What does "georeferenced" mean?
Georeferencing means that the internal coordinate system of a map or aerial photo image can be related to a ground system of geographic coordinates. The relevant coordinate transforms are typically stored within the image file (GeoPDF and GeoTIFF are examples), though there are many possible mechanisms for implementing georeferencing. The most visible effect of georeferencing is that display software can show ground coordinates (such as latitude/longitude or UTM coordinates) and also measure ground distances and areas. Doing these things with USGS GeoPDF maps requires the free TerraGo toolbar extension to Adobe Reader.
Related Content
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How are different map projections used?
Department of the Interior metadata implementation guide—Framework for developing the metadata component for data resource management
The Department of the Interior (DOI) is a Federal agency with over 90,000 employees across 10 bureaus and 8 agency offices. Its primary mission is to protect and manage the Nation’s natural resources and cultural heritage; provide scientific and other information about those resources; and honor its trust responsibilities or special commitments to...
Obuch, Raymond C.; Carlino, Jennifer; Zhang, Lin; Blythe, Jonathan; Dietrich, Christopher; Hawkinson, Christine
US Topo—Topographic maps for the Nation
Building on the success of 125 years of mapping, the U.S. Geological Survey created US Topo, a georeferenced digital map produced from The National Map data. US Topo maps are designed to be used like the traditional 7.5-minute quadrangle paper topographic maps for which the U.S. Geological Survey is so well known. However, in contrast to paper-...
Fishburn, Kristin A.; Carswell, William J.
Topographic map symbols
Interpreting the colored lines, areas, and other symbols is the first step in using topographic maps. Features are shown as points, lines, or areas, depending on their size and extent. For example, individual houses may be shown as small black squares. For larger buildings, the actual shapes are mapped. In densely built-up areas, most individual...
Georeferenced sea-floor mapping and bottom photography in Long Island Sound
Paskevich, Valerie F.; Poppe, Lawrence J.
USGS Digital Elevation Models (DEM) Switching to New Distribution Format
In support of ongoing efforts to provide efficient, cloud ready, open data formats, the U.S. Geological Survey National Geospatial Program is announcing plans to migrate its 3D Elevation Program (3DEP) Digital Elevation Models (DEM) to a new data delivery format called Cloud Optimized Geotiff (COG) during the first half of fiscal year 2020.
USGS 3DEP Lidar Point Cloud Now Available as Amazon Public Dataset
The USGS 3D Elevation Program (3DEP) is excited to announce the availability of a new way to access and process lidar point cloud data from the 3DEP repository.
Mapping Public Lands in the United States
The Protected Areas Database of the United States (PAD-US) is the official inventory of public parks and other protected areas in all U.S. states and territories.
Using US Topo and Historic Topo Maps on your Mobile Device
Lesson 6a: Using USGS US Topo and Historic Topographic Maps on your Mobile Device - This video demonstrates how to download and use US Topo and Historic Topographic maps on a mobile device.
Elevation
The National Elevation Dataset (NED) is the primary elevation data product produced and distributed by the USGS National 3D Elevation Program (3DEP). The NED provides seamless raster elevation data of the conterminous United States, Alaska, Hawaii, and the island territories. The NED is derived from diverse source data sets that are processed to a specification with a
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PubTalk 11/2004 — From Plane Tables to Pixels
The Revolution in Mapping at the U.S. Geological Survey
by Susan P. Benjamin, Research Geographer
- Mapping the United States in the 19th century was arduous, dangerous work; flash floods, bears, and bandits were just a few hazards
- By the mid-20th century, aerial photography, photogrammetry, and stereophoto pairs, allowed
USGS Topographers at Work
USGS topographers making an electronic distance measurement in a dry lake bed in Saline Valley in Death Valley, California.