Wednesday, April 23, 2014
By BETTY ADAMS Kennebec Journal
Orthoimagery gives a really close look at the face of the Earth and true distances between points.
Portland Head Light in Cape Elizabeth is depicted in orthoimagery from a flight in spring 2012.
Image courtesy Maine Geolibrary Orthoimagery Program
LEARN MORE ONLINE
INFORMATION about the project is available on the website of the Maine Geolibrary at www.maine.gov/geolib.
It shows striations in the rocks forming the breakwater around Portland Head Light and the shadows of the visitors walking on the lighthouse grounds. The same 3-inch resolution -- the best available -- shows individual rows of seats at Hadlock Field in Portland.
While the low-flying bird's-eye view fascinates, it can be even more important economically to transportation planners, utility districts, surveyors, foresters and developers.
That is the point being emphasized to counties and towns in central and coastal Maine by promoters of the Maine Geolibrary Orthoimagery Program, which is looking at updating images of the entire state.
The focus now is on Androscoggin, Kennebec, Knox, Lincoln and Sagadahoc counties. Last year it was on Cumberland and York counties, and almost all the larger cities bought in, as well as the coastal communities, said Joseph Young, mapping coordinator with the Department of Agriculture, Conservation and Forestry's Floodplain Management Program.
"Kennebec County is buying in, so all the towns in Kennebec get a 2-foot resolution image and they can individually upgrade to a higher resolution," said Robert Devlin, Kennebec County administrator. "By us participating, it significantly reduces the cost to the towns."
Fayette selectmen will hold a public hearing on their proposed purchase of 6-inch resolution imagery for $10,500 during the regular 7 p.m. meeting Monday at Starling Hall.
The Maine Geolibrary Orthoimagery Program calls for mapping the entire state in a counterclockwise circle beginning at the southern end.
"It's done by a plane flying at about 3,000 feet," Young said, although the altitude varies according to the resolution sought.
He refers to 3-meter resolution as coarse and something that can be taken from 10,000 feet.
"Portland purchased 3-inch imagery -- very high resolution, very accurate," Young said, and requiring a lower altitude. "Six-inch resolution gives a very clear resolution of decks and buildings, so when you're doing jobs as assessors or code enforcement officers, it helps both towns and the property owners."
Peter Crichton, manager of Cumberland County, which participated last year, said the project was well worth doing.
"I've only had positive comments about the work that has been done. The thing that really intrigued me was the partnership with federal, state and local governments, with counties being able to provide funding," Crichton said. "We enabled a lot of municipalities to have access to GIS that otherwise would not have been able to afford it."
Kennebec Journal Staff Writer Betty Adams can be contacted at 621-5631 or at: