Results 1 to 6 of 6

Thread: Map Scales ?

  1. #1
    mtbr member
    Reputation: UN-COG-KNEE-TOE's Avatar
    Join Date
    Mar 2008
    Posts
    122

    New question here. Topo Map Scales ?

    MY Older Nat Geo TOPO State series maps have 7.5' detail, at level 5 of 1:15375. I am a map Newbie and am a bit confused, is this more or less resolution than 1:24000 scale of the Newest NG Topo maps, would i want to UPgrade to the Newest ones or do i have higher quality maps in this software?
    IN fact, mine are only 4 years old or so, has Nat Geo changed their map resolutions in these newer State series?
    Last edited by UN-COG-KNEE-TOE; 09-08-2009 at 09:14 AM.

  2. #2
    Rep Power: Infinity
    Reputation: NateHawk's Avatar
    Join Date
    Dec 2003
    Posts
    12,044
    As far as I know, the state series have always been and always will be 1:24k scale. Only difference would be the Back Roads Explorer package which is 1:100k, and Alaska which is so big that 1:24k would require massive amounts of work to create and storage. That one will probably get to 1:24k someday, though. The more populated areas usually get more map detail first (consider aerial photos).

    I like my NG Topo! software, but I find I don't use it terribly often because it doesn't handle "tracks" very well. It can download them, but to put one back into the GPS, it automatically converts to a route. I use it more often to print my own paper maps for hiking, because it prints better than most other software.

  3. #3
    mtbr member
    Reputation: UN-COG-KNEE-TOE's Avatar
    Join Date
    Mar 2008
    Posts
    122
    Quote Originally Posted by NateHawk
    As far as I know, the state series have always been and always will be 1:24k scale. Only difference would be the Back Roads Explorer package which is 1:100k, and Alaska which is so big that 1:24k would require massive amounts of work to create and storage. That one will probably get to 1:24k someday, though. The more populated areas usually get more map detail first (consider aerial photos).

    I like my NG Topo! software, but I find I don't use it terribly often because it doesn't handle "tracks" very well. It can download them, but to put one back into the GPS, it automatically converts to a route. I use it more often to print my own paper maps for hiking, because it prints better than most other software.
    Thanks for the reply, actually - i can upload my Topo Tracks into my Edge 705 or Rino easily, i use GPS Babel and just convert the Topo Files to GPX files and import them to my GPS handhelds - it handles the tracks easily this way and it is only a 1 step process. I am attaching a screen shoot of my Topo Software, showing my available SCALES, am i missing something, mine does NOT appear to be 1:24000, unless it is being somehow converted, i am using a Mac and Topo 4.5 software. So, anyone Know if this Higher Resolution than 1:24000?
    Attached Images Attached Images
    Last edited by UN-COG-KNEE-TOE; 09-04-2009 at 04:03 PM.

  4. #4
    Rep Power: Infinity
    Reputation: NateHawk's Avatar
    Join Date
    Dec 2003
    Posts
    12,044
    Yeah...you've got a higher scale than 1:24k right there. It says you've got down to 1:~15k.

    I'm not into jumping through hoops to get my gps files into the right format. I do enough of that crap in GIS. With hiking and biking, if one program can't do what I ask, then there are plenty of other programs that can.

  5. #5
    mtbr member
    Reputation: fesch's Avatar
    Join Date
    Jul 2009
    Posts
    222
    Quote Originally Posted by UN-COG-KNEE-TOE
    Thanks for the reply, actually - i can upload my Topo Tracks into my Edge 705 or Rino easily, i use GPS Babel and just convert them to GPX files and import them to my GPS handhelds - it handles the tracks easily this way. I am attaching a screen shoot of my Topo Software, showing my available SCALES, am i missing something, mine does NOT appear to be 1:24000, unless it is being somehow converted, i am using a Mac and Topo 4.5 software. So, anyone Know if this Higher Resolution than 1:24000?
    My guess is the original source is a paper USGS 1:24000 topographic map. It looks like someone scanned them in. Even if they rectified them, they could not be more accurate than the original source. In general topo map sources are old - like the 1950's or 60's and in most mountainous areas there is no reason for the USGS to update them. Also the contour lines are generalized so they are understandable rather than exactly accurate, so you may find your GPS can provide more detail than a paper map or scanned paper map on a computer.
    fesch
    Riding in snow is for the desperate.

  6. #6
    Rep Power: Infinity
    Reputation: NateHawk's Avatar
    Join Date
    Dec 2003
    Posts
    12,044
    Yeah, NG Topo! is based on 1:24k maps. To get the tighter scale, all they do is convert everything to vector graphics, which are then infinitely scalable. So yeah, at 1:15k, you are not seeing any more detail than 1:24k; things just look more spaced out due to the tighter zoom level.

    Private companies seem to be more into updating maps than the USGS is at this point. GeoEye AFAIK, produces the most up-to-date sat imagery, upon which maps will get updated. Things like contour lines VERY infrequently ever change, and mostly during major projects like mining, road construction, and sometimes landslides.

    Quote Originally Posted by fesch
    My guess is the original source is a paper USGS 1:24000 topographic map. It looks like someone scanned them in. Even if they rectified them, they could not be more accurate than the original source. In general topo map sources are old - like the 1950's or 60's and in most mountainous areas there is no reason for the USGS to update them. Also the contour lines are generalized so they are understandable rather than exactly accurate, so you may find your GPS can provide more detail than a paper map or scanned paper map on a computer.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •