View Full Version : Digital map to .png or .jpg or .gif

07-16-2012, 10:35 AM
Hello everyone,

I've been trying software and waiting for maps to download and i can't come to the end result i want so that's why i'm making this topic.
I want to use the ETOPO1 format ice-surface map from http://www.ngdc.noaa.gov/mgg/global/global.html as a greyscale heightmap. I have downloaded and tried GEODAS and was able to get a blue shade map of the world but i can't export it as an image in it :( screencapture won't work because the map is a way bigger resolution as my screen supports. And scaling it up afterwards would get quircky.

An other solution would be to somehow merge the heightmap and bathymetric map from http://earthobservatory.nasa.gov/Features/BlueMarble/BlueMarble_monthlies.php but the color shades would mix up i guess but if it's possible i'm open to it. I don't expect it is but just to be sure.

So yeah, i basiclly am looking for a heightmap (as an image file, TIF?) of both under and above water terrain, with the ice cap on top of it for the poles in a size of atleast 21600*10800. I'm OK with downscaling. I'm willing to install freeware or trial software whatever. I'm just seriously annoyed at this point i couldn't figure it out after 5 hours of googling and trying stuff out that i have to bother you with the question :(

Kind regards,


07-16-2012, 12:17 PM
I think I can do this - gimme a couple hours...

07-16-2012, 12:32 PM
That would be seriously awesome. Thanks in advance for even trying! :)

07-16-2012, 05:06 PM
Ok result time:

View this

Download this cos its 320Mb

Once you have downloaded it then ill remove it as its a bit of a burden on the ole web site space.

It should be a 16bit PNG and should have values in accordance with the values in the DEM file inc the "no data" value. I dont have much to view this as a 16bit greyscale PNG (Photoshop should be ok tho) and I would have used an HF2 but it does have all the sub sea bathymetry included. In fact looking at Africa is notably & surprisingly flat in some regions. The plains I guess.

This seems to be the Amazonian basin.

If you get stuck with the 16bpp then you can use Image magick to convert it. I used it to get it from my raw grey format to the 16 bit greyscale PNG so it does work. Its also free and mighty useful. I used my own tool to decode the file on the site tho.

07-16-2012, 05:19 PM
i can see directly the andes and the sea next to it are nearly the same shade of color grey. This is impossible, i'm sorry to say but this won't work.

the edges of the rings are contrast with the supossedly higher area which lowers for a bit and poof it's high again. This wouldn't work. I appreciate the work, i really do, but this is not what i'm looking for, kind of bummed i have to say it.

But well, i need a solution for the problem and this isn't it so the topic isn't solved :(


In the picture above the himalaya and andes are clearly visible white, this means they are very high, ever so slightly the colors turn to black indicating it's lower. But the sea is used as bottom in this heightmap and doesn't account for the ocean floor. In the ETOPO1 they are both in the same image, but i can't use the color scheme. I have to proces it with software which only takes greyshades heightmaps. -it's non optional i use this software-

so i'm sorry to say that image won't work. I really appreciate the work you've put in, unfortunattely it's not what i'm looking for. i'm sorry to say.

07-16-2012, 05:26 PM
Yeah the image I have uploaded is 16bits and when you view it like the upload then every 256 shades and it reverts back around to black and climbs back to white again. I.e. my image is 256 times as accurate as your greyscale cos yours is in 8 bits. If you want to drop the height resolution then you can do that with image magick.

Its no problem. Now that I have it converted ill convert it some more to HF2 and generate the 8 bpp PNG file. If you have photoshop tho you might still want to grab that file cos it might look right in that.

07-16-2012, 05:31 PM
Ok thats done. It will look like this. Its going to be 35Mb so gives you some idea of how much lower vertical height res its going to be. The new one is called Topo8.png in the same ftp dir. Just give it about 3 mins to get it up there.

07-16-2012, 06:17 PM
i guess seen the size it isn't 21600*10800 pixels as i requested. The problem is that 1 pixel in the original is 2KM, loosing 1 pixels is loosing 2km in height variation, when it comes to steap hills that is a lot.

Can i do the proces myself? i have photoshop. 8 bit is good enough.

07-16-2012, 06:25 PM
Seriously... it is...


07-16-2012, 06:41 PM
Wow. I must be even worse in file formats than i already thought. Awesome, thank you. I'm going to try it out and be sure to let you know how it worked out!

07-16-2012, 06:48 PM
Cool, yeah, post some piccies of the results !

