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Delete Siwa Oasis Heightmap
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Authored by elexis on Oct 2 2018, 10:34 PM.

Details

Summary

The heightmap was added in rP15219.

Test Plan

Check if those files are indeed useless.

Diff Detail

Repository
rP 0 A.D. Public Repository
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Automatic diff as part of commit; lint not applicable.
Unit
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Event Timeline

smiley created this revision.Oct 2 2018, 10:34 PM
Owners added a subscriber: Restricted Owners Package.Oct 2 2018, 10:34 PM
Vulcan added a subscriber: Vulcan.Oct 2 2018, 10:37 PM

Successful build - Chance fights ever on the side of the prudent.

Linter detected issues:

Link to build: https://jenkins.wildfiregames.com/job/differential/739/display/redirect

Stan added a comment.Oct 3 2018, 9:12 AM

Did you try to grep for references to these files ?
Could also run checkref.pl :)

Looking at it it seems that the height map was used to create the map and that the author left it here in case someone wanted to recreate it.

I'd say we move it to the art source repository :)

smiley added a comment.EditedOct 3 2018, 9:23 AM

I did grep it.
Could also move it to the maps/skirmish directory which already contains some heightmaps like the Greece one. But I never saw the point of keeping those heightmaps in this repo. Art repo seems to be a better place.

asterix accepted this revision.Oct 3 2018, 11:03 AM
asterix added a subscriber: asterix.

I agree with Stan that it could be moved to art repo and with Smiley in a sense that it is unused.

This revision is now accepted and ready to land.Oct 3 2018, 11:03 AM
smiley requested review of this revision.Oct 3 2018, 1:41 PM

Put it to Stan's review queue as it would be him who would make the final decisions.

Stan accepted this revision.Oct 3 2018, 2:24 PM

I'll move it to the art repository for A24

This revision is now accepted and ready to land.Oct 3 2018, 2:24 PM
elexis added a subscriber: elexis.Oct 3 2018, 3:51 PM

Bonus question: Did michael leave any word about the source of this file on the forums or irclogs or can we assume that to be copyrighted material like was with many of his or mine heightmap commits as well, thus warranting to delete/reproduce the map as well (given that there was no copyright claim in the concerning commit and we already had to delete 12 heightmaps for that reason)?

@wowgetoffyourcellphone Do you remember where it came from ?

smiley added a comment.EditedOct 4 2018, 7:54 AM

I think it would be wise to be prudent about this. Better safe than sorry.
I would try to reproduce the map with a heightmap from viable sources.

smiley added a comment.EditedOct 4 2018, 9:28 AM

Is that heightmap accurate? I could find no resemblance with that heightmap or the skirmish map to the real place.
https://www.openstreetmap.org/#map=11/29.2325/25.5408
Edited for a better more trustworthy link.

Stan added a comment.Oct 4 2018, 10:50 AM

If you feel like redoing the map that's great but maybe it's a bit Overkill ? :)

elexis added a comment.Oct 4 2018, 1:03 PM

(
Did a quick lookup since I have the related data on my disk anyway:
Couldn't find anything in irclogs in 2014 for "siwa", "nasa", "srtm", "heightmap", "topography" or "Mythos_Ruler".

Blue Marble data looks different, can copy&paste from lower_nubia.js etc.:

wget https://eoimages.gsfc.nasa.gov/images/imagerecords/73000/73934/gebco_08_rev_elev_C1_grey_geo.tif
lat=29.205278; lon=25.519444; width=10
lat1=$(bc <<< ";scale=5;$lat-$width/2"); lon1=$(bc <<< ";scale=5;$lon+$width/2"); lat2=$(bc <<< ";scale=5;$lat+$width/2"); lon2=$(bc <<< ";scale=5;$lon-$width/2"); gdal_translate -projwin $lon2 $lat2 $lon1 $lat1 gebco_08_rev_elev_C1_grey_geo.tif lower_nubia.tif;
convert lower_nubia.tif -resize 512 -contrast-stretch 0 lower_nubia_heightmap.png;
eog lower_nubia_heightmap.png

https://www.openstreetmap.org/#map=11/29.2325/25.5408

That's not a topographic map, but the bodies of water don't match.

