US National Grid – An Update


It’s been a while since we’ve discussed the US National Grid, but I was recently brought back to the topic.

Last week at work I got involved in a debate with some of our emergency response managers and operators on the issue of map grids. We are putting together a comprehensive emergency operations dashboard (web map) and I thought it would be useful to have a standard grid available that all agencies can use, understand and reference their response efforts against.

My first reaction was to just go ahead and use the US National Grid (USNG). It is easy for us to create web and paper maps that display the grid, it is easy to understand and its use is mandated by federal policy (or so I thought). I was quickly shot down. Someone in the ops group produced a PDF of a map displaying an arbitrary alphanumeric grid. This grid was generated a half decade ago by someone who is long gone and nobody knows where the CAD file is that holds the original grid drawing. Yet this grid has been ‘approved’ by a large federal agency with wide ranging authority and so it was deemed the grid for emergency responders to use. It didn’t seem to bother too many folks that the only place the grid existed was on this small scale PDF. No way to update the underlying map or photo, no way to bring this map into other products. It didn’t matter – this was the approved grid, period.

What really got my attention was when one of our emergency services coordinators, a good guy who’s had (by his estimate) hundreds of hours of federally mandated (and developed) training on disaster response, told me that in all his training classes he’d never even heard of the USNG.

Your tax dollars at work.

In the end we gave up and one of our sharp geospatial analysts was able to recreate the grid as a georeferenced polygon layer using the Data Driven Pages functionality in ArcGIS. So now this approved grid exists not as an overlay on a static paper product, but as a scalable data layer that can be easily incorporated into paper or web based map.

But still, USNG soldiers on. I snuck it in as a data layer in this operations dashboard. It’s turned off by default, but it’s there if needed. I guess everybody’s happy. The ops guys get their arbitrary grid that has no real relation to any recognized spatial coordinate system, but hell, it’s approved! I get a grid that may (or may not) be approved and mandated by the Feds, that every emergency responder gets schooled on when he/she goes for federally mandated training (or maybe not), and is supposed to be the standard emergency response grid system in use by the federal government (perhaps).

Again, your tax dollars at work.

In working through this issue and trying to find documentation and guidance on the mandated uses of USNG I happened on this interesting site, the US National Grid Information Center:

USNG Information Center

This site holds a lot of great information on the USNG and its applications, and I encourage everyone who deals with USNG or MGRS to spend some time going through the resources.

Even more interesting, it appears the site is not maintained or supported by any federal agency or the FGDC (the ‘father’ of the USNG concept). This is all a private effort and the site is supported by the SharedGeo organization.

So here’s an example of your tax dollars not at work, and it’s a good thing!

Brian

2 thoughts on “US National Grid – An Update

  1. Living in England where we have the Ordnance Survey grid system and a national mapping system in place since Napoleon threatened to invade, I was amazed to find that the same thing was not totally in place in the USA. Although most hand held GPS devices sold in the UK are set up to read latitude and longitude, with the exception of hardened geocachers most of us immediately reset them the UK OS grid system, a six figure grid ref defining a 100 meter square (More correctly two letters and six numbers). It’s logical and easy to teach and everyone who uses maps understands it, equally importantly everyone who produces maps for outdoor use uses it so it doesn’t matter if I am using a 1:25000 OS map and I am talking to someone using a 1:40000 Harvey’s map the grid system is the same. Obvious really.
    Regards
    Phil Ralph

    • Phil, thanks for the comment. Isn’t it amazing how an imminent invasion can spur standardization? Starting in the late 1940s the US military (and soon, NATO partners) we began ‘gridding the world’ with the Military Grid Reference System (MGRS), but the US military was prohibited from producing maps over the US (except for our Federal military installations and training areas), and the US Geological Survey was content to stick with UTM and Lat/Long (and Township and Range!)for our national mapping program. This issue finally got serious attention during the recovery efforts for Hurricane Katrina in 2005 (which devastated an area larger than England) when the various response agencies – FEMA, the US military, Red Cross, Homeland Security and our local and state agencies – could not pass location information in the same map ‘language’. The US Geological Survey finally agreed to add the USNG to the new US Topo map series. But still, its adoption continues to be slow (and there’s another blog post coming on that topic).

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