07-16-2012, 07:14 PM
It worked FABIOUSLY. This image just flushed through the software, very much unlike the oversized PNG's (540MB) i was using. Dude, you are a god in my book now. And all the data is in it, i very much like to know how you are able to put all of it in such a small file size... are there keywords i could search on google or do you know of tutorials and such? I can't believe all the data was in such a tiny file... Do you do this normally in a professional capacity?

I'm using it to make a world map for the game called Minecraft. Basicly i'm creating a 1:2000 scale world for it for players to plan on and build like replica's of their houses on. A wall block would be 2KM thick though so building can't be anywhere near scale, but it's fun to go build on your country ingame and battle with your neighbours and such. It's really a very populair indy game, you've probably heard of it because the succes -seen it's an indy game- did also spin some articles in mainstream media. I'm just making the map as a fan of the game, the community is awesome.

I have posted a topic on a game related website -without the bathymetric height differences- and almost 15.5k people have seen the topic (the ones who where measured, but you have to subscribe for it and be logged on to be counted, the actual amount of people who've seen it is probably more around 50~75k players) and i recieve a huge amount of comments that they already love it eventhough it's not even finished/published.

I'm not going to do any fancy stuff with it worth of showing off to the world. But you make a lot of people even happier now the sea has height differences to! :) I'm totally willing to credit you for the awesome work but you might get overrun by teenagers asking to convert a map for free, like me. Only difference i'm not a teenager xD I'll leave that call up to you.

Many, Many thanks again! This is totally awesome, the detail is WAY WAY better as i expected. Infinite internet credit points to you :)!

07-16-2012, 07:23 PM
I am kind of curious now how the 300MB sized map looks and if it will affect the detail of the map when i run it through the software. Downloading that one as well if you don't mind :)

unfortunatelly the bigger map shows like it was in the thumb, with colors being off. Im going to look into imagemagick next thing tomorrow :)

07-17-2012, 05:12 AM
I'm glad that worked out for you. In terms of tutorials I wrote the main one here about the technical side of images - all the non artistic stuff to do with file types, resampling and all that kind of thing.


We also have monthly mapping challenges where it goes to vote - if you have browsed around the site you must have seen that. Well one month about 2 yrs ago we had one where there was a really strict file size limit and people had to map the best they could do in that file size. A lot of discussion and tips were posted about how to reduce the file size in those threads. But basically for the 35Mb height map I posted its merely an 8 bit greyscale PNG.

We have heard of Minecraft and got posts about that when it was released. Though I have not seen Notch on these boards hes a popular web programmer. If I may Id point you at some other resources too. There is Joe Slayton who writes "Fractal Terrains" which make large fantasy world height maps which you could use to import in your minecraft worlds. He also writes Wilbur the free height map conversion & manipulation tool as well which is very popular around here. Another interesting link you ought to check out is "Outerra" which is an in development 3D world terrain viewer which is just unbelievable until you have tried it and it certainly stomps all over minecraft though minecraft is more about building stuff and Outerra is more about exploration in a fixed landscape.

I write ViewingDale which is a 2D world building app where instead of building in blocks you build in images layered up. Try a youtube search or see my sig. Im also involved with the Me-Dem work which is the middle earth digital elevation model project to make an accurate height map / 3D terrain of middle earth. The Middle earth we have at the mo is 40K pixels square and 16bit height res and its been put into Outerra and looks great but Outerra shows up the errors in it because you can get right in there and up close. We use ViewingDale to browse the 2D maps and a lot of custom tools to modify the height maps which is what I used for this file. Wilbur as mentioned is pretty darned good at doing a lot of conversions though whether it would stay up with a 20K wide file I dont know. Certainly its very capable with smaller files and handles a lot more formats that I use.

If you want to credit me you can but you might be just as well pointing them to the guilds front page. If they are interested in making maps - whether using minecraft or something else - then this is the place to be !

As for the higher res 16bpp PNG. I dont have any means to check the image. I use a height format called HF2 of which was written by Aaron of L3DT - another good link to check out - the Large 3D Terrain generator. HF2/HFZ stores its data in a compressed tiled and packed floating point so its quick and easier to manipulate compared to these large PNG, GeoTIFF style formats. I believe tho that the 16bpp PNG file does contain the information you need for a more accurate height map but its well possible that its wrong. I could upload the HF2 file which is definitely right but theres not much software around to read that. Theres not much point in using ImageMagick to convert the 16bpp file to 8bpp since I posted the 8bpp version but you could scale it using some custom greyscaling curves to get to your 8bpp in a different way to the linear one I used. I.e. you could use more shades of grey near to land and compress the sea into a smaller range.

Anyway, post some minecraft pics too.

Heres the MeDem gallery showing all sorts of stuff inc Outerra, ViewingDale, my GeoTerSys etc.