Saturday, October 28, 2006

Thoughts on WMS-C

Chris notes his thoughts today about the WMS-C tiling spec that's currently being worked on through OSGeo. He proposes a fairly cheap solution by using Amazon S3 to host the tiles with all it's capabilities. So, Chris—with Schyuler's notes—broke down the cost of caching the Landsat 7 dataset with S3.

"Sure its not free, but it sure as hell is cheap … Based on Schuylers calculation from the wiki article,

Taking 15m pan-sharpened Landsat-7 composites as an example, at a tile size of 512 x 512 pixels, each tile would be about 7,680 meters on a side, or about .0625 degrees across. Plugging in the other values, we get a maximum of 22,118,400 tiles in the layer.

"Assuming the optimum size of 64kb is reached per tile, we’re looking at 1415.577gb of physical storage. Lets take a wild guess of 50gb of transfer per month, with the actual tiles only be updated annually and we have the following,

$0.20 * 1415 = $283 to initially upload the cache

$0.15 * 1415 * 12 = $2547 for a years worth of storage

$0.20 * 50 * 12 = $120 of user transfers (eg. downloads)

Total: $2950"

Chris goes on to make a hint that Refractions perhaps get in on sponsoring this. I commented on Chris' blog that "why doesn't USGS or NASA just pay for it?" It's a drop in the bucket for them.


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