dotyb
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Posts posted by dotyb
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Hi all
I'm heading out to Ireland in a week and am looking to track down a decent road map that is downloadable to a Garmin eTrex. I'm also looking for points of interest such as hotels, castles and pubs. (You can see where my priorities are).
Here's what I've found so far:
- The Scottish Mountaineering Club http://www.smc.org.uk/ContourMaps.htm has a great set of contours and peaks.
- http://www.osm4you.com/ has a road map of Ireland that has been exported from Open Street Map data. It's good around Dublin but needs some help in the outer areas.
Does anyone else have other resources for the area that they'd recommend?
Thanks!
-Brian
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I'm the person who generated the California topo map that's been discussed and is hosted here
http://www.vr6.com/gps/map-dl.htm
My map is freely distributed as the 1.03 GB file to be copied onto a 2GB microSD card. I tried to make the download/installation process as simple as possible. Those who do not own Garmin Mapsource or other software can still use it. Those who follow the installation instructions are being successful. The most common glitch seems to be those who don't follow the instructions, and don't put the map file in a folder named Garmin. I also know of one person who had a defective 2 GB microSD card.
Your directions worked fantastically. I was able to transfer the file to my eTrex with absolutely no issues, save the basemap one that I mentioned above. Clear and concise - and convenient too. Thank you for making this available.
For what it's worth, I was able to find the other zip file that you had available on your ftp directory - the one that had the individual .img files of the large CA file. This one actually worked out a little better for me. I was able to download it and import the individual files into Mapsource using cgpsmapper. That way I can load up all or selected portions of California as well as some other areas that I refer to. I was also able to add more detailed roads from Metroguide - on the eTrex, they're overlaid onto the top of your contours. This way, it's the best of both worlds - your fantastic contours and trails and the more recent streets and POIs.
The data I used for roads, trails, powerlines, water features, etc (everything but the contours) was USGS DLG SDTS data files, based on 1:100K USGS topo maps. The only exception is a subset of the San Francisco Bay Area which uses 1:24K USGS DLG SDTS data. I would have preferred to use data derived from 1:24K topo maps for the whole thing but the USGS has provided only small portion of California in 1:24K USGS DLG SDTS data format, and it's an extremely complex patchwork. If there is an alternative complete source for California 1:24K USGS data that I don't have to pay a ton of money to obtain, I'd like to be pointed in that direction.
For what you're using it for, I agree on the tradeoff between current streets and more accurate trails / contours / etc. Most of the information I've found echoes what you've seen in the USGS SDS datasets. I'm not sure what you used for processing the data prior to import, but if you used Global Mapper, you should be able to select the layers you want to keep. That way you could just provide the trails, wells, hydrography, etc and filter out the roads. Let me dig up what I've got in the form of other datasets. I may have come across some other relevant areas for you. BLM boundaries might be handy for you and vegetation sets too.
Names for the roads and water features aren't included in my map because it wasn't apparent to me how to include names and it wasn't important enough for me to try to figure out how to do it.
Tiger data from the US Census bureau might be the way to go for that. Open Street Maps has a large repository of data from Tiger and other sources that's able to be imported. I've only touched on this in the last few weeks though, so I'm new from the GPS aspects. The GIS data I'm a little more familiar with.
You might also be interested in FAA obstruction data (towers, etc), particularly if you're calling in any kind of air support. Airspaces such as Class D, C and B might be handy and frequencies of local CDF or SAR branches might be useful. All that can be georeferenced to the towers or sites.
Contour line on my topo map were derived from USGS DEM data which in turn was mostly derived from USGS 1:24K topo maps (USGS Seamless website, 1/3 arc second dataset). For California, I've seen USGS 1:24K topo maps with contour intervals of 5, 10, 20, 40, and 80 feet, and some have contour intervals in meters. My choice of a 20 foot contour interval for all of California was something of a compromise. It does a better job of resolving terrain features than a 40 foot interval does in those areas where the USGS DEM data came from maps with a 5, 10, or 20 foot contour interval.
I think it was a good compromise and I agree at the utility for 20 ft intervals. I hike and kayak around Sacramento and Nevada County and find having what you describe as being close to ideal.
For SAR, I don't find it to be a significant drawback that my GPS topo map cannot be viewed from Garmin Mapsource. There are better computer-based topo mapping products than the Garmin products. I prefer Maptech Terrain Navigator Pro, which is installed on both my home desktop and the laptop I carry in my SAR vehicle.
See above. Importing it all through cgpsmapper and mapsettoolkit works wonderfully. As far as viewing it from a greater distance, I'd say it's somewhat of a nit. I think it's correctable, but terrain from that distance is hard to distinguish anyway. Is it worth it? Maybe not at this time. It's not quite the product be used for terrain avoidance while flying or driving anyway. Its something that just looks purtier.
It sounds like others who are GIS savvy are developing a California topo map that will include named features, more roads, vegetation type, and perhaps some other data. I'm all for this, please do it. If you develop a better topo map than mine, that would be much appreciated, I'll use your map too. But please consider making a version available with 20 foot contour intervals. If your map is freely distributed, you can use my contour map files in your map if you'd like, perhaps as a separate version. And please please please use dataset(s) that have as much trail, 4WD road, logging road, powerline, etc data as possible.
Again, thanks for making it all available. Though I called it out as a little glitchy on my GPS, I love it and have been marvelling over it since I downloaded it.
-Brian
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First, I have to say that I truly, truly appreciate the work that the community is putting into the generation of these mapsets. It's somewhat of a dream come true. Thank you.
Second, just wanted to add my two cents to the discussion on the VR6 maps of California. In short, the contours are nice, but there are some drawbacks. The data, as mentioned, is a bit old for the roads. Road names are hit and miss depending on the size. The .img is delivered in one gigantic 1.0Gb file, making it a little difficult for the load or processing. The file size also seems to be a little problematic as when I pan around on my Legend Cx, there seems to be some interference with the map and the basemap and the fine data pops in and out as you pan around. Kinda glitchy. I think it pushes the memory limitations of the eTrex. Still, it was better than what I had before.
Finally, I can't donate much to the community in the way of dollars, but I have come across gobs of data for California, Wyoming and other locations. I can provide links if there's something you feel you're missing. I can also provide hosting. My hosting service has a very large pipe for monthly traffic and I'm more than willing to provide a mirror.
Thanks again for all the work.
Free Lake Depth Maps?
in GPS technology and devices
Posted
I'm not sure. Not many states make the bathymetric data for lakes and rivers available for general use, limiting the distribution of the data sets. I've wondered the same thing for kayaking and fishing purposes, myself. Might be time for me to take another pass through state data sets and see if this info is available. If it is, getting it into a Garmin compatible format won't be far behind.
Any state you're looking for in particular?