Terrain viewer issue with Ease of Access settings

Boyd

Boyd

Administrator
Staff member
Site Administrator
Jul 31, 2004
9,826
3,005
Ben's Branch, Stephen Creek
(Note: The posts in this thread were split from another thread on a completely different topic.)

Summary: If you're using display settings that are different from your screen's default settings, it may cause problems with the terrain viewer. These may appear as "spikey things" (see image below) in some locations or "contour lines" in others. It will also cause only part of the image to be displayed. Basically, it happens if your screen doesn't show exactly one dot for each pixel. Your graphics card needs to scale the image to do this, which affects the number of pixels displayed and can create image artifacts. One solution is discussed at the end of the thread but a different one might be required in other cases
_______________________________________________________________________________________________________

bobpbx said:
The first image below is from the Mid-Atlantic Lidar 3D, and the second is the 3D terrain viewer.
Click to expand...

1689098763384.png


1689098823569.png


___________________________________________________________________________________

When did you take that terrain viewer screenshot? Was it today or awhile ago? Because I don't think those "spikey things" are actually in the map anymore. Those look like the errors that I spent so much time fixing. Not sure of your exact location, but it appears to be close to here:

https://boydsmaps.com/terra/#39.724...1577/423/-1014/35.25/4.4/3d/grayscale/0/0/z17

I don't see any errors like that, does it look different when you click that link?

Screen Shot 2023-07-11 at 4.13.03 PM.png


If this is an area you have spent time looking at in the past, I suspect that your browser has cached the old, bad elevation data. Clearing the cache should (theoretically) fix that, which would be worthwhile because the new dataset is much, much better. Always possible that I missed some errors, but I don't think so.

BTW, as a general note for everyone, if you use the screenshot button (camera icon) at the top right in the terrain viewer, it will download the exact same image you see, but a "clean" version without the compass, menus, buttons, crosshairs, etc.
 
Last edited:
Boyd

Boyd

Administrator
Staff member
Site Administrator
Jul 31, 2004
9,826
3,005
Ben's Branch, Stephen Creek
Has to be old data then or I would see that too. The Windows version of Edge holds onto cached data like a little dog holds onto a pants-leg. :D

Can you try opening the same link in Chrome, Firefox or some other browser?
 
Boyd

Boyd

Administrator
Staff member
Site Administrator
Jul 31, 2004
9,826
3,005
Ben's Branch, Stephen Creek
That's bizarre, you're seeing the ghost of old data that no longer exists! Just tried Chrome - no spikes here. I wonder if Edge and Chrome share the same cache? Edge is also based on Chromium, but I'd think it would have private data.

Does anybody else see these spikey things? I mean, I spent a considerable number of hours fixing those problems, so *I* mind if they still appear! They are invisible on the 2d map in the regular app, but will give wrong elevation readings if you pass over them.

Perhaps some graphics card glitch? Seems to me we both have the same Intel UHD 630 integrated graphics chips however.
 
Boyd

Boyd

Administrator
Staff member
Site Administrator
Jul 31, 2004
9,826
3,005
Ben's Branch, Stephen Creek
Looking at my code again, I was thinking that different operating systems/browsers/graphics cards may have different default values that could cause a problem like you're having. Specifically, if your system always applies anti-aliasing to images, that could do it. So, I added some code that should specifically disable anti-aliasing of the elevation tiles. See if that makes a difference with the link I posted above. You may need to clear your cache again just to get the browser to load the updated code.

Also, this might shed some light on what is happening. What do you see when you look at this view of Apple Pie Hill?

https://boydsmaps.com/#17.80/39.807307/-74.589518/mbx3dmidatl/-84.00/79.40

This is how it looks for me. But before I fixed the elevation dataset, it was all messed up, there was a big hole in the mountain (a section where the elevations suddenly dropped 50 feet or so).

Screen Shot 2023-07-12 at 10.32.10 AM.png
 
bobpbx

bobpbx

Piney
Staff member
Oct 25, 2002
14,658
4,836
Pines; Bamber area
Boyd said:
Looking at my code again, I was thinking that different operating systems/browsers/graphics cards may have different default values that could cause a problem like you're having. Specifically, if your system always applies anti-aliasing to images, that could do it. So, I added some code that should specifically disable anti-aliasing of the elevation tiles. See if that makes a difference with the link I posted above. You may need to clear your cache again just to get the browser to load the updated code.

Also, this might shed some light on what is happening. What do you see when you look at this view of Apple Pie Hill?

https://boydsmaps.com/#17.80/39.807307/-74.589518/mbx3dmidatl/-84.00/79.40

This is how it looks for me. But before I fixed the elevation dataset, it was all messed up, there was a big hole in the mountain (a section where the elevations suddenly dropped 50 feet or so).

View attachment 20228
Click to expand...


1689178363185.png


Above is what I get for Apple Pie hill on Edge, but even though I cleared the cache on Edge and Chrome, your other link did not clear up. Here it is under chrome. And I restarted on each after clearing the cache.

1689178682434.png
 
  • Like
Reactions: Boyd
Boyd

Boyd

Administrator
Staff member
Site Administrator
Jul 31, 2004
9,826
3,005
Ben's Branch, Stephen Creek
The Apple Pie screenshot indicates you're using new data and not the cache, which is good. But is that a location that you hadn't viewed for awhile? If so, then it wouldn't be cached. Looks like no change at the other link. Oh well, it was worth a try. The thing that's odd about those spikes is that they're higher than the other terrain. The errors I saw in the old dataset were all lower. Weird.

If anyone else happens to see this thread, have a look at the terrain in this link. Do you see smooth terrain like my screenshots above, or spikes like Bob's?

https://boydsmaps.com/terra/#39.724...1577/423/-1014/35.25/4.4/3d/grayscale/0/0/z17
 
Boyd

Boyd

Administrator
Staff member
Site Administrator
Jul 31, 2004
9,826
3,005
Ben's Branch, Stephen Creek
Something is very odd there. This also looks like the old data. So I'm stumped. Could be that you are somehow still getting cached data, or it might be that your browser(s) are processing the elevation tiles in a way that creates these artifacts. I can't reproduce that using Windows myself, but the fact that I'm using Windows in a virtual machine might be a factor.

It really would help if a few other people would post what they see at these links.
 
You must log in or register to reply here.
Top