What is USGS map?
The National Map is a suite of products and services that provide access to base geospatial information to describe the landscape of the United States and its territories. The National Map is easily accessible for display on the Web through such products as topographic maps and services and as downloadable data.
How accurate are topographic maps?
Turns out, USGS topo maps use the National Map Accuracy Standards. This means that 90 percent of the horizontal points tested by field survey teams are accurate to within 40 feet. Vertical points, to within half a contour line, or five feet, based on standard 7.5 minute, 10-foot contour lines. So, yeah.
Are GIS maps accurate?
GIS data is pulled together from a variety of sources with varying degrees of accuracy and precision. Therefore, overlaying a parcel database that may have an accuracy of +/- 10 feet onto aerial imagery with an accuracy of +/- 30 feet can lead to features ending up over 80 feet away from their true point.
What is a 7.5 Quadrangle map?
A “quadrangle” is a topographic map produced by the United States Geological Survey (USGS) covering the United States. A 7.5 minute quadrangle map covers an area of 49 to 70 square miles (130 to 180 km2).
Are the USGS topo maps public domain?
All topographic maps produced by the U.S. Geological Survey (USGS) are in the public domain and are not copyrighted except for the following three cases that apply only to US Topo maps (produced 2009-present):
What is an USGS topographic quadrangle map?
The U.S. Geological Survey (USGS) publishes maps at various scales. The scale used for most U.S. topographic mapping is 1:24,000. USGS maps at this scale cover an area measuring 7.5 minutes of latitude and 7.5 minutes of longitude and are commonly called 7.5- minute quadrangle maps.
How are U.S. Geological Survey topographic maps named?
S. Geological Survey topographic maps named? A USGS topographic map is usually named for the most prominent feature within the bounds of the map, which is frequently a community. Most topographic maps are named for the most centrally located, well-known, and/or largest community identified on the map.
What is a geological survey marker?
Survey markers, also called survey marks, survey monuments, survey benchmarks or geodetic marks, are objects placed to mark key survey points on the Earth’s surface. They are used in geodetic and land surveying.