ES 551 Project

Bracey, Virginia, and Lake Gaston

Author: Steve Lowe

Date: May 03, 2002

Prepared for ES 551, Computer Mapping Systems, Emporia State University, spring semester, 2002

ES 551

The following map of Bracey, Virginia was produced from digital orthorectified quarter-quad aerial photographs obtained from Landinfo, Inc. and were originally published by the United States Geologic Survey. The software employed for the task was Idrisi32, published by Clark Labs, Inc., Hancom Painter, by Hancom, Inc., and Microsoft Paint.. Information regarding Bracey and Lake Gaston was obtained from the Lake Gaston Chamber of Commerce.

Lake Gaston Chamber of Commerce

The community was originally known as St. Tammany, after a 19th century ferry crossing on the Roanoke, and later became known as Bracey, after a prominent citizen in the 1930's. It is located in Mecklenburg County, just across the state line from North Carolina. The GPS coordinates are 36.6 N and 78.1 W.

Lake Gaston begins at Kerr Dam at Clarksville, built in 1953 for flood control. It covers over 20,000 acres, is 24 miles long, and has over 350 miles of shoreline. Because of its proximity to Raleigh, North Carolina and the Research Triangle, it has become a favorite weekend and vacation destination for North Carolinians and Virginians, and is the economic engine of its area.

One of the most popular recreational actvities on the lake is fishing. Striped and large-mouth bass, crappie, and several species of catfish are common, and yellow perch and walleye are occasionally caught. Other popular activities are boating, water-skiing, and swimming. There is virtually no pollution. The average summer temperature is 76.5 degrees F, and the average winter temperature is 42.4 degrees F.

The methodology employed to produce the map image involved use of the on-screen digitizing feature of Idrisi32. The quarter-quad aerial photographs of Bracey, United States Geologic Survey number 36078e2, were obtained in GeoTiff format on a CD from LandInfo. The import feature of Idrisi was then used to convert them to Idrisi raster format. Four layers, made from the northeast and northwest quarter-quads were digitized from the photos. Two shoreline vector layers, one from each quarter-quad were made, followed by two road vector layers, again one from each quarter-quad. The layers were combined with the add function. Finally a scale bar, north arrow, and titles were added to produce the map composition. A pale yellow was chosen as the background color for all map components.

Color was added to the water bodies by use of the paint features of the Hancom Office Suite and by Microsoft Paint. The shallower water effect was achieved with the water-color feature of Hancom Painter.

Additional text information indicating roads and water bodies was added with Microsoft Paint.

The following image is a Windows .bmp image of the northeast quarter-quad. As seen, the image should be useful for the production of very large scale maps. However, the problem of rendering a .bmp image from the map window of Idrisi32 presented a limitation on the achievable scale.