USGS 24k Legacy Topo Map
Created By: Boyd
Page Last Updated: January 7th, 2023 7:01am
West: 86.6667° East: 66.8924°
Country: United States
State: Connecticut, Delaware, Indiana, Kentucky, Maine, Maryland, Massachusetts, Michigan, New Hampshire, New Jersey, New York, Ohio, Pennsylvania, Rhode Island, Tennessee, Vermont, Virginia, Washington D.C., West Virginia
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### Map updated on 1/7/23 to add full coverage of Ohio plus expanded coverage of Indiana, Kentucky and Michigan (1764 new quadrangles). ###
The United States Geological Survey began creating 24k topographic maps in the 1940's and completed the series in 1992 with revisions continuing through 2006. Starting in 2009, the USGS began replacing these legacy maps with their new digital "US Topo" series which have less detail. In discontinuing the legacy maps, the USGS explained:
"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."
In spite of their age, many people still consider these to be the "gold standard" of topographic mapping due to their rich detail and a sense of style that is missing from the digital US Topo series.
This map is an all-new curated collection of 7,438 USGS 7.5 Minute quadrangles (about 13 million map tiles) from the USGS Historical Topographic Map Collection and is not available anywhere else. It includes full coverage of Connecticut, Delaware, Maine, Maryland, Massachussets, New Hampshire, New Jersey, New York, Ohio, Pennsylvania, Rhode Island, Vermont, Virginia and West Virginia with partial coverage of Indiana, Kentucky, Tennessee and Michigan. (This is an ongoing project and coverage will continue to expand in the future.)
The newest version of each quad was used unless there were quality issues. About half of the quadrangles are from the period 1950-1969 and another third date from 1980-1999. No legacy maps were available for about 100 quadrangles, so the new digital US Topo maps were used for these.
As you zoom out, the view switches to a mosaic of 275 USGS 100k topo maps and then to a group of 88 USGS 250k maps as you zoom farther. At smaller scales, the USGS National Map Topo Basemap is shown.
Original .tif files were downloaded from the Historical Topographic Map Collection, cropped to remove the collar and re-projected as Web Mercator. These source files were processed at a resolution of 2.4 meters/pixel which preserves the full detail of the original USGS 300 dot-per-inch scans. Do not confuse this map with 24k topos on other sites that are typically based on either the ArcGIS 24k topo or old USGS DRG files.
The ArcGIS topo is actually the old National Geographic "TOPO!" product, with noticeable image compression artifacts and only half the resolution of the boydsmaps legacy topo. Hillshading was also added to these maps by National Geographic, fundamentally changing their appearance.
The other common version of the 24k topo maps is based on USGS DRG (DIgital Raster Graphic) files. These date from the time when online imagery needed to be highly-compressed for storage and delivery. Unfortunately quality suffered as a result, with severe image compression artifacts and too much contrast.
Garmin devices do not offer any serious support for raster imagery, so this map is only available in the free boydsmaps web app. Garmin's "custom maps" raster format only supports a total of 100 tiles at 1024x1024 on most devices, however this map would contain about 800,000 tiles if processed in that format!
The boydsmaps web app is compatible with all devices and operating systems, it's free, there's no advertising and no registration. Use it on your phone like a handheld GPS or on your computer with an interface designed for large screens. It's a website, but can also be installed as an app which offers many advantages, especially on phones. There are over 200 maps, covering the entire world, including the full suite of maps from HERE and Mapbox. Many other features like waypoints, elevation data, weather, radar and more. See the built-in help function for full documentation.
There's nothing to download, just click the link below and start using the map right away!
Note: This map is not hosted by GPSFileDepot