by Lorien Nettleton ~ April 18th, 2012
For many Alaskans, any vacation planning starts with clearing room on the kitchen table and unrolling a map. Many of these maps have been made by the United States Geological Survey. The USGS has been the authoritative mapping organization for the united states government for 132 years. In the 1990s they completed a 50-year effort to map the entire United States. Now the USGS is on the verge of completing a total re-mapping of the united states, and the results will be digitally available online.
The new map product is called US TOPO, the maps will be available digitally, and will include areal imagery, topographic information, hydrography of rivers, lakes, streams and swamps, and transportation networks. In the last 3 years the USGS has completed 54,000 of the revolutionary maps for the Lower 48. But mapping Alaska has always been faced with a different set of circumstances. Early efforts to map the vast Alaskan unknown were undertaken by a handful of scientists trekking across uncharted territory. Mark DeMulder is the director of the USGS’s Geospatial Program, and he is well acquainted with the early 20th century’s era of exploration.
DeMulder has been overseeing the US Topo project since its inception in 2009, and Alaska is the final piece of the puzzle. For the first time since the middle of the last century, a total re-mapping of the state is now underway. DeMulder says the transformation in technology will result in the most detailed, accurate statewide topo maps we’ve ever seen.
For the rest of the country, map scales have been 1:24,000, or one inch to 2000 feet. Because of its remoteness and the difficulty of obtaining geographical information, Alaska was mapped on a different scale of 1:63,360, or one inch to a mile – roughly half the resolution for the rest of the united states. When the new US TOPO maps of Alaska are released, they will have the same higher resolution of 1:24000 as the rest of the country.
The biggest thing that has changed is the technology. The current mapping effort is done entirely by airplane, using a kind of radar called IFSAR, which stands for Interferrometric Synthetic Aperture Radar. It uses a precise aircraft-mounted radar system to bounce a signal to earth, measuring the time for that signal to return. The result is highly accurate elevation data that can be collected from large areas at a time. And, in another break with mapping challenges of the past, DeMulder says mapping with IFSAR isn’t restricted by seasonal weather obstacles.
So far, elevation data has been collected for a little less than 20% of the state. When the rest of the IFSAR Data has been mapped and the quality checks completed, the new maps will be released digitally in a format called GeoPDF, or a PDF with geo-notation. While many topographic products are on the market, DeMulder says GeoPDFS are revolutionary in that there is no additional software or expertise needed to use them.
DeMulder says that part of what makes mapping Alaska so challenging, is that much of the information has never been collected before.
The work of actually mapping the state will conclude this year, and after quality checks are conducted, the final product could be in production by 2013.
In addition to the remapping effort, the USGS is completing a project to release every map they have ever made in the same Geo PDF Format. DeMulder says this feature has quickly become very popular with the public, and has broad applications for a variety of uses.
So far 160,000 historic maps have been made available, and with 20,000 left to digitize and correct for scale, all existing historic maps of Alaska will be available online for free by September.