Usage in a GIS

Usage in a GIS

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Mon May 31 15:58:26 2021   by   Will
I'm curious as to whether I would be able to use the output maps as DEMs in a GIS to generate rivers via flow accumulation tools. I've given it a go in QGIS, but the outputs have been meaningless. Is it because there is no coordinate reference system? Or is it something else that makes the map unusable as a DEM? For reference, I'm attempting to use seed 6183934 on the square projection as a greyscale map.
 
Mon May 31 16:15:38 2021   by   Torben
I don't really know enough about GIS to know.  But I suspect that you are right that a problem may be lack of a scale both for distance and height.  You might have to scale the numbers output from the program to what the GIS expects.

For example, typical altitudes in the program (for historical reasons) range from about -0.1 to +0.1.  This would correspond to about +/- 5km, maybe +/- 10km. So if the GIS expects altitudes in meters, you should multiply by 50000 or more.
 
Mon May 31 19:49:50 2021   by   Will
The altitude comment is odd, because when I created a single-band colour scale for what was effectively the raster layer, it gave values from 0 to 233.
 
Mon May 31 19:49:50 2021   by   Will
The altitude comment is odd, because when I created a single-band colour scale for what was effectively the raster layer, it gave values from 0 to 233.
 
Tue Jun 1 10:35:53 2021   by   Torben
O.k.  If you use a colour map, you can get any scale you want.  I was talking about the values used internally.
 
Mon Jun 7 01:12:06 2021   by   Ausk
i was able to implement this in a leaflet map

i run the program itself by using javascript to build the command line arguments for zoom, long, and lat then set the grid content to an "image" that is really a php file that sets its own mime type to an image.

then the php backend page runs the arguments passed via GET to exec() with a -o of temp.bmp then at the end readfile() to spit out the product into the browsers expected image. works well enough but the nature of waiting for everything to generate in real time makes it a tad slow even on localhost.

if one were to permanently save these files as they were generated im sure that would remedy this.

im not sure as to the limits of the base executable however i would posit since its fractal based it could zoom infinitely? regardless that is what i extrapolated from the behavior displayed by my code. was quite interesting to see a whole procedural world in a GIS map in real time that could change from a single variable ( ?seed via GET )
 

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