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barryd Frequent Visitor
Joined: Mar 27, 2004 Posts: 285 Location: Cheshire, England
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Posted: Tue Apr 05, 2005 3:44 pm Post subject: What datum is used for lat/long entry? |
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When using Go to Grid Ref or Add Waypoint in Anquet for PC, one of the input format options is lat/long. Anquet help says "Unlike OS Grid and National Grid, Latitude / Longitude is a global system", from which I assume it means WGS84 lat/long.
However, when I use it the positions look offset from where I'm expecting them to be, which makes me suspect they're OSGB36 datum. Anyone know for sure what it's doing?
[I have emailed Anquet support, but apparently the programmer who wrote it is currently on his/her hols so I may have to wait a couple of weeks to find out!] _________________ Barry Davies
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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 Apr 05, 2005 4:07 pm Post subject: |
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It's WGS84, but you have to be careful about the numeric representation.
Could be DDD.DDDDDD or DDD.MM.MMMM or DDD MM SS etc.
Especially the first two variations get confused very often. the NMEA stream is using variation 2, most programs expect variation 1 _________________ Lutz
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barryd Frequent Visitor
Joined: Mar 27, 2004 Posts: 285 Location: Cheshire, England
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Posted: Tue Apr 05, 2005 4:54 pm Post subject: |
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Hi Lutz,
Thanks for the reply, but my question is about typing in lat/long positions using:
- Map - Go To Grid Reference
- Waypoint - Add Waypoint At
In the Lat/Long tab you can enter degrees, minutes and seconds; or degrees and decimal minutes.
This is where I think it's not using WGS84 datum, which makes it useless for my purposes.
I have asked Anquet again, but just got this response, which makes me feel like a nerd for asking a digital mapping company what datum they use in their own software:
Anquet support wrote: | I'm am informed by a colleague that "we probably use the one GB datum but don't quote me on that"
Its not a question we get asked every day. In fact i believe this is the first time we have been asked this question. I will not be able to get an answer to you for at least three weeks. |
While I've found Anquet friendly and helpful in the past, I'm disappointed by them on this one. _________________ Barry Davies
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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 Apr 05, 2005 5:29 pm Post subject: |
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ok it was just a guess - I have no experience with Anquet 8O _________________ Lutz
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barryd Frequent Visitor
Joined: Mar 27, 2004 Posts: 285 Location: Cheshire, England
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Posted: Thu Apr 07, 2005 8:32 pm Post subject: |
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I get the feeling that I am the only person interested in my thread. Nonetheless, I think it only fair to record that Anquet have now got an answer to me (albeit not the one I wanted). I've suggested they add WGS84 datum as an option to the dialog in the future, as the only time I ever work in lat/long is when using WGS84.
Someone else at Anquet support wrote: | Anquet currently take the input as being on the OSGB36 ellipsoid as you first suggested. There is currently no way to enter WGS84 lat lon into Anquet. |
_________________ Barry Davies
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