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Groups > comp.mobile.android > #36070

Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer?

From Reinhard Zwirner <reinhard.zwirner@t-online.de>
Newsgroups comp.mobile.android, alt.windows7.general, alt.satellite.gps
Subject Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer?
Date 2016-11-20 02:26 +0100
Message-ID <e9ccecFrotpU1@mid.individual.net> (permalink)
References (4 earlier) <o0lik3$vs1$1@news.mixmin.net> <V6qdnTIB2fyLs7LFnZ2dnUU78enNnZ2d@brightview.co.uk> <o0o5uj$tb8$1@news.mixmin.net> <e9bt0kFoa9eU1@mid.individual.net> <o0qigk$jhm$1@news.mixmin.net>

Cross-posted to 3 groups.

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Raymond Spruance III schrieb:
> On Sat, 19 Nov 2016 22:03:30 +0100, Reinhard Zwirner wrote:
> 
>> I hope your GPS device is able to handle the map datum: otherwise
>> you'll wonder why the place where you are doesn't correspond to where
>> you should be according to the map.
>>
>> AFAIK default datum with Garmin devices is WGS84.

> Why does the word "datum" matter for this context?
> 
> I don't understand your comment, because I have never had any problem
> whatsoever with USGS maps working on my Android mobile phone, without even
> knowing what a "datum" is.

To give a pair of coordinates to find a certain point on the earth's
surface is useless without knowing the geodetic/map datum:

<https://en.wikipedia.org/wiki/Geodetic_datum>

<quote>

Horizontal datum

The horizontal datum is the model used to measure positions on the
Earth. A specific point on the Earth can have substantially different
coordinates, depending on the datum used to make the measurement.
There are hundreds of local horizontal datums around the world,
usually referenced to some convenient local reference point.
Contemporary datums, based on increasingly accurate measurements of
the shape of the Earth, are intended to cover larger areas. The WGS
84 datum, which is almost identical to the NAD83 datum used in North
America and the ETRS89 datum used in Europe, is a common standard
datum.[citation needed]

For example, in Sydney there is a 200 metres (700 feet) difference
between GPS coordinates configured in GDA (based on global standard
WGS 84) and AGD (used for most local maps), which is an unacceptably
large error for some applications, such as surveying or site location
for scuba diving.[1]

</quote>

See also #4 in the map information on page 1:

<http://education.usgs.gov/lessons/map_margins_2p.pdf>

Hence: if you use different maps _together_ with a GPS device you
must always ensure for correct navigation that the geodetic datum of
the map is the same as the datum which the GPS device uses to compute
your position.

But if you use maps just as a stand-alone navigation tool for, say,
hiking then map datum IMHO can be neglected.

