Garmin Topo Maps 24k Vs 100k
Yrko Philogene
We've mapped every hill and valley for your next great adventure. Now with more detail than ever, this product covers the finer points of the outdoors with topographic maps comparable to 1:100,000 scale USGS maps. It also includes terrain contours, topo elevations, summits, parks, coastlines, rivers, lakes and geographical points.
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.
I have a new Garmin 60Cx and would like to load it with maps for hiking. I have looked into the Garmin Topo 100k CD, and frankly I'm underwhelmed with the quality of the maps. After reading about maps, I gather that my options are either Topo or custom maps, but the Garmin Topo seems very overpriced given what you get.
The Garmin 100K topo maps are pretty good overall for hiking, and have lots of useful features and roads. I feel it is worth the price and is a major step above the base mapping that comes factory loaded. In my region I also have the National Parks 24K topo which is great for those areas covered. I think you will benefit from the 100K mapping.
I have been extremely disapointed with the Topo maps... but still use them often. It is better than staring a blank screen when off road! If needed for a small area you could roll your own that are much better but it ain't easy (I'm just starting to attempt it now) I looked at the hi res garmin topo maps but they simply don't cover anything usefull to me.
As for the 100k maps, they don't have enough information to be useful for me. What I did instead was to create a lot of waypoints and tracks on my GPS, and from those I have a very good set of trails and landmarks to navigate from. Many of the topo maps they use are also out-of-date.
I'm in the same boat as the others. I got a Garmin vista cx for Xmas but couldn't use it without the maps. I bought the Garmin Topo and it's not detailed enough. I need 1:24K but it doesn't appear that Garmin offers it.
I find the 100K topos very useful for caching in rough terrain - especially for bushwhacking . I would love to get 24k for the areas I frequently go to but the 100k helped me so far to avoid any major surprises with large backtracking when bushwhacking (e.g. cliffs, major streams, etc.). They don't have much in terms of roads or trails - but who needs roads or trails when carrying a GPS
I have both, in part because I had the 100k first. But I often use the 100k because it has much better trail information. The trails on the 24k are pretty much nonexistent in the areas where I have planned hikes.
Erickson : thanks for the info regarding trail info on the 24k maps. This seems consistent with Garmin's marketing strategy of never having one product that has all the features of its "lesser" products.
The difference between the two is display. The 24K will have TOPO lines every 40 feet in elevation change while the 100K has them every 160 feet. This can lead to you not being able to detect sharp elevation changes as well.
Personally I have two 24K's for the areas I go most of the time and have removed the 100K from my Oregon 400T model. I load the 24K's for where i will be the next month and now with Birdseye I also load that in the High resolution.
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