Resolution of color tiles

[Larry]

Hi Scott,

A quick question: what are the resolutions of the different color tile sets? My eyeball estimate was that the .003 color set had a resolution of about 1.6 feet (pixels were 1.6 x 1.6). What's the correct value for the different sets?

Larry

[ScottMorris]

It depends, both on what state you are in and your latitude.  The color aerials are not in a UTM projection, so a precise meters per pixel cannot be computed.

The numbers in the tilesets are lat/long degrees per pixel and are a constant.  It's just that the size of a degree changes depending on latitude.

That's the long (and perhaps confusing) answer.

Short answer: Most of the color tilesets are roughly 1 meter per pixel or better, which is the standard for NAIP data. 

[Larry]

The numbers in the tilesets are lat/long degrees per pixel and are a constant. 

Hi Scott,

I must be missing something; here in the NW, one degree of latitude is ~60 NM. This converts to 11120 meters. If a color pixel is 0.003 degrees, this comes out to 333 meters. Is it perhaps that each tile is .003 degrees? Naw, I must be doing something wrong!

Larry

[ScottMorris]

My mistake, it's the size of the tile, so divide by 512 pixels ~= 0.65 meters per pixel (in the northwest at least).

Thanks for pointing that out!