APPENDIX E 

Spatial Interoperability 

In the specific case of air-delivered weapon support to ground forces, the precision bombing 

benefits of the common-grid capability afforded by GPS cannot be assumed in advance. To 

ensure GPS common-grid is applied in air-delivered weapons support, a change in joint doctrine 

is necessary to require in-theater use of the grid reference alphanumeric position reporting 

system, Military Grid Reference System (MGRS), for all 2-D positioning, navigation and 

targeting purposes and as the 2-D component of 3-D operations. Universal use of the MGRS for 

all in-theater spatial operations will eliminate confusion regarding which coordinate system is 

being used in navigating and reporting positions and targets. It will also eliminate the practice of 

requiring that ground personnel electronically or manually convert positions and targets from 

MGRS to latitude and longitude for the purpose of obtaining support from aviation components. 

In any emergency situation, whether in a war zone or the domestic environment, spatial 

interoperability is as important as communications interoperability. Said another way, confusion 

in identifying an incident location can be as deadly as not being able to transmit that location to a 

potential responder. GPS can solve that problem, but only if it is employed smartly and with 

forethought. GPS enables common grid operations, but only if the participants agree in advance 

on which of the many available coordinate grids they will use to identify locations of importance 

to the operations. Coordinate grids are the languages of location, and using different grids in the 

same operation is analogous to trying to communicate in different languages. 

Military Spatial Interoperability 

In the military mission environment, spatial confusion in joint operations can result from 

different participants in an operation expressing locations using spherical geographic coordinates 

(latitude and longitude - lat/lon) and planar grid coordinates (Military Grid Reference System). 

There are good reasons for using each, primarily related to distances traveled, but from a spatial 

interoperability standpoint this is like discussing ground operations in English and airborne 

operations in Chinese. When the two have to work together, translation is critical, but under 

stress, mistakes are all too common. The burden of conversion routinely falls on the ground 

troops, who are likely already over tasked in a stressful environment, many times under enemy 

fire. This is the reason for the recommended revision to joint operational doctrine expressed in 

the Weapons Delivery section above. 

Civil/Homeland Security Spatial Operations 

In the civil environment, people today have great difficulty in finding map products (even those 

provided by digital sources) which contain grids that can be used with GPS equipment. Those 

map products that do include grids may use any of several grid systems to identify locations, a 

Excerpt from Report of the Defense Science Board 

Task Force on the Future of the Global Positioning System, 

October 2005 
 

Excerpt from Report of the Defense Science Board 

Task Force on the Future of the Global Positioning System, 

October 2005 

lack of standardization that can create time-consuming confusion in time of emergency. Many 

of the commercial proprietary grids do not permit precise locations to be determined, and 

virtually none work with GPS equipment. However, in a December 2001 action to address 

Homeland Security issues, the U.S. Federal Geographic Data Committee approved a new 

standard grid for such applications that can eliminate this spatial confusion. Called the U.S. 

National Grid (USNG), this standard will permit easy depiction of positions to 10 meters or less 

anywhere in the United States using an alphanumeric designator about the size of a telephone 

number. The USNG is based on the global standard grid called Universal Transverse Mercator, 

so it is non-proprietary and globally extendable. It is also designed to be identical to the MGRS 

grid coordinate system used by the Army and Marine Corps, so it can directly enable spatial 

uniformity in joint civil-military response operations. 

Lack of a uniform method for describing incident locations has long been a major impediment to 

rapid and effective emergency response in diverse metropolitan and rural areas. Until the 

adoption of the USNG, there has been no standard that would enable uniform large-scale map 

products to be created that could be used directly with GPS equipment and be applicable across 

jurisdictional boundaries nationwide. The USNG corrects that glaring discrepancy, but, having 

now been officially adopted, it still must be used to be effective. A program of education and 

training, beginning at the middle school level, would be instrumental in facilitating its use by the 

public. More focused leadership by the Federal Government to promote such basic education as 

well as training in the uniform application of GPS at federal, State and local levels by emergency 

responders would pay nationwide dividends for Homeland Security. 

The immediate domestic impact of USNG will be to ensure that GPS is directly useable with 

properly gridded map products to quickly enable multi-agency and multi-jurisdictional 

emergency responders, and the public in general, to precisely identify geolocations in the real 

world. Linking current technologies of overhead imagery and Nationwide Differential GPS at 

one-meter accuracy, the USNG can facilitate direct creation of gridded, very precise, large-scale 

image maps that would be immediately useable with GPS receivers. These maps will be 

extremely useful to emergency responders as they will depict the emergency environment as it 

exists rather than as it previously appeared from potentially out-of-date legacy sources. GPS 

commercial receiver manufacturers are now beginning to include the USNG in their newest 

products. As awareness of its usefulness grows, prompted by education, the USNG will be a 

principal integrating mechanism to create spatial interoperability nationwide. It will be equally 

effective among multi-jurisdictional civil emergency response organizations and, when 

necessary, between those organizations and the military to support any and all domestic 

emergency response and disaster relief operations.