The US Geological Survey is responsible for accurately charting America’s ever-changing topography — including the streets (and cities) that come and go. The Chief of the Western Mapping Center talks about what it takes to do this work, and the resources the USGS offers to teachers.
What does your organization do?
The USGS is responsible for mapping and providing the maps of the United States of America. My center is responsible for mapping the nine western states.
Our division is one of four scientific divisions. The other three are: the geologic division that works to understand the structure of the earth and the process of earthquakes; the biologic division, which studies the biological resources of the nation; and the water resources division, which studies the quantity and quality of the nation’s water.
We do extensive scientific research and operations to support the nation’s decisions regarding natural resources.
Haven’t we discovered and mapped everything?
The USGS maps have a specific scale: one inch equals 2,000 feet. Each map is equivalent to a piece of earth that is seven and a half minutes of latitude by seven and half minutes longitude.
We completed that mapping for the first time in 1990. But, like most nations, we change and we grow. There are new roads. Some roads have been taken out. Cities are being built. The Earth’s surface changes. So it is an ongoing process — we are continually trying to keep up with the changes that are happening. It’s quite a challenge, as you might imagine.
We work a lot with the private sector and other agencies. Our resources are quite limited, but through partnerships with the state governments, county governments, and city governments, we’re able to build a national database and map the information in paper and digital form.
Are these maps available to anyone?
Yes they are; the maps were produced with the use of a public fund so they are public information. You can go to the USGS web site* to find a specific map — there are small charges to recover the costs of distribution and processing.
How is mapping done these days?
About 20 years ago, most of the work was done using photographs taken from airplanes flying in the ten or twenty thousand foot altitude range. This information was checked in the field by surveyors.
This process was very expensive and very time consuming. Today, we rely on computers and computerized imagery and information from satellites.
Satellite images are getting really good now, but they have not yet replaced our mapping program. The resolution and accuracy of this data is not quite up to the levels that we have been accustomed to in making the first time coverage.
What sort of math and science skills do you use as a cartographer?
Photogrammetry — a big word in our profession, which means making measurements from photos — depends on trigonometry and geometry. We rely on the visual relationships, the angles and lines and distances.
As we get into mapping from satellites, the higher levels of math, like calculus, are needed to understand the orbital dynamics of satellites, how images are manipulated and things like that.
What’s the difference between cartography and photogrammetry?
Photogrammetry is a science that is also kind of an art. It makes it possible to acquire and make measurements from photographs.
What a cartographer does is make a map by converting this mathematical output into lines that represent features on the ground.
What kinds of training do people need to do this work?
We draw on many different disciplines. My background is civil engineering, with the option of surveying and mapping. We have a number of physical scientists, and computer scientists, clearly, because of the need of our automatic data processing.
We are getting into some projects that involve additional disciplines because of the applications of the map information, so we also have geologists, and hydrologists and biologists working with us.
Are there many opportunities to work in this field?
One of our researchers did a study, and estimated that about $3 billion of the gross national product is based in some way on geographic and geospatial information. This spans everything from where a Sears Roebuck is going to open their newest store, based on the demographics and the traffic patterns, to information gathered by Federal Express and UPS to expedite delivery.
I think if you named any profession or business you might find some linkage to geographic information. If a young person is interested in any way in a profession that involved using maps and map information, they could find a pretty good job.
What are some of the things you offer to educators?
We have assembled a number of educational, informational pamphlets and booklets on the various disciplines at USGS.* We’ve got teacher packages for mapping and geology and for water resources, and biology as well. We also have general information publications geared for the entire span of educators, from students all the way to the users of our products and services.
Do you think in another few years you’re going to be busy mapping Mars?
I would hope so! Actually, the National Aeronautics and Space Administration will probably be the principal investigator in that study, but I am hoping they will come to the USGS to employ some of our work force to help them out.
*USGS Resources for Teachers and Students