would be super cool to _also_ include a topographical map feature for those who wanted/needed it, but I don't expect most people would be able to use it in lieu of a simple, visual 3D view.
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