GPS Co-ordinates

[Rodney M]

I appreciate the GPS co-ordinates given on the CycleLab site for the start of the races - but it is interesting to see the errors. It's usually easy enough to sort it out - but the chances are good that sooner or later one is going to end up in the mielie lands in the Free State:

 

 

Druiwefees: GPS Co-Ordinates: S24 42 41.9 E28 24 00,6 E should be S24 42 41.9 E28 24 00.6

 

Fast One: GPS Co-Ordinates: S 26° 36’ 954”; E 28° 03’ 200” should be S 26° 36.954'; E 28° 03.200'

 

Berge en Dale Classic: GPS Co-Ordinates: S26° 3’919” E27° 49.661” should be S26° 3.919' E27° 49.661'

 

[dirtrider]

it is not a proven science !!! Depending on your maps , GPS you may land up anywhere !!

[kosmonooit]

Here's another option than relying on random information: load Google Earth and zoom into the spot, pick up the co-ords from there. Cant be easier. Oh wait, that requires some spatial navigation skill, so that might be beyond the now generations skill set .

Edited December 19, 2010 by kosmonooit

[scotty]

Coordinates are supplied by race orgs, either they are supplying it incorrect or Cyclelab are posting it incorrect.

[dirtrider]

I got over 400 hundered of my sites on mapsource with co-ods . Tom-Tom people gets lost

[Guest Big H]

I looked at the co-ordinates..... it seems to be only the commas and points that differ...... cannot understand your gripe???????

[Rodney M]

I looked at the co-ordinates..... it seems to be only the commas and points that differ...... cannot understand your gripe???????

 

No - it not just the commas and points, it is also the degrees (') and seconds (")and .......

 

As I said in my post - easy enough to work out - but don't try cut-and-paste.

[Tankman]

there are different formats for using co-ordinates, check your gps settings and make sure you are using the same format on your device than the co-ordinates you are given

[Guest Big H]

there are different formats for using co-ordinates, check your gps settings and make sure you are using the same format on your device than the co-ordinates you are given

 

As Tankman says hours:minutes:seconds and hours:decimals

[Guest Big H]

If you have a HP calculator it is easy to converts or go here....

 

http://www.fcc.gov/mb/audio/bickel/DDDMMSS-decimal.html

[jmaccelari]

it is not a proven science !!! Depending on your maps , GPS you may land up anywhere !!

Geez - I hope it is. If it isn't we're likely to have the Yanks dropping their smartbombs on us...

 

The biggest problem is the reference spheroid used. This is typically WGS84, but if a different spheriod is used there can be a difference of a few metres. Not much of a problem for your average race start, but a major problem if you're dropping a ton of munitions.

 

The reference spheroid is a general, static model so it will have deviations from the local datum and will not take into account dynamic effects such as gravity waves.

 

The issue picked up here is not the GPS model, but the confusion of decimals and minutes (. versus ').

 

It's an easy mistake for someone who doesn't understand what they are typing in to make.

[Tankman]

There are three basic forms of a coordinate.

 

1. Coordinate containing degrees (integer), minutes (integer), and seconds (integer, or real number) (DMS).
2. Coordinate containing degrees (integer) and minutes (real number) (MinDec).
3. Coordinate containing only degrees (real number) (DegDec).

All forms of coordinates are capable of representing the same amount of data and the same precision. Depending on which type of coordinate you are provided with, and which type you would like to work with, you may have to do some conversion.

 

See the different formats below for the same location (37º 49' 10" north and 122º 29' 2")