After downloading a lot of maps from here to review on our site I've come across a lot of differences in the maps. FIRST, I want to be clear, they are all great maps, much better than anything I've seen so far, and I do appreciate Oz, Seldom and maps4gps's time and quality of workmanship. I've been discussing this with maps4gps and he suggested that I bring to your attention also. I made a very temporary page on our site to show the differences which I'll share here.
http://www.in-the-desert.com/temp/garmin.html (http://www.in-the-desert.com/temp/garmin.html) Unfortunately I can't leave this up for too long. I thought maybe you'd like to comment on this. Please in layman's terms, as I'm not a map maker. I do think however that I know what a lot of users would like to see.
Now this is all based on my use on the computer using MapSource 2008 to view them. I will, but have not yet, loaded them into my Garmin E-trex Vista HCx.
Don, what you have to realize is that most of map making on large projects involves combining data from multiple sources. We may manipulate that data a little if it is in a sufficiently standard format so that for instance we can read an attribute that tells us that a road is an Interstate or an unpaved road, but we don't generally survey the roads.
The road data on Desert Southwest and the Topo 2008 in your example were both derived from Census Bureau Tiger files. Those files aren't particularly accurate, but they're free, so they get used a lot. I use OpenStreetMap road data based on the Tiger files. Once I get the data I need to spend a lot more time making it routable, so although the quality of Tiger data has improved since it was incorporated into OSM I'm not going to change my map until OSM updates it's road data, and then it will be a lot of work.
If you want to help make my maps more accurate, learn to use one of OSM's editors to update areas of your particular interest.
This was just for some clarification, as I know nothing about map making. I'm sorry, but helping, the web site keeps me busy, usually 6 days a week. Everything on the site is my doing, so it doesn't leave me with much time, if any. Thanks for the explanation. I'm sure that myself a lot of others don't realize how much work must go into making these maps.
Thanks,
Don....
The green versus tan is just what the BLM/forest service have released saying whether or not the land is theirs. Although there are many different types (BLM, National Forest, Wilderness Area) and they are all coded differently the GPS still just makes them all green.
Thanks Oz for the explanation. You've all been very helpful.
Don...
Sorry but as I said this page was only "temporary" so the link above will no longer work.
Don....