Nt Topo Maps

[Germain Aguilera]

USTopo map production is transitioning away from a static 3-year refresh cycle. Nevertheless, maps will continue to be updated and published annually. Areas experiencing significant change since the last published map will be reproduced. Click here see the most up-to-date US Topo production schedule.

Thank you for your patience as we make this adjustment to better meet the needs of our users. More information will be shared as we finalize our new production cycles. Want the best available National Map data on a custom, on-demand, USGS topographic map? Click here to learn about topoBuilder and OnDemand Topos.

US Topo maps are produced by the National Geospatial Program of the U.S. Geological Survey (USGS). First launched in 2009, US Topos combine the familiar look and feel of legacy paper USGS topographic maps with technological advances of the 21st century.

US Topo map data is derived from the geographic information system (GIS) data of The National Map and is continuously updated via National, state, local, and commercial partnerships. Current and historic USGS topographic maps are available for immediate download from The National Map Downloader. Please note that not all features on historical maps appear on US Topos.

Get your topographic maps here! The latest version of topoView includes both current and historical maps and is full of enhancements based on hundreds of your comments and suggestions. Let us know how we can continue to improve access to the USGS topographic map collection.

This interface was created by the National Geologic Map Database project (NGMDB), in support of the topographic mapping program, managed by the USGS National Geospatial Program (NGP). Geologic and topographic mapping have a long tradition together (see 1888 report). The NGMDB project is proud to assist the NGP in bringing these maps to the Web.

US Topo Series added to topoView

We've added the US Topo series to topoView, giving users access to over 3 million downloadable files from 2009 to the present day. The US Topo series is a latest generation of topographic maps modeled on the USGS historical 7.5-minute series (created from 1947-1992). Like the historical topographic mapping collection, we've added a variety of file formats previously unavailable for the US Topo series, including GeoTIFF and KMZ.

New functionality driven by your feedback

The latest version of topoView is full of enhancements based on hundreds of your comments and suggestions. We've added the ability to preview maps within the interface and give you tools to compare any historical map with maps of the present. Filters and searches work seamlessly with the map records table to get you the info you need with fewer clicks. Accessing the information you need is easier and quicker than ever. As always, your feedback is important to us so don't hesitate to let us know what you'd like to see in future releases!

Calvert County has produced a large scale topographic map series covering the entire county. The maps are in PDF form and have a scale of 1:100. In other words, 1 inch on the map equals 100 feet on the ground. The PDFs are intended to be printed on 24 inches by 36 inches (ARCH D) size paper. Printing on smaller paper will result in the scale no longer being 1:100. This map series is being made available free of charge and each page is available for individual download. Download sizes generally range between 5-7 MB per page. Please read the sidebar included on each map to understand the intended uses and limitations of this map series.

To facilitate finding the proper map sheet, we have provided this interactive map. Simply pan and zoom to your area of interest, then click inside your desired grid square. Select "More info" in the resulting popup will download the map or display it in a new window, depending on your browser settings.

On Garmins site it lists two different Topo map sets you can buy. The 24K and 100K. Maybe this is a really stupid question but what is the difference between the two? Also can you buy the entire US or do you have to purchase each region separately?

The 24k comes in smaller sets because it has much more detail. It has routable streets and trails, but the latter does not do a lot of good because it has far less coverage of trails and fireroads than the standard garmin topo. Its detail has helped me find the right side of ridges in areas where neither maps show trails, but think about what you will be needing and whether it is compatible with your gpsr.

The 1:24,000 are like the 1:24,000 printed USGS topo maps - although I have heard little, if any, of the trail information is in the Garmin product. The 1:100,000 product is more generalized, like the printed 1:100,000 maps and uses metric contour elevations converted to their foot equivalents. The 100K product has been around for a few years, while the 24K started being released this winter and only covers part of the country so far. The prerecorded micro cards allow them to be used in more than one GPSr, but not with MapSource and would require changing cards if the adjacent State is not on the same card. The DVD/CD version may be locked to one GPSr (100K is not locked, posts on 24K say yes and no), can be used in MapSource to select a smaller area of interest and add other mapsets (Garmin, 3rd party, your own). I do not remember about autorouting.

I just purchased the North Central 24K DVD and loaded Montana maps onto my Oregon 300. I was really surprised with the inclusivemess of forest roads (dirt roads). It's a giant leap in road detail even over the custom maps available for free. Garmin seems to have scoured the internet looking for government published off-road and trail data, verified it, and included them in this excellent mapset.

For instance; there is a Helena city trails shapefile available online from the local government website. It is the only place that dataset is available and Garmin included it in the 24K mapset. I'm really amazed.

Earlier topo mapsets from Garmin left alot to be desired. In my opinion they hit a homerun with this new 24K product. Forget the 400T/550T versions of Oregon/Colorado handhelds. Get the units without paying extra for Topo2008 and get this mapset for your area instead. Not only do you get maps that you can peruse on your PC, you'll also get alot more data with much better accuracy.

To simplify - think of a digital photograph. Higher megapixels = more detail. With topos, the opposite applies. Smaller designations = more detail for the topographic map details. 24K is better than 100K as others have said.

In areas of high relief (say rock spires) the 100k contours look sandblasted and some detail that shows on 24k may be totally erased on 100k. Check out Spider Rock in Canyon De Chelly. On most 100k maps it's just a misplaced POI.

If you have a GPS with terrain shading the 100K topos only have an infused 30 meter DEM whereas the 24K series has a 10 meter DEM. The difference in the detail on the terrain shading is very noticeable. Relating to this, the Montana, and I would assume soon to be other models, utilize the Digital Elevation Model (thing used for terrain shading) to calculate some values relating to elevation such as the Vertical Distance to Destination field. In my experience the 10 meter Digital Elevation Model is very accurate (as is the 30 meter but with a bit less detail.)

I would disagree. 24K maps are also more accurate on locations. A 100K paper map is not that detailed and drawn at a 100K scale. So the fact that the locations are not real accurate does not make any difference on a peper map. Unlike a paper map, you can zoom in on a 100K map on your GPS. Thus, on you GPS you can see the inaccuarcies of the 100K map. While on a paper map, the inaccuracies do not make a difference, but they make a difference on the GPS because you are using the map on a scale it was not intended to be used on. 24K maps are created on a different and more accure scale so they are more accurate on locations and when you zoom in, they are 4 times as accurate.

Here is another way to look at it. When you zoom in and out on your GPS, features are drawn at different resolutions and some things only show when you zoom in. Different zoom levels have grids with different spacing. Lets say you have a 10 mile section of a road. At zoom level 10 it would be drawn with 4 points and at zoom level 0 it would be drawn with 16 points. Using a 24K map would be like seeing the road drawn at level 0 with 16 points. Using a 100K map is like using the level 10 map with its 4 points when you zoom in.

Contour interval and the DEM resolution determines how accurate the contour lines are. I beleive the contour lines in Garmin 100K and 24K maps are the same as the USGS Maps. The maps you get from places like gpsfiledepot are normally more accurate than the USGS data. You can download elevation data (DEM) of various quality and resolution from USGS servers. We will normally use higher resolution DEM than the USGS maps so the free maps will generaly be more accurate than the USGS/Garmin maps. But its not that simple. For example, the DEM data I have used to create topo lines has 9 times the resolution of the USGS maps, but if I use the same contour interval, there is not that much difference in where the contour lines are. If I use a contour interval twice that of the USGS maps, it would still not be 9 times as accurate-it would only be about twice as accurate.

3a8082e126