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Aaron76 Occasional Visitor
Joined: May 24, 2005 Posts: 2
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Posted: Tue May 24, 2005 10:51 am Post subject: How to calculate distance (m) from reference position |
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Hello everyone,
this is my first post on this forum so apologies for being naive or making a fool of myself! My question relates to calculating the difference (in metres) from a reference point.
Essentially I need to ask if I've done this right....
I have a surveyed antenna position, and for a laugh I wanted to see how accurate my GPS receiver actually is. I logged a few hours of data and managed to get it into a *.csv format (so I have time, lat, long and altitude).
I wanted to plot the difference from truth (in metres) from the surveyed point in order to plot a lat/long difference scatter plot. I calculated the difference (in degrees) from the reference point and my logged data for lat/long, I then needed to get this in terms of metres and this is where I'm a bit lost.
From what I've read on the net the following is applicable:
(i) 1 degree Latitude = 111319.5 m
(ii) 1 degree Longitude = R*cos m
where R is 111319.5*COS(Ref latitude)
So, multiplying the latitude difference by (i) gave me the error (distance from truth) in metres, and multiplying the longitude by (ii) gives error in m from ref longitude.
Can anybody confirm that this approach is correct?
I'm keen to hear your opinions.
Best regards
Aaron |
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lbendlin Pocket GPS Staff
Joined: 02/11/2002 22:41:59 Posts: 11878 Location: Massachusetts, USA
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Posted: Tue May 24, 2005 7:25 pm Post subject: |
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Why don't you simply use VisualGPS ? it does all this for you automatically. _________________ Lutz
Report Map Errors here:
TomTom/TeleAtlas NAVTEQ |
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Aaron76 Occasional Visitor
Joined: May 24, 2005 Posts: 2
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Posted: Wed May 25, 2005 8:34 am Post subject: |
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I want to be able to calculate it for myself, as I might be using the data for a report I'm putting together.
If VisualGPS permits data to be loaded in a reference point to be added then it could be useful. I'd still like to know how to calculate the error (m) manually, I'm sad that way!
Thanks for the info - I've never heard of this software. |
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Kepler Occasional Visitor
Joined: May 26, 2005 Posts: 1
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