Above: The deputy director says that NGA wants to have a bigger role.
Editor’s Note: On July 23, xyHt editors Gavin Schrock and Dave Doyle were invited to address an audience of professionals at the headquarters of the federal government’s National Geospatial-Intelligence Agency (NGA) in Springfield, Virginia.While this was a closed-door session held to help NGA staff learn about a variety of subjects in the world of our readers, both editors felt that this meeting, along with xyHt being invited to interview the deputy director of NGA days earlier (see the video on our website) represents an effort by the normally secretive defense and intelligence agency to engage more openly with the private sector.
Because I didn’t know what this meeting was going to be about, I envisioned that it was like an opening to xyHt magazine and its readers to create a working relationship between our world and NGA, which is a very secretive kind of organization. They keep a lot of things very close because that’s just the nature of the intelligence business. So I thought that opening up a few lines of communication on technological advances that the magazine [is interested in]—whatever comes out of this—can only be a good thing.
The audience we spoke with at NGA was mostly surveying and other mapping and charting types.
They wanted to know about things like the relationship of World Geodetic System of 1984 (WGS 84), the positioning system for the Global Positioning System (GPS), and how that compares to the national geometric datum for the United States, the North American Datum of 1983 (NAD83). And about gravity data for heights, like Gravity for the Redefinition for the American Vertical Datum (GRAV-D), which the National Geodetic Survey (NGS) is working on.
I think they are interested in educating their own people about the conditions that exist in surveying and mapping in the country because a lot of their folks—since they are totally focused on the military and intelligence side of the equation—deal very, very little with the real practical side, the commercial side, things like the relationship between WGS 84 to NAD 83.
They don’t have to worry about things like that because they are not involved with local surveyors or people who are building a GIS for a local government—that is not their world. They define and maintain WGS 84 because that is what they need to do for the GPS constellation and to support their mission, and if someone wants to go use it for something else, that’s up to them.
But, I sense there’s a kind of new environment that’s evolving over there: that they’d like to be a bit more open, that they would like to be able to share more of what they have with the civilian side of the equation. I think this could be a really big thing for our readers.
First of all, there are a lot of people who don’t even know what NGA is. While NGS is pretty well known to the surveying community, NGA, which has responsibility for maintaining the coordinate system for GPS, is probably only known by a handful of the tens of thousands of surveyors in the U.S.
NGA collects not mountains of data; they collect universes of high-quality geospatial data, because everything is about place, and they understand that. They are using technologies that are either in the public domain or are being developed and will be in the public domain.
It’s not like it was 45 years ago in 1970, when I got out of the service. There was a real distinction between remote-sensed data that the military got versus what the civilian community got. I’m sure that [distinction is] almost completely gone. I’m sure they can get some data that’s better than what’s commercially available, but not a lot because the commercial side has made such monumental advances.
So, in many cases NGA and other parts of the intelligence and military community are using commercial products and maybe tweaking them for their own issues. Again, since it’s all classified we have very little knowledge of that. But now the technology is not so different.
This meeting closely followed NGA agreeing to allow us to interview their deputy director at the Esri UC in San Diego, in which she had told xyHt that NGA wanted to have a bigger role. But what does that mean? What can they offer that will be meaningful to a multitude of different disciplines?
I think that part of this might have been just scratching that first surface to find out some of the areas that we can collaborate on between the private and the public sector. But also the intelligence sector.
At the meeting I was pretty upfront in that there were a couple of things I indicated that I thought they should do.
With regards to WGS 84, they’ve done a great job. They developed the coordinates system for GPS, and they maintain it. They’ve always had that responsibility, going back to 1987 when it was first released. They just released a brand-new publication last July about WGS 84 working from their geodesy side, but almost nobody knows about it.
Setting the Record Straight on WGS 84 ≠ NAD 83
The most misunderstood aspect here shows up when I travel around the country and speak to a variety of groups. You still hear a very common statement that WGS 84 (the coordinate system for GPS) and NAD 83 are the same. There are two reasons for that.
Math transformation
One is that in this publication that NGA has produced, there is a mathematical transformation to go from one to the other. Without getting too far down the technical rabbit hole here, the transformation is zero. So if I have a number over here and add zero to it, I get the same number. You don’t need to be Stephen Hawking to figure this one out. And those transformations are embedded in every GPS receiver in the world and all the GIS software, Esri and all the others included.
But in the publication, right next to those zeros, is the standard deviation of that number, which is plus or minus two meters, and no one ever sees that. All the user ever sees is the zero. They go to this box and they say, “I am collecting data from GPS and I want to get it NAD 83, and I punch this button, and the same number comes out.” So, therefore, the conclusion is that they are the same, but they are not because the standard deviation is two meters and it’s in the book, but it never gets brought over into the software. And if you don’t have the book you don’t know about it. And NGA never really publicizes that.
Today, there are more sophisticated and accurate transformations, like the NGS tool Horizontal Time Dependent Positioning (HTDP), and NGA has it in their document but they don’t market it. No one knows about this document.
