^ You already have! I think that I may have contributed to some confusion about that. When I first started looking for a way to do a live lookup of land classification for a given spot on Earth via coordinates, I immediately found Google Earth Pro, which I posted an image of several posts back in this topic. In that image, the software displays high-resolution satellite images of Earth, and a second layer of classification data. From that I concluded that data sets included both the photographic data and the land classification data. Which seemed annoying because I don't need the photographic layer at all, but rather only the land class data -- but it appeared that I would be forced into downloading both. That is -not- true of the GeoTiff data "sets". The tiff files are just tiff files but they do not represent photographic images. They are images of the land classification values. There aren't two sets of data in the GeoTiff format, but only one set -- the land classification values in sequence within a tiff file. The tiff file of GlobCover 2009 data which I resized and posted for you -is- a GeoTiff. It has no photographic information at all, just the land class values in place of photographic pixel values. That's the only difference in a GeoTiff. It's still a proper tiff file. The pixel data is not of a photo, but rather classification values.meynaf wrote:but i can't handle GeoTiff files at all
You're right about the somewhat futile nature of trying to translate real-world land into Freeciv maps, but short of completely changing the entire Freeciv software to support a totally different map structure, I don't see any options other than trying any one of several imperfect methods... In v2.6 at least, there are only 14 tile types.
ocean
deep ocean
lake
inaccessible
arctic/glacier
desert
forest
grassland
hill
jungle
mountain
plains
swamp
tundra
Of those, only a few types inherently indicate elevation/depth: Four land: mountain, hill, plains, grassland. Two water: ocean, deep ocean.
A few others -may- indicate the extent of elevation when used near some of the prior four: arctic/glacier when used near mountains may indicate high elevation. Forest used near mountains may indicate lower elevation of mountains (below the tree line.)
A couple indicate relative elevation to nearby tiles: Swamp indicates the swamp is lower elevation relative to adjacent flat-land tiles which aren't swamp/lake. Same with lake tiles, the lake must have lower elevation relative to nearby flat-land tiles such as grassland or plains.
But all of it can be rendered nonsensical in a Freeciv map, even during game-play. Engineers can create a swamp in the middle of a desert mountain range, for instance. A map can have a lake tile in the middle of the surface of Antarctica, in which a boat can be produced, despite that the lake should be frozen solid.
In short, there is no perfect way to translate varying real-world terrain maps into Freeciv maps. We are left with two choices: just translate the land cover classifications into single tile types without trying to make it make sense, or try to use a consistent system to represent more information about the land than individual Freeciv tile types convey such as by consistent/systematic use of mixed terrain tiles to indicate something more than individual tile types convey. Mountains mixed with forest to show that the land is -both- mountainous and forest-covered, for example. ::shrugs::
Then there are some additional issues, such as rivers that run uphill.