HTH

Reinhard

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Thread

Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? Raymond Spruance III <spruancerayIII@example.com> - 2016-11-16 20:39 +0000
  Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? The Real Bev <bashley101@gmail.com> - 2016-11-16 13:55 -0800
    Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? Raymond Spruance III <spruancerayIII@example.com> - 2016-11-17 05:52 +0000
      Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? "Stephen H. Fischer" <a_nani_mouse@mindspring.com> - 2016-11-16 22:16 -0800
        Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? The Real Bev <bashley101@gmail.com> - 2016-11-16 23:20 -0800
          Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? Raymond Spruance III <spruancerayIII@example.com> - 2016-11-23 03:49 +0000
    Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? Raymond Spruance III <spruancerayIII@example.com> - 2016-11-18 01:05 +0000
  Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? "Bill Bradshaw" <bradshaw@gci.net> - 2016-11-17 09:45 -0900
    Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? Raymond Spruance III <spruancerayIII@example.com> - 2016-11-17 20:26 +0000
      Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? tlvp <mPiOsUcB.EtLlLvEp@att.net> - 2016-11-17 21:18 -0500
        Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? Raymond Spruance III <spruancerayIII@example.com> - 2016-11-19 02:26 +0000
      Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? "Bill Bradshaw" <bradshaw@gci.net> - 2016-11-19 09:30 -0900
        Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? Raymond Spruance III <spruancerayIII@example.com> - 2016-11-19 20:28 +0000
          Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? Raymond Spruance III <spruancerayIII@example.com> - 2016-11-19 20:37 +0000
            Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? "Bill Bradshaw" <bradshaw@gci.net> - 2016-11-20 09:24 -0900
              Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? Raymond Spruance III <spruancerayIII@example.com> - 2016-11-22 01:46 +0000
                Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? "Bill Bradshaw" <bradshaw@gci.net> - 2016-11-22 08:26 -0900
                Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? Raymond Spruance III <spruancerayIII@example.com> - 2016-11-22 20:29 +0000
                Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? "Bill Bradshaw" <bradshaw@gci.net> - 2016-11-23 09:00 -0900
                Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? Raymond Spruance III <spruancerayIII@example.com> - 2016-11-24 02:48 +0000
                Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? Raymond Spruance III <spruancerayIII@example.com> - 2016-12-01 23:44 +0000
                Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? "J. P. Gilliver (John)" <G6JPG@soft255.demon.co.uk> - 2016-12-02 10:26 +0000
                Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? dg1261 <dgREMOVE-THIS1261@cs.com> - 2016-12-03 02:05 +0000
                Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? Java Jive <java@evij.com.invalid> - 2016-12-03 09:20 +0000
                Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? FromTheRafters <erratic@nomail.afraid.org> - 2016-12-03 08:26 -0500
              Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? Raymond Spruance III <spruancerayIII@example.com> - 2016-11-22 04:46 +0000
  Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? Raymond Spruance III <spruancerayIII@example.com> - 2016-11-17 21:01 +0000
    Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? "NY" <me@privacy.net> - 2016-11-17 22:12 +0000
      Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? Raymond Spruance III <spruancerayIII@example.com> - 2016-11-18 00:39 +0000
        Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? "NY" <me@privacy.net> - 2016-11-18 16:36 +0000
          Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? Raymond Spruance III <spruancerayIII@example.com> - 2016-11-19 00:21 +0000
            Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? Reinhard Zwirner <reinhard.zwirner@t-online.de> - 2016-11-19 22:03 +0100
              Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? Raymond Spruance III <spruancerayIII@example.com> - 2016-11-19 22:08 +0000
                Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? Raymond Spruance III <spruancerayIII@example.com> - 2016-11-19 22:54 +0000
                Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? Raymond Spruance III <spruancerayIII@example.com> - 2016-11-20 02:31 +0000
                Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? Reinhard Zwirner <reinhard.zwirner@t-online.de> - 2016-11-20 02:26 +0100
                Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? Raymond Spruance III <spruancerayIII@example.com> - 2016-11-20 02:34 +0000
                Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? tlvp <mPiOsUcB.EtLlLvEp@att.net> - 2016-11-20 03:15 -0500
                Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? nospam <nospam@nospam.invalid> - 2016-11-20 08:24 -0500
                Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? tlvp <mPiOsUcB.EtLlLvEp@att.net> - 2016-11-21 01:40 -0500
                Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? nospam <nospam@nospam.invalid> - 2016-11-21 10:23 -0500
                Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? FromTheRafters <erratic@nomail.afraid.org> - 2016-11-21 16:44 -0500
                Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? Raymond Spruance III <spruancerayIII@example.com> - 2016-11-20 16:54 +0000
                Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? tlvp <mPiOsUcB.EtLlLvEp@att.net> - 2016-11-21 01:51 -0500
                Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? Raymond Spruance III <spruancerayIII@example.com> - 2016-11-22 00:21 +0000
                Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? Raymond Spruance III <spruancerayIII@example.com> - 2016-11-22 04:46 +0000
  Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? "MJP" <KKK@KKK.NET> - 2016-11-18 21:19 +0000
    Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? Raymond Spruance III <spruancerayIII@example.com> - 2016-11-19 02:26 +0000
      Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? Raymond Spruance III <spruancerayIII@example.com> - 2016-11-19 02:38 +0000
      Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? "Stephen H. Fischer" <a_nani_mouse@mindspring.com> - 2016-11-18 19:14 -0800
        Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? Raymond Spruance III <spruancerayIII@example.com> - 2016-11-22 06:15 +0000
          Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? "Stephen H. Fischer" <a_nani_mouse@mindspring.com> - 2016-11-22 00:19 -0800
            Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? Raymond Spruance III <spruancerayIII@example.com> - 2016-11-22 15:15 +0000
              Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? "Stephen H. Fischer" <a_nani_mouse@mindspring.com> - 2016-11-22 10:40 -0800
                Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? The Real Bev <bashley101@gmail.com> - 2016-11-22 11:26 -0800
                Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? nospam <nospam@nospam.invalid> - 2016-11-22 14:34 -0500
                Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? "Stephen H. Fischer" <a_nani_mouse@mindspring.com> - 2016-11-22 13:03 -0800
                Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? Raymond Spruance III <spruancerayIII@example.com> - 2016-11-22 20:29 +0000
  Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? Raymond Spruance III <spruancerayIII@example.com> - 2016-11-19 00:08 +0000
  Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? Raymond Spruance III <spruancerayIII@example.com> - 2016-11-19 20:46 +0000
  Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? Raymond Spruance III <spruancerayIII@example.com> - 2016-11-22 06:15 +0000
    Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? Raymond Spruance III <spruancerayIII@example.com> - 2016-11-23 04:25 +0000
      Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? Raymond Spruance III <spruancerayIII@example.com> - 2016-11-23 17:18 +0000
        Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? nospam <nospam@nospam.invalid> - 2016-11-23 13:00 -0500
          Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? tlvp <mPiOsUcB.EtLlLvEp@att.net> - 2016-11-23 15:13 -0500
            Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? nospam <nospam@nospam.invalid> - 2016-11-23 16:17 -0500
  Re: Best way to view Android GPX track offline on a Windows USGS topo map & elevation chart GPS viewer? Raymond Spruance III <spruancerayIII@example.com> - 2016-12-01 23:44 +0000

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