Nautical and aeronautical charting
The other reason people largely think they are the same is that in 1995 the federal government’s Federal Geodetic Control Subcommittee (FGCS) issued a Federal Register notice that says NAD 83 and WGS 84 can be considered the same for mapping and charting purposes at scales of 1 to 5,000 or smaller. So, it’s aimed at nautical and aeronautical charting. You don’t want to have mariners or airline pilots going, “Oh, I have a different datum here; my GPS says one thing and my chart from Dulles says another.” For their world, two meters, you’d never see it on a chart.
But for our world, the positioning world, is very different. Especially now, when here we are 30+ years from the development of GPS, the needs of the user community has gone so far beyond what it was 30 years ago. Back then, two meters was good enough. Who cared about two meters 30 years ago? Just this handful of surveyors and geodesists, and a few engineers and geophysicists. Well, now everyone and their brother are demanding a couple of centimeter accuracy from this multitude of platforms that we talk about regularly in xyHt magazine.
I don’t care what it is, whether it’s hydro or it’s the cell phone, everyone is demanding and getting what they want, and now this level of accuracy means something. So, today, it is a matter of getting this information out there to this hugely expanding network of users of the multitudes of sensors that we all see and that we talk about regularly in xyHt. [We’re] getting everyone to understand that these are not the same. Now you are going to have conflicting data that can easily be at the range of a meter or two, and how do we resolve that?
Looking forward to 2022, NGS has talked about this in the FCGS meetings that are held periodically, and NGA is supposed to have a representative there. I don’t know how much of the information gets communicated and trickles down to the multitudes of users that they have, but I suspect it’s not very good. This is not just NGA; it’s almost every federal agency that I’ve ever dealt with.
Sharing Data Products
Over the past 15 or 20 years, NGS has had a pretty good working relationship with NGA and its predecessors, mostly on the gravity side. So, if you were to go to NGS and talk to any of the guys who work on the gravity side and say, “What do you know about NGA,” they’d be, “Oh, we’re sharing gravity data with them back and forth, with limitations.” NGA will share data with certain limitations, as NGS gets the data and uses it as part of the development of geoid models, but beyond that there has been little connection with NGA.
I think that if our audience with xyHt knew more about the data products that NGA had that could be open to the public, then a greater dialog could be created. This is where I believe NGA has to step up and say, “We want to be more transparent.” Otherwise we don’t know what they have. They are a huge agency with massive amounts of data, so where do you even begin?
I think they have to create that side of the dialog to say, “These are the kinds of data we have—whether it’s hydro data or aeronautical data or conventional lidar—these are the kinds of data that we hold, and we can find a way to share it with the public.”
How that data gets organized and distributed: I think once the public knows what they have, then they can create an environment and say these are the kinds of data products we need. It needs to be a two-way street.
To make this opening between our communities meaningful, I think something needs to happen at a pretty high level at NGA. My sense is that the worker bees [at NGA] are pretty compartmentalized; they don’t necessarily know what anyone else is doing, unlike at an agency like NGS where everyone sits down, is integrated with the nautical side, the tides side, et cetera. Even if people don’t take advantage of that knowledge, it’s there.
I can see where NGA is coming from if you look back at the history of NGA and its predecessors: the Army Map Service (AMS), the Defense Mapping Agency (DMA), the National Imagery and Mapping Agency (NIMA): they have a very long and proud surveying, geodesy, mapping history. They had some folks over there who were truly monumental in these fields. But over the years, that side of the equation has been pushed further down the food chain as they’ve added more to the intelligence pieces.
So there is the geospatial part of it, which is obviously much bigger and has a much broader context, but they don’t stand alone like they use to as DMA It’s now the National Geospatial-Intelligence Agency. Well guess what: the “I” part of that is way bigger than the mapping side.
One of things that NGA staff, one man who leads the hydro section, said: that this week or next week they were going to have a meeting with a few folks from NOS [National Ocean Service]. I suggested that they try to figure out if there are meaningful ways the two organizations can create products and services, because you’ve got geodesy going on at NGA and geodesy obviously going on at NGS.
Well. NGS has this wonderful tool kit that surveyors and others can come to and use the products and services. How can that be expanded to include some elements of whatever NGA has? Is there a mechanism to make that happen? I’d suggest using that already-existing federal environment and say, “Here’s this tool kit; let’s get some technical people to sit down and figure out what it is NGA can contribute to it.”
I do think that ultimately there needs to be something coming from the top at NGA down, such as saying, “Here are data that is absolutely classified, we can’t share this with anybody. And here’s some data that is not classified, and we can share this with you.”
Why is this occurring now, I have little idea. Perhaps that unlike in the old days when it was AMS or DMA, and the defense side had its own geodetic and mapping authorities who did all their work, they rarely went out to contractors to gather this data. That’s not the case anymore.
While the military maintains some level of that, they have a lot of contractors, and those contractors don’t know stuff. They would come to us at NGS and say, “I’ve got this contract working for this Air Force base; what do I do?” I see a need for standard operating procedures that are online. If somebody is going to work for you, you can tell them, “Go to this page, and here’s the list a, b, c, d to z. These are the things that need to come back from a survey like this, that everybody can see and understand.” That kind of guidance doesn’t exist. And every contract is a little bit different.
So, there are lots of things that are opening up here, or at least people are realizing that we need to find a better way to do this.