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  1. #1

    Converting AGD66 TO WGS 84?

    Tried patching around the net,
    Did not find what I was looking for, looked a bit confusing
    Any good links for a conversion

    From what I have gathered,
    it appears to be +8min S and +8min W to change AGD66 to WGS84
    in the southern hemisphere!

    Warning!
    I could have this horribly wrong!
    Did appear somewhat confusing for this old guy

    Any help would be appreciated,
    Regards,
    Gary

  2. #2

    Re: Converting AGD66 TO WGS 84?

    What is the reason for converting them? If it is to get them into your GPS just switch over to the Datum of the marks, input the marks, then switch back to your normal datum. The gps unit will convert them.

  3. #3

    Re: Converting AGD66 TO WGS 84?

    Quote Originally Posted by O-3 View Post
    What is the reason for converting them? If it is to get them into your GPS just switch over to the Datum of the marks, input the marks, then switch back to your normal datum. The gps unit will convert them.
    That is what I have done in the past to convert 66 to 84.

    Reason I needed to was that I have a map program that is in 66, but prefer to run my gps in 84 and back up the marks in 84.

  4. #4

    Re: Converting AGD66 TO WGS 84?

    Quote Originally Posted by O-3 View Post
    What is the reason for converting them? If it is to get them into your GPS just switch over to the Datum of the marks, input the marks, then switch back to your normal datum. The GPS unit will convert them.
    Sounds like a great idea,
    Did think of that but was somewhat apprehensive just in case I messed up the hundreds of others I have in there

    May give it a go though
    Regards,
    Gary

  5. #5

    Re: Converting AGD66 TO WGS 84?

    "it appears to be +8min S and +8min W to change AGD66 to WGS84 in the southern hemisphere!"

    1. Yes you have that wrong and besides Australia has always been in the southern hemisphere anyway, AGD66 is totally an Australian datum only.

    2. Download this file http://www.icsm.gov.au/icsm/gda/gdatm/national66.zip

    3. Download, install this software, use with file in point #2 above http://www.derm.qld.gov.au/property/...s/gday21cd.exe

    4. There is other conversion software available that will use the same data file but we have modified GDAy to specifically handle marine dDD° MM.mmm' formats.

    5. Note that this conversion is to/from AGD66 & GDA94 with GDA94 being approx 1 metre different to WGS84, which is of little consequence with typical recreational type equipment.

    6. You must first ensure the AGD66 coordinates you intend converting are in fact AGD66 otherwise the output will be entirely useless much like the input.

  6. #6

    Re: Converting AGD66 TO WGS 84?

    [QUOTE=SatNav;1294604]"it appears to be +8min S and +8min W to change AGD66 to WGS84 in the southern hemisphere!"

    1. Yes you have that wrong and besides Australia has always been in the southern hemisphere anyway, AGD66 is totally an Australian datum only.QUOTE]

    Hi there,
    Yes, do realize when there is South in the coordinates, must be south of the equator eh! Just poor grammar on my part

    This is where I got the original info from,
    http://www.fishsa.com/gpsartrc.php
    If it is wrong, after finding the correct reference, we should notify about the error for safety reasons,

    Will do some more research and try to get to the bottom of this
    Regards,
    Gary

  7. #7

    Re: Converting AGD66 TO WGS 84?

    This is the info that was supplied,
    I have read it wrong!
    I scribed 8 minutes when it should have been 0.08 minutes as listed,

    Now, from what I understand,
    You would have to add 0.08 minutes to both Lat and long to adjust to WGS84

    WGS 84 satellite navigational systems (GPS) require an adjustment in position of 0.08 minutes SOUTHWARD and 0.08 minutes WESTWARD to agree with the AGD 66 coordinates listed below.
    Regards,
    Gary

  8. #8

    More Info

    Hi Guys,
    I have a suspicion that the correction to adjust ADG66 - WGS 84 depends on what datum point is used,

    for example:
    the corrections I got above, (South Australia)
    WGS 84 satellite navigational systems (GPS) require an adjustment in position of 0.08 minutes SOUTHWARD and 0.08 minutes WESTWARD to agree with the AGD 66 coordinates listed below.

    Are completely different than the corrections sourced from here in Tasmania


    http://www.utas.edu.au/spatial/locations/spadatum.html

    In the lat/long system, toconvert from AGD66 to GDA94 or WGS84, subtract 5.4 seconds fromlatitude and add 4.8 seconds to longitude. Thus 43°22'06"S145°47'11"E (AGD66) becomes 43°22'01"S145°47'16"E (GDA94). To convert from GDA94 or WGS84 to AGD66, add5.4 seconds to latitude and subtract 4.8 seconds from longitude.

    Have just spent an hour with google, I now give up,
    Will take the easy option as suggested and just change the GPS to 66, enter the data, then change back to 84
    Regards,
    Gary

  9. #9

    Re: Converting AGD66 TO WGS 84?

    1. Yes the block correction AGD66 from/to WGS84 does vary across australia and one reason for using the distortion as mentioned above.

    2. The two examples above are similar but there could be confusion in the way written. One is also in minutes and one in seconds. 0.08 minutes southward increases the latitude, 0.08 minutes westward decreases the longitude. add 5.4 seconds (0.09') to the latitude is assuming you ignore (mathematically) that south latitudes are negative, subtract 4.8 seconds (0.08') from longitude is the same as 0.08 minutes westward.

    3. AGD66 and AGD84 should by now be history and those still using or displaying such coordinates need to review their requirements.

  10. #10

    Re: Converting AGD66 TO WGS 84?

    Tks for the reply,
    Unfortunately, I think a lot of ADG66 locations will be left to the end user to do the conversions
    Regards.
    Gary

  11. #11

    Re: Converting AGD66 TO WGS 84?

    Arround brisbnae it works out to be arround 200m in the direction mentioned I believe.

    As for AGD66 being obsolete...um well yeh.... but some of us have some very usefull old maps and other information drawn on old systems, and being able to convert is ver very usefull.

    My big brother has a full set of old maps of the area pre Burdican dam.....if you can lay you hands on old maps prior to you favorite dam.....oh hell they can be handy....but they will be on old systems.

    cheers
    Its the details, those little details, that make the difference.

  12. #12

    Re: Converting AGD66 TO WGS 84?

    Bit of an update,
    Due to the fowl weather we are having ATM, (blowing dogs of chains here and blowing the crabs out of the sand),
    I had time to do a thorough check on all my GPS plots and marks,

    Found a number of errors, mostly due to the fact that I had not checked on what datum was used and when getting plots from friends, found out that some were 84 and some were 66,

    So it turned out to be a large exercise,

    As recommended here, to enter the AGD66 coordinates, I just changed the GPS to 66 then went back to 84 as required,
    As you could imagine, made a few mistakes along the way

    many thanks to all who made contributions to this thread,
    Much appreciated,
    Regards,
    Gary

  13. #13

    Re: Converting AGD66 TO WGS 84?

    1. Yes large number of errors can be associated with confusion of which datum

    "As recommended here, to enter the AGD66 coordinates, I just changed the GPS to 66 then went back to 84 as required"

    2. A better wording so as not to confuse readers would