| In Living Color: USGS Paper Maps Go Digital
Off-the-shelf digital basemaps provide attractive alternatives to USGS topographic quad sheets.
By Mary Jo Wagner Ed Northrop doesn't mix words. "We live and die by the USGS quad sheet. Without it we'd be up a creek," he says.
Northrop, manager of surveying and CAD at National Fuel in Erie, Pa., is referring to the 7.5 minute topographic paper maps that the U.S. Geological Survey produces.
Natural gas companies such as National Fuel, as well as oil and petroleum companies, need USGS quad sheets to make any move. All permitting for exploration projects, routing pipelines, locating wells and access roads are done on the basis of quad sheets. They are a daily part of life.
To the USGS' credit, the topographic maps they create are very good, and have an accuracy of plus or minus 40 feet, says Northrop. They are produced at a standard scale of 1:24,000 which is also the standard scale requirement for the oil and gas industry.
The USGS quad sheets have been a sufficient mapping resource but intensive labor and expense have come with managing paper maps.
Changes to previous project plans would make for many sweat-soaked shirts at National Fuel or any other company in the industry. Editions with a paper map is a laborious job as new quad sheets have to be ordered and new maps created by hand.
If projects require a larger scale, using the paper maps doesn't allow you to change the scale. Any additional information or features needed on the maps must be penned by hand. And large projects that require multiple maps to cover the entire site prove difficult as the maps have to be manually cut and pasted together.
Michael Blakeman is committed to taking that paper world and converting it to digital basemaps.
Blakeman is the president of Land Info, located in Denver, Colo. A mapping data product company he started in 1992, Land Info produces digital raster maps of USGS 7.5' topographic quad sheets in color.
Each map is color scanned and georeferenced by using 16 control points, meaning each pixel is assigned a coordinate value. The maps are stored in a TIFF format in a databank and are available off-the-shelf to clients.
By georeferencing each map, Land Info has been able to create a "seamless" database. No longer are map margins or map collars visible between maps. Maps are strung together in a continuous display of map images. Clients have infinite options for choosing their map area as any geographical location can be produced. Blakeman refers to this as "cookie-cutting" out an area.
"We can fulfill your orders by your geographical area of interest," says Blakeman. "You can have one map or the entire U.S. You can have maps of just a forest, a park, a county or a city, or maps that follow a corridor for a pipeline, or a highway."
Land Info raster maps are compatible with most GIS and image processing software, says Blakeman. Through the software, the users can perform many functions, such as altering the physical look of the map and changing the 1:24,000 scale to fit their needs. The company also has the technical capacity to project the maps to any particular coordinate system.
"Each map has a high-quality resolution," explains Blakeman. "This gives clients both the ability to zoom in and look at one square inch without distortion and to plot high- quality maps."
Land Info produces a map only once. Enhancements can be made to the map but the basemap for any given geographical area will be an original. Because Land Info can resell each map, they can offer their maps at a lower cost than most other mapping services, says Blakeman.
"The service bureaus charge an exorbitant rate to create vector files and they produce the same map repeatedly," he says. "I saw the need to create a databank of information that had marketability, universal compatibility with GIS software, was affordable and that clients could get off the shelf."
In turn, clients can use their raster maps repeatedly for various projects, reducing their overall costs of doing business.
To date, Land Info possesses 57,000 maps, covering the entire U.S., and a long client list.
Wolverine Gas and Oil Company in Michigan is one of them. Mark Lutz, a cartographer at Wolverine, says the raster image maps from Land Info have been a useful aid for their work with Antrim play and for shooting seismic lines.
"Before Land Info it was more a cut and paste operation," he says. "If we identified an area that might encompass four quad sheets, we would have to make copies of those four and cut them together and do all our work on that kind of basemap. Now we've got the seamless quad sheet in the system as an underlayed basemap."
Producing the maps in color is important because it provides users with a visual reference guide, says Blakeman. Color-coded features of particular importance can be highlighted or even isolated to create a feature-specific map.
"Many people, including ourselves, want to see the contour information on a USGS topo, but they don't want to pay the expense to have them digitized in vector format," Lutz says. "With these products, you can turn off all the colors on the raster sheet so that just the contour lines remain because they have a unique color."
In contrast, colors can also be removed. For example, Lutz says that in his work, the green of woodland is a distraction and creates a noisy basemap. As each map file contains a color palette, the RGB values for green can be altered to remove it from the map completely.
Another benefit of raster maps, says Northrop, is the ability to make multiple copies of the maps.
