Waldo Jaquith

I'm trying out Postgres/PostGIS, using [these data-loading instructions](http://suite.opengeo.org/docs/latest/dataadmin/pgGettingStarted/shp2pgsql.html). That's gone fine so far (with the surprise requirement that I have to run `CREATE EXTENSION postgis` up front), but my efforts...

Ah-ha—this works: ```sql SELECT gid, id, gridcode, zone FROM conus WHERE ST_Contains( geom, ST_Transform( ST_GeomFromText( 'POINT(-78.2 38.5)', 4326) ,4269) )=true; ``` This is running 19–25 ms per query. That comes...

No, this was going really badly, for reasons that I didn't document and cannot remember, though in my defense I was on some very powerful painkillers for the entire week,...

Theory: I can use [PRISM's geodata](http://www.prism.oregonstate.edu/projects/plant_hardiness_zones.php) to generate static files for lat/lon pairs at a reasonable resolution. Then queries can be issued at a prescribed level of specificity (e.g., no...

The simplest way to do this is probably via the provided ARC/INFO ASCII grid files. This represents Puerto Rico as 557 columns by 170 rows, or 94,690 files for that...

Of course, it remains to map each cell to a physical location. But this looks easy. The opening stanza of each ASC files opens with metadata like such: ``` xllcorner...

One concern that I have is about the resolution that this yields. Is it reasonably round-able? Will there be collisions? How to handle them?

The continental U.S. is 7,025 columns by 3,105 rows, or 21,812,625 files. That certainly is a very large number of files. Hawaii is another 1,077,008 records, and Alaska another 808,505...

It turns out that these files are at different resolutions. The continental U.S. is at 800-meter resolution, Hawaii and Puerto Rico are at 400-meter resolution, and Alaska is at 4,000-meter...

If we had a resolution of 0.01 degrees, that would leave us with about 14,666,080 records for the continental U.S., or 140 times more than at 0.1 degrees of resolution.