World building using ArcGIS

[loogie]

I've been doing some more work on lakes and rivers as of late, and i hope to have some more screenshots to put up... then i'm going to start working on a climate, and possibly some soil models.

[su_liam]

There's a river draining the eastern lake that looks like it must be flowing uphill at one point between the saddle of two hills. Assuming precipitation exceeds evaporation, lakes should rise until they spill over the side.

Did you use the Bryce erosion tools on this? With the spine-like walls and slightly stairstepped channels it kind of looks like you did an iteration of erode, smoothed and then used erode again. Actually the spinewalls seem to come from the eroded tool. It's nice to see someone else using Bryce's erosion tools. On a PC, you have access to some really nice erosion tools, though. GeoControl is probably the best, followed by l3dt, but WorldMachine and Leveller are pretty good too. Probably better than the Bryce tools.

GRASS isn't working for me, so I've taken to playing with a java app called Landserf, and a UNIX toy called Terraform.

Landserf is excellent, I can import RGBA images as 32-bit elevations, and it has some excellent landform extraction tools. If nothing else I might be able to convert my 16-bit pngs into something GRASS can digest. Landserf doesn't really have any hydrology tools, though.

Terraform is a toy, pure and simple, but it's sea-level flattening tool is very useful. Better than the Wilbur exponential filter for creating continental shelves and beaches.

Erosion in terraform is problematic.

MFD flowmap doesn't work. Period. SFD does, but... it's SFD.

The river tool would be better if I could just create a pure river mask with it.

I'm playing with diffusion mediated by a flowmap with... interesting results. On a large scale map, it would make a nice swampland effect. On larger maps it could be masked out to create Chesapeake Bay type areas. Interesting.

What I'd like is an app that I could left click a point on the map and it would shade in the area where a river could conceivably flow from there. Then I could right click inside the shaded area and it would reduce the upstream area to paths a river could reasonably take to get from the first point to this point and then shade the potential downstream area.

[loogie]

thanks for the ideas..
your assumtions on bryce were spot on.. and i had lots of trouble getting it to look right.. mainly, the erode isn't exactly what i'd like to see, mainly that it differs so much by resolution... (highest resultion made crazy spline ridges that were to numerous and unrealistic, and to low was just a big large square erosion almost completely ignoring the map i had already... so i found my self switching back and forth constantly

i'm definitly going to look at some of the programs you mentioned, i'd like to try to find some much better apps for this type of thing

[waldronate]

Terraform is a toy, pure and simple, but it's sea-level flattening tool is very useful. Better than the Wilbur exponential filter for creating continental shelves and beaches.

Have you tried the Remap Altitudes filter (Filter>>Other>>Remap Altitudes...) in Wilbur? It will let you apply any profile you care to draw to the surface.

[su_liam]

Next time I have access to the Cow Computer at work, I'll try that out. I'm really not ragging on Wilbur. I love Wilbur. I'm considering investing in an emulator just to run Wilbur. Well that and, you know, WM, GC, Leveller, VD, GTS, L3DT... um, et cetera. Perhaps what I should have said was, "even better."

Actually, I kind of overlooked Remap Altitudes 'cause I thought it as a terracing filter and I've never really been impressed by terracing except in certain specialized applications. The terraces always seem a little too uniform. Now that you mention it, though, that's exactly right for shoreline flattening. One thing I was thinking about was to take the original HF add in a fairly low-frequency moderate amplitude multifractal, terrace that and then subtract the multifractal back out. That might even be good for the shorelines, might produce interesting cliffs and the like. I need to make a note to do that on my next Moo Machine run.

Again, I'm not ragging on your program. I apologise if it appeared that way.

[waldronate]

Again, I'm not ragging on your program. I apologise if it appeared that way.

I wasn't annoyed or offended in any way. There are many peculiar features hidden away in the corners of that program and most of it is at best poorly documented and I wanted to be sure that you realized that there is a tool that might be easier to use than you had suggested.