Many government permitting agencies require the original quad sheet. Depending on how large the project is, or how many permits are needed, it can be very labor intensive to pen each map by hand.
Northrop uses one of the largest projects National Fuel has ever undertaken as an example. "For that project we will have to produce 100 sets of quad sheets for the Federal Energy Regulatory Commission and interveners. Thirteen quad sheets make up one set and we need 100 sets of original quad sheets. Could you imagine inking 1,300 quad sheets by hand?"
Any changes can be handled quite easily with digital maps, saving companies substantial time and money.
"With routing and laying pipeline projects, there are continual changes until the pipes are actually placed in the ground," says Northrop. "With a paper map, if there is any relocation or design change in the original route, you have to get more maps, plot the new route and send them out again. But with raster maps, you can make the changes with a few keystrokes. And we can electronically send that map to whoever needs it in real-time."
Expelling the need to manually piece separate paper quad sheets together allows users to work more efficiently and effectively. "We were just in the process of building a 16-mile pipeline at a scale of 1:500," says Lutz.
"We were able to put together six map sheets that covered that 16-mile stretch in about a day and a half."
The engineer responsible for producing those basemaps for the project commented to Lutz that it normally would have taken him at least a week to create those maps using traditional map-making methods.
As Land Info can supply maps in any coordinate system a user specifies, overlaying supplemental data is easier, says Tim Driscoll, cartographic technician at National Fuel.
"The ability for Land Info to provide different coordinate systems is important because our operating area encompasses four different state plane coordinate systems," he says. "When we collect GPS data in one of those four state plane systems, the data overlays exactly where it should, which is pretty amazing."
Ground surveys to verify the accuracy of the maps are not necessary, they say, but because Land Info maps can only be as recent as the latest published USGS quad sheet, sometimes features will appear which are not on the original maps. Upon inspection of an area of interest, these features can be added to the digital maps.
"Depending on your area, the quads may not be updated frequently so many times there is a new road that's been constructed that won't show up on the quads," says Mike Tarr, survey engineer at National Fuel. "I can map it with the GPS and overlay it on the raster quad. It fits very nicely."
Features and symbols particular to the oil and gas industry can also be inserted to maximize the maps informative value. For instance, well locations and their status can be indicated with symbols signifying a dry, abandoned, plugged or active well. Shot points and production leases can also be overlayed.
All those interviewed say the fact that Land Info maps are seamless, georeferenced datasets is of great benefit to their work, making practically every aspect of their activities easier.
"The maps have been a very useful tool," says Lutz. "I know when our maps get out in the field and are seen by other companies they say, 'Wow, how did you do this?' So more people are becoming aware of the raster-vector compatibility."
In Blakeman's opinion, one of the greatest benefits of these maps is the ability to create hard copy color plots, for both internal and external use.
"The maps provide a general reference basemap at an ideal scale," he says. "Clients in the oil and gas industry won't rely on our maps to drill a well, but they'll rely on our maps to explore for oil and determine a location.
"They're able to bring all the maps together in the computer in a seamless form and then plot their particular play," he continues. "And everybody involved in the project will look at one common map that applies to all areas within that exploration process, at one scale that is sufficient for everyone."
Land Info's raster maps are a useful GIS tool, providing accurate and quality basemaps upon which to overlay both general and detailed information and geocoded features, says Blakeman. Quality basemaps will help users get results.
"I really want to emphasize that quality data is the ultimate solution," he says. "Data available to the industry in an off-the-shelf approach is what I'm really trying to promote. I think that if data is not created to meet the universal needs of any industry using GIS, and is not readily available, that's going to impede the future productivity of GIS."
Adds Northrop, "You don't have to be running a GIS to benefit from these maps. Anyone doing construction, engineering, oil, gas, geology, forestry or environmental work, could benefit greatly by having maps in digital format."
Off-the-shelf Land Info raster maps can reach a client as quickly as the postal service can deliver them; USGS quad paper sheets can take from four to six weeks to arrive.
And as Land Info has already covered the U.S. the next logical step for Blakeman was to go abroad, scanning and distributing maps of South America, Russia, the Far East, the Middle East and Canada at 1:50,000 scale.
The international market holds enormous natural resource exploration potential and has the attention of many major U.S. oil and gas companies. Much activity is already going on. And Blakeman predicts more to come. About the Author:
Mary Jo Wagner is a freelance writer/editor who writes about GIS and remote sensing. She may be reached at 415-291-8292. Back |
