US Topo - 3 of 29
US Topo FAQs - 29 Found
The new topo maps aren't as good as the old maps!? The new ones don't have xxxx....
Traditional national mapping programs gathered data from primary sources, including direct field observation. Such maps were compiled, drawn, and edited by hand. In the United States, the era of traditional topographic mapping lasted from about 1880 to about 1990, and was primarily the responsibility of the U.S. Geological Survey (USGS). By today's standards these traditional methods were very expensive, and USGS no longer has either mission or funding to make maps this way.
A new USGS topographic map series was launched in 2009 and branded "US Topo." Though designed to look like traditional 7.5-minute topographic maps, US Topo maps are mass produced from secondary sources, primarily The National Map and other government GIS databases. US Topo maps are a repackaging of GIS data in traditional map form for the benefit of non-specialist map users. Some of the layers in this map series come from non-USGS sources, primarily agencies that have data authority granted by OMB Circular A-16 (see links below), or land management agencies, or in some cases even non-government organizations. US Topo maps reflect both the strengths and weaknesses of current GIS datasets. At this time, GIS datasets typically lack some feature types that would be captured by traditional field work, and different classes of GIS data are usually not as integrated as the output of manual compilation methods.
The most obvious weaknesses of US Topo maps are related to lack of data, but there are also software and processing issues. There are some things, such as map text placement, that computers still don't do as well as humans, especially when the source GIS data are not designed to support this use. However, the US Topo project has made steady progress on solving both problems, as can be seen by comparing US Topo maps published in 2010 with those being published now. We believe that general-purpose topographic maps produced from GIS data and with automated methods can eventually approach the visual quality, and exceed the feature content, of traditional maps.
US Topo maps are superior to traditional maps in some ways. Layers that can be turned on and off allow the inclusion of more data and allow users to customize the map. US Topo maps include a high-resolution aerial photograph, something not possible on traditional maps. They are cast on modern datums and coordinate systems, and include the US National Grid (features that may not be obvious to casual users, but which are important for emergency response and other professional uses). Automated production allows a rapid national refresh cycle (3 years, as opposed to 45 years for the original 7.5-minute map series), which leads to continuous and relatively rapid product improvement.
- Data sources for US Topo maps are documented in a metadata file attached to each map file. See the product users guide for help finding and viewing the metadata file.
- The primary policy document for federal government mapping is Office of Management and Budget (OMB) Circular A-16. One of this circular's objectives is to reduce duplication of effort in federal mapping. Circular A-16 links: