USGS QUADRANGLES IN GOOGLE EARTH
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USGS QUADRANGLES IN GOOGLE EARTH
By Thomas G. Davis1, PhD, PE, PLS
and Rollins Turner 2, PhD
INTRODUCTION
QUADS (http://www.metzgerwillard.us/quads/) is a web-based service for visualizing
USGS quadrangle boundaries in Google Earth that provides an easy-to-use framework
for retrieving georeferenced PDF (GeoPDF) topo maps. QUADS also includes USGS
overlays for topographic-bathymetric, hydrographic, and shaded relief maps.
QUADS
The principal component of QUADS is a Google Earth network link that plots
approximate USGS quadrangle boundaries (Fig. 1) and provides direct access to
122,353 GeoPDF maps (TerraGo 2014, USGS 2014a), including scans of the last
historical paper map in all available grid sizes. All quadrangle balloons (Fig. 2) contain
name, primary state, nominal grid size, scale, imprint year, and file size information with
a link to the corresponding GeoPDF map. Use the All maps with this name link to search
for older historical maps or newer current maps in the USGS Topographic Map
Collection (USGS 2014e). See USGS (1995) for a discussion of various map series and
USGS (2000) for a list of topographic map symbols.
Quadrangles are categorized by map series (Table 1) and collected in grid-size
subfolders. Coverage includes the conterminous United States, Alaska, Hawaii, Puerto
Rico, the US Virgin Islands, Guam, American Samoa, Micronesia, Palau, the Northern
Mariana Islands, and portions of Canada. The user is prompted to zoom in if there are
more than 1000 quadrangles in view. If there are no quadrangles within the viewer
bounding box, the Search Results network link will contain an empty folder named
OutOfRange.
GeoPDFs were initially produced by the US Army Corps of Engineers Topographic
Engineering Center, currently known as the US Army Geospatial Center, using existing
digital raster graphics (DRGs). Traditional topographic GeoPDFs produced by the
USGS are created from high-resolution scans of paper maps and compose the Historical
Topographic Map Collection (HTMC) (USGS 2013b). The USGS is engaged in an
ongoing effort to scan all existing paper maps.
The current electronic map series, US Topo (USGS 2014f), is created by the USGS
National Geospatial Technical Operations Center from The National Map (TNM) data
including color orthoimagery. The QUADS database and this document will be updated
periodically to reflect changes in the USGS map offering.
1
Metzger + Willard, Inc., 8600 Hidden River Parkway, Suite 550, Tampa, FL 33637.
E-mail: tdavis@metzgerwillard.com
2
Computer Science and Engineering, University of South Florida, Tampa, FL, retired.
E-mail: rollins@tampabay.rr.com
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Table 1. Topographic Map Series
Series Source Count
US Topo The National Map 55,178
HTMC Historical Topographic Maps 67,175
QUADS is similar in function to the Map Locator (USGS 2012), a Google Maps
application that runs in the user's web browser. The Locator is an outstanding browser
application but lacks the robust user interface and flexibility of Google Earth.
Figure 1. USGS Quadrangles
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Refresh Mode
The Refresh Mode network links provide a uniform mechanism to control the Search
Results and Layers network links. When Refresh Mode is Manual, the contents of the
network links are effectively frozen, allowing the user to pan and zoom without prompting
a network link refresh. This is particularly useful for inspecting overlays or gaining an
overview of network link contents. To initiate a network link:
1. Position the area of interest (AOI) in the viewer.
2. Check the Search Results network link (Fig. 1) to display quadrangle placemarks
and boundaries, or check one of the Layers network links (Fig. 3) to display
USGS ground overlays.
3. On subsequent uses, reposition the AOI and ensure that the network link is
checked and selected. When Refresh Mode is Automatic, search results are
refreshed two seconds after camera movement stops. When Refresh Mode is
Manual, choose Refresh from the Edit menu, or right-click and select Refresh in
the context menu.
The Manual and Automatic network links may be used to stop and start refreshes for the
Search Results and Layers network links. The default refresh mode is Automatic. To
stop refreshes, check Manual; to restart refreshes, check Automatic. Canceling an edit
of network link properties will disable mode selection for that particular network link.
Figure 2. Quadrangle Balloon
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Overlays
Overlay layers (Table 2) are implemented as network links that retrieve multiresolution
images from an OpenGIS-conformant Web Map Service (WMS) (OGC 2006) or via a
Representational State Transfer (REST) export. All requests are directed first to the
QUADS server where bounding box coordinates are conformed to service requirements
before being passed to the service provider.
Table 2. Overlay Layers
Layer1 Resolution2 Service3 Extent4
TOPO! 5 2 REST6 USGS TNM7
TNM DRG 8 2 WMS9 USGS TNM10
Hydrography11
Figure 3. National Geographic TOPO!
Figure 4. USGS Digital Raster Graphic
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Figure 5. National Hydrography Dataset
Figure 6. National Elevation Dataset Grayscale Relief
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Figure 7. National Atlas Color Relief
CONCLUSION
QUADS provides user-friendly, graphically oriented access to a wealth of publicly
available geospatial information maintained by the USGS. Metzger + Willard, Inc. is
pleased to make QUADS freely available to anyone having Google Earth installed on a
computer with an Internet connection.
ACKNOWLEDGMENTS
The authors wish to thank the following individuals for their help in implementing or
testing QUADS: Jeff Wendel and Andy Orona, USGS; Scott Brown, PLS, George F.
Young, Inc.; and Kemp Morris, PSM, Morris Surveying, Inc.
Special thanks are extended to Steve Skelton, USGS.
REFERENCES
EPA (2014). "Mapping Services."
(http://water.epa.gov/scitech/datait/tools/waters/services/mapping_services.cfm)
Esri (2014a). "USA Topo Maps." (http://goto.arcgisonline.com/maps/USA_Topo_Maps)
Esri (2014b). "USA Topo Maps (MapServer)."
(http://server.arcgisonline.com/ArcGIS/rest/services/USA_Topo_Maps/MapServer)
National Atlas of the United States (2013a). "Color Shaded Relief of the United States."
(http://nationalatlas.gov/mld/csr100i.html)
January 2015 7 of 8National Atlas of the United States (2013b). "National Atlas Web Map Services
Introduction." (http://www.nationalatlas.gov/infodocs/wms_intro.html)
Open Geospatial Consortium (2006). "OpenGIS Web Map Server Implementation
Specification." (http://portal.opengeospatial.org/files/?artifact_id=14416)
TerraGo Technologies (2014). "TerraGo Toolbar."
(http://www.terragotech.com/products/terrago-toolbar)
United States Geological Survey (2014a). "About GeoPDF Maps."
(http://store.usgs.gov/locator/about_digital_maps.html)
United States Geological Survey (2014b). "Digital Raster Graphics (ImageServer)."
(http://raster.nationalmap.gov/arcgis/rest/services/Scanned_Maps/USGS_EROS_D
RG_SCALE/ImageServer/)
United States Geological Survey (2014c). "National Hydrography Dataset."
(http://nhd.usgs.gov/)
United States Geological Survey (2014d). "The National Map - Service Endpoints."
(http://viewer.nationalmap.gov/example/services/serviceList.html)
United States Geological Survey (2014e). "US Topo and Historical Topographic Map
Collection." (http://geonames.usgs.gov/pls/topomaps/)
United States Geological Survey (2014f). "US Topo Quadrangles."
(http://nationalmap.gov/ustopo/)
United States Geological Survey (2013a). "Earth Resources Observation and Science."
(http://eros.usgs.gov/)
United States Geological Survey (2013b). "Historical Topographic Maps."
(http://nationalmap.gov/historical/)
United States Geological Survey (2012). "Map Locator."
(http://store.usgs.gov/b2c_usgs/usgs/maplocator/%28uiarea=2%29/.do)
United States Geological Survey (2006). "National Elevation Dataset."
(http://ned.usgs.gov/)
United States Geological Survey (2000). "Topographic Map Symbols."
(http://pubs.usgs.gov/gip/TopographicMapSymbols/topomapsymbols.pdf)
United States Geological Survey (1995). "USGS Maps Booklet."
(http://pubs.usgs.gov/gip/usgsmaps/usgsmaps.html)
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