US Geological Survey
The USGS is a science organization that provides impartial information on the health of our ecosystems and environment, the natural hazards that threaten us, the natural resources we rely on, the impacts of climate and land-use change, and the core science systems that help us provide timely, relevant, and useable information. http://www.usgs.gov/
1 dataset
Topographic Change in Philadelphia
A scope of work was developed in response to a request by the U.S. Army Corps of Engineers, Philadelphia District. The request was to perform a topographic change grid analysis for the Frankford 7.5-minute quadrangle, 1:24,000-scale topographic map, which includes the Wissinoming neighborhood, and the Germantown 7.5-minute quadrangle, which includes the Logan and Feltonville neighborhoods of the City of Philadelphia. The following tasks were performed under this scope of work: A GPS-corrected GIS grid analysis for each quadrangle was completed and is accompanied by documentation that describes procedures and provides metadata of the informational content of the GIS. A high-resolution global positioning system (GPS) survey was conducted for each topographic quadrangle in order to evaluate and correct systematic discrepancies in elevation between the modern and historic surveys. Prior to release, the fully documented GPS-corrected GIS grid analysis for each quadrangle was reviewed for (1) com-pleteness of documentation and for (2) appropriate analysis and discussion of uncertainties. The following report is in fulfillment of the tasks outlined in this scope of work and was performed by the U. S. Geological Survey for the U. S. Army Corps of Engineers, Philadelphia District under MIPR agreement number: W25PHS93358288.