Perhaps it was SRTM. But it seems plausible that the heightmap comes from a different location to begin with.
As the image was mostly likely downloaded from somewhere and not drawn manually, safer to treat all files of the derivative work equally (i.e. either document this as a possible copyright violation and get a clarification before acting or delete the derivative work to rule out a copyright violation).
)

smiley added a comment.Oct 4 2018, 1:39 PM
lat=29.205278; lon=25.519444; width=5;
lat1=$(bc <<< ";scale=5;$lat-$width/2"); lon1=$(bc <<< ";scale=5;$lon+$width/2"); lat2=$(bc <<< ";scale=5;$lat+$width/2"); lon2=$(bc <<< ";scale=5;$lon-$width/2")
gdal_translate -projwin $lon2 $lat2 $lon1 $lat1 gebco_08_rev_elev_C1_grey_geo.tif siwa_oasis.tif
convert siwa_oasis.tif -resize 512 -contrast-stretch 0 siwa_oasis.png

What I had used, Couldn't get something related even after tweaking a lot.

Stan added a comment.Oct 5 2018, 8:17 AM

Michael says this comes from the NASA. Don't have a link but I don't think their license is compatible.

elexis added a comment.Oct 5 2018, 2:54 PM
In D1646#65207, @Stan wrote:

Michael says this comes from the NASA. Don't have a link but I don't think their license is compatible.

Would also be good to know from which location it came from, since it doesn't appear to be Siwa Oasis. If we know the location, one could compare.
Without further information, it is at least uncertain whether this image and the pmp file are a derivative work violating the copyright of the author.
I think most NASA material is public domain, most SRTM versions were usable for us (just not the one specific modified SRTM version we had used).

Stan added a comment.Oct 5 2018, 3:21 PM

I can ask him again but it's unlikely he remembers more than this.

elexis retitled this revision from Remove out-of-place unused heightmap to Delete Siwa Oasis Heightmap.Oct 11 2018, 4:37 PM
smiley added a comment.EditedOct 11 2018, 4:52 PM

https://visibleearth.nasa.gov/useterms.php
Highly likely this one is public domain, but he could have took it from a copyrighted source too.
Regarding the accuracy, we could always scrap this one and remake the real thing.

elexis commandeered this revision.Oct 11 2018, 5:00 PM
elexis added a reviewer: smiley.

From a visual comparison we can confirm that the png file is the same as the pmp file, or at least certainly a "derived work" under US copyright.

It's not NASA Blue Marble of Siwa Oasis as we tested that last time.
If it's NASA SRTM of Siwa Oasis as we can see 8 or more SRTM sets with some clicks in https://earthexplorer.usgs.gov/ and they all look equal but entirely different from the committed png.

The heightmap might come from NASA, since most publicly accessible maps come from there. But it would have to be some other location of the earth that was just claimed to be Siwa Oasis.
Or the PNG was reworked from top to bottom up to the point irrecognizability, creating entirely new hills and lakes, which seems unlikely.

The author doesn't recall the exact origin of the heightmap and has practiced taking things that are free as in beer but not free as in GPL v2+ / CC-BY-SA before.

The burden of proof is on the one committing the map that the licensing is correct.
The map is not bad, so it's loss that it has to be removed from the repository until someone can clarify this or write some fancy algorithm to find the location of that heightmap.

(There is a scenario map called Siwa Oasis which looks entirely different. More realistic if that map is centered around that western smaller oasis.)
That one doesn’t have to be deleted ofcourse. Looks like it was handmade. Just putting it out here.

Asked via PM for circumstancial evidence like software, image editor, location.

No further information available other than a heightmap of an unknown location of an unknown NASA elevation map. Supposedly multiple heightmaps superimposed and one of them being from Siwa Oasis.
But I can't recognize the location from NASA heightmaps that all look very similar.
From a visual inspection, and a comparison of the resolution to the blue marble heightmaps, I would say it's a random mountainrange with black water and white hills being added in an image editor.

Siwa oasis google maps:

Siwa oasis map in question:

Siwa oasis scenario map:

Siwa oasis blue marble topography:






Siwa oasis map in question:

Blue marble composites random USA mountainrange:

This revision was automatically updated to reflect the committed changes.
Owners added a subscriber: Restricted Owners Package.Oct 19 2018, 11:06 PM