Grid Mapping in the USA

January 10, 2009 2:11 PM

Help me find or create a grid with GPS coordinates of every square mile of the USA. Can I use Expert GPS or Google Earth to do this?

Has this been done before by government or other entities (Google Maps, etc.) What are some problems in creating such a grid? Can I use Expert GPS to do this?

posted by Xurando to grab bag (6 comments total)

GPS coords are just latitude longitude pairs. Your grid is simply a map with lines of latitude and longitude drawn, in whatever increments you prefer.

The only "problem" with such a map is that you're projecting a sphere onto a flat surface, so that depending on the projection you choose, the line will not necessarily be straight on the the projection. There is plenty of mapping software to do these projections for you; for the completely casual user, xearth will produce maps of several projections, with arbitrary lines or points or circles around of specified latitudes and longitudes. More professional GIS poducts, both freeware and proprietary will do more.
posted by orthogonality at 2:28 PM on January 10

The Census Tiger/Line Shapefiles probably have what you need, but I know jack-all about GIS so that's about as far as I can help.
posted by exogenous at 2:50 PM on January 10

Has it been done? Well, yea, it's the 7.5 minute map series from the USGS...or, well, any of the series maps, which are tagged by lat/lon. It's known for everyplace in the everyplace, but I don't know of an all-in-one map per se.

Not sure what your intentions are, but UTM mapping is pretty much what you're describing. It's also incredibly easy, and already done, and kinda cool actually. I can kick some ass w/ a map and compass and regular degrees on a course, but UTM is the sheeps alfalfa when it comes to sharing coordinates.
posted by TomMelee at 7:25 PM on January 10

ArcGIS can easily do this (with an extension). Would you want a square mile grid to start at a specific coordinate or do you want all of the land area of the US covered by the grid of 1x1 mile lines?
posted by buttercup at 8:01 AM on January 11

What I am looking for is an already established grid of 1X1 mile lines across the USA, located by GPS coordinates. Additionally, I would like someone to be able to plug in their coordinate and be taken to the specific grid square.
posted by Xurando at 9:09 AM on January 11

so... define 1x1 mile. the earth is round, and the USA is big, and a 1x1 mile grid just doesn't fit unless you define some additional parameters. Maybe the best thing you can get is a coordinate list for PLSS sections. See Public Land Survey System for example.
posted by Chris4d at 10:27 AM on January 14