What does that histogram analysis look like on an Earth-derived heightmap?
What does that histogram analysis look like on an Earth-derived heightmap?
Whilst it looks bad on the histo, it is supposed to be a 16 bit PNG so its a smallish section of 65K levels instead of 256. If this were a small bit of terrain and we were going in for a 3D through the mountains look then it might matter but wrapped on a planet then I think its going to make no visual difference at all.
Although I cant remember doing the PNG16, I would have thought that I derived it from the HF2 map so that my color and the height should have lined up. Neither might line up with the original FTPro color map or zoom map tho. If you wanted to align them then you might have to work it a bit.
Its likely to be flatish at the edges of the land mass because it would normally be something like that and FTPro has some sort of subsea flat land region before it starts to drop off steep subsea. Note my amazing lack of geological terminology there. It does mean of course that any slight Z offsetting does produce quite a radical sea-land shape from the height maps.
Holy crap. I had no idea how much I don't know.
Last week, a sci-fi RPG publisher asked me to create a planetary map and a continent map for its upcoming publication. I've been thinking in two dimensions with Photoshop as my tool.
Spinning planet video never entered my mind.
I feel something like I did when a sci-fi author friend first handed me Stephen L. Gillett's World-Building; A Writer's Guid to Constructing Star Systems and Life-Supporting Planets. There's are simple formulas for escape velocity? Tidal braking? Binary star system's gravity? I'm so in the dark!
We don't stop playing because we grow old; we grow old because we stop playing.
-George Bernard Shaw
You really don't need to worry about the nasty details of world building, as almost anything can get explained away by hand-waving.Originally Posted by Ashenvale
The real trick is to realize the polar distortion that occurs. Because of that, I like to work on base world maps using a vector tool to get the shapes correct when mapped to a sphere, otherwise the whole "greenland looks bigger than south america" problem starts to rear it's ugly head!
I think that is why many of the scifi mappers like to work on triangular/hex based projections of planets...
-Rob A>
My tutorials: Using GIMP to Create an Artistic Regional Map ~ All My Tutorials
My GIMP Scripts: Rotating Brush ~ Gradient from Image ~ Mosaic Tile Helper ~ Random Density Map ~ Subterranean Map Prettier ~ Tapered Stroke Path ~ Random Rotate Floating Layer ~ Batch Image to Pattern ~ Better Seamless Tiles ~ Tile Shuffle ~ Scale Pattern ~ Grid of Guides ~ Fractalize path ~ Label Points
My Maps: Finished Maps ~ Challenge Entries ~ My Portfolio: www.cartocopia.com
I don't know.
Can you provide a pointer to one that I can try? A quick Google search turned up ways to get heightmaps of regions (e.g. http://www.tt-forums.net/viewtopic.php?f=29&t=27052 ) but I haven't found a complete one yet.
That's one of the problems that I realized when I woke up this morning. I guess I'm going to have to write my own utilities to do the kinds of manipulations I want to do to the height values.
Do you know what scale factor was used when the translation was done between the altitude and the 64K binary values?
I'm guessing that the large spike is due to the coastal regions of the continental shelves, so presumably is near 0.
Selden
I don't have a link to a good PNG heightmap, but I used Wilbur to read the ETOPO2 data and write out an equal-area 8-bit heightmap based on that data set. The histograms for each area shown below. The hump to the left is the oceanic abyssal plain and the big spike is the coastal plain/continental shelf. A straight histogram on the Plate Caree projection of the original ETOPO2 data set has some artifacts as shown in the second one (that hump off to the right in the plate caree projection is due to polar distortion for Antarctica, most likely).
Posting Permissions
Reply With Quote
