Making Layers

This is the beginning of an attempt to try to document a process so people that have GeoTIFF's can produce and maybe even serve up data for WorldWind. If you have any insights or info please add on.

Things We Know

 * 1) WW's tiling scheme:,.
 * 2) Formula to go from Lat/Long to WW tile numbers.
 * 3) Nowak has a C program that uses GDAL to do this and he has another progam that packs them up so you dont have to manage zillions of files + a little PHP script to extract the correct tile from the image pyramid. Nowak released source code to DSTile (the tiler) and TilePack (packs up tiles into a image pyramid) as Open Source (BSD licensed).
 * 4) Dstile and TilePack (src)
 * 5) Dstile with what_nick's patches (13-08-2007) + Dstile GUI (bin)
 * 6) What if you were to call dstile dynamically from inside WorldWind? Urobots talks about how to do this in his blog. what_nick has been working on a dstile version that can be run as a plugin in WW (forum thread, the code is in SVN)
 * 7) Lucians OnEarth code for Apache to 'sniff' WorldWind requests, pass the request off to WMS (if needed) and cache the tiles if they are not already cached download + a few data serving scripts
 * 8) A Dstile howto on creating your own tiled imagery layer and putting it in your cache.

Things We Know We Don't Know

 * 1) How does altitude relate to a level in a layer being displayed?
 * 2) How does  and  affect #1?
 * 3) When do you know when to 'stop'? (ie. how do you know you are at 1:1)
 * 4) Even though L0TD == 2.25, how do we get larger tiles when viewing the whole earth?

Some answers came here

The Procedure for Making (As Far As I understand It Right Now)

 * 1) Obtain a georeferenced geotiff and reproject it to EPSG:4326. (or reproject with 'gdalwarp' in step 3 as you go along)(note: for those crusty-brained barnacle heads, ESPG:4326 = WGS84, and NAD83 is supposedly generally equivalent- check to verify before you take my word for it, though)
 * 2) Get the bounds of the GTiff.
 * 3) Take the lower left bounds and round to the nearest multiple of L0TD for lat and lon.
 * 4) Extract a L0TD sized chunk of the GeoTIFF starting at the coordinates of #3..
 * 5) Resample the chunk to (scale it to 512x512px or whatever tilesize you pick) and convert to image format of choice.
 * 6) Place it in the correct directory and rename the tile according to the naming formula.
 * 7) Iterate in L0TD sized chunks over the entire TIFF till you have covered the upper and right side bounds.
 * 8) Divide L0TD by 2, and start over with #3
 * 9) Stop when you are at 1:1 scale (ie your L0TD sized chunk is less than  in one of the dimensions.