Almost all historical topographic maps and all US Topo maps produced before June of 2017 were georeferenced using software from the company TerraGo. Those maps are all GeoMark enabled.
GeoMark is TerraGo's geospatial data extension to PDF markup. GeoMark allows notes and geometric objects (lines, polygons, etc.) to be added to a GeoPDF and allows these objects to be exported to GIS files.
Users of the pre-2017 maps can add and export Geomarkup using free Adobe Reader software and the Terrago Toolbar plugin. Exact behavior of the GeoMark tools varies between versions of Adobe Reader and the TerraGo Toolbar. GeoMark functions might not work on USGS topographic maps if you are using older versions of these software tools.
USGS topographic maps (US Topos) created after June 2017 are georeferenced but are NOT GeoMark enabled since we no longer use Terrago software to produce our maps. Some of the capabilities of the Terrago Toolbar are now included in Adobe Reader, and The National Map Viewer (which has seamless contours) has far more capabilities.
Learn more:
- Video Lesson 8a: US Topos Created after June 2017
- US Topo Map Users Guide
- US Topo Map and Historical Topographic Map Users Guide
Related Content
What does "georeferenced" mean?
Georeferencing means that the internal coordinate system of a digital map or aerial photo can be related to a ground system of geographic coordinates. A georeferenced digital map or image has been tied to a known Earth coordinate system, so users can determine where every point on the map or aerial photo is located on the Earth's surface. The relevant coordinate transforms are typically stored...
What is a GeoPDF®?
A GeoPDF is a georeferenced PDF file, meaning that it is a Portable Document Format (PDF) file with added information that relates the image to coordinates on a map. GeoPDF files can be used as plain PDF files but have the added capability of some limited mapping functions (turn any map layers on and off, obtain XY coordinates for a location, measure length, and more).The USGS currently produces...
How do US Topo maps differ from historical USGS topographic maps?
Historically, USGS topographic maps were made using data from primary sources including direct field observations. Those maps were compiled, drawn, and edited by hand. By today's standards, those traditional methods are very expensive and time-consuming, and the USGS no longer has funding to make maps that way. A new USGS topographic map series was launched in 2009 and branded "US Topo." Though...
How accurate are US Topo maps, and why don't they have an accuracy statement?
US Topo maps are as accurate as the data sources used to make them, but because these sources are many and varied, it is not possible to make a single simple statement that the map as a whole meets a particular level of accuracy. US Topo maps, therefore, do not have a traditional accuracy statement in the map collar. Accuracy information for individual data sources is included in the metadata file...
Can I import a US Topo map into my Geographic Information System (GIS)?
Most Geographic Information System (GIS) vendors do not yet provide geospatial PDF import capabilities. US Topo maps are derived from GIS data sets and are formatted as PDF for the benefit of non-specialist users. We consider the product to be primarily an output of—rather than an input to—GIS. However, we recognize the demand for symbolized maps in GIS, and we are working on a companion product...
How current are US Topo maps?
US Topo maps are updated on a three-year production cycle (maps covering one third of the country are updated each year). The US Topo production schedule follows the U.S. Department of Agriculture's National Agricultural Imagery Program (NAIP) collection schedule. This does not include US Topos for Alaska, which are on a different schedule. The linework features shown on the maps are generated...
Related Content
- FAQ
What does "georeferenced" mean?
Georeferencing means that the internal coordinate system of a digital map or aerial photo can be related to a ground system of geographic coordinates. A georeferenced digital map or image has been tied to a known Earth coordinate system, so users can determine where every point on the map or aerial photo is located on the Earth's surface. The relevant coordinate transforms are typically stored...
What is a GeoPDF®?
A GeoPDF is a georeferenced PDF file, meaning that it is a Portable Document Format (PDF) file with added information that relates the image to coordinates on a map. GeoPDF files can be used as plain PDF files but have the added capability of some limited mapping functions (turn any map layers on and off, obtain XY coordinates for a location, measure length, and more).The USGS currently produces...
How do US Topo maps differ from historical USGS topographic maps?
Historically, USGS topographic maps were made using data from primary sources including direct field observations. Those maps were compiled, drawn, and edited by hand. By today's standards, those traditional methods are very expensive and time-consuming, and the USGS no longer has funding to make maps that way. A new USGS topographic map series was launched in 2009 and branded "US Topo." Though...
How accurate are US Topo maps, and why don't they have an accuracy statement?
US Topo maps are as accurate as the data sources used to make them, but because these sources are many and varied, it is not possible to make a single simple statement that the map as a whole meets a particular level of accuracy. US Topo maps, therefore, do not have a traditional accuracy statement in the map collar. Accuracy information for individual data sources is included in the metadata file...
Can I import a US Topo map into my Geographic Information System (GIS)?
Most Geographic Information System (GIS) vendors do not yet provide geospatial PDF import capabilities. US Topo maps are derived from GIS data sets and are formatted as PDF for the benefit of non-specialist users. We consider the product to be primarily an output of—rather than an input to—GIS. However, we recognize the demand for symbolized maps in GIS, and we are working on a companion product...
How current are US Topo maps?
US Topo maps are updated on a three-year production cycle (maps covering one third of the country are updated each year). The US Topo production schedule follows the U.S. Department of Agriculture's National Agricultural Imagery Program (NAIP) collection schedule. This does not include US Topos for Alaska, which are on a different schedule. The linework features shown on the maps are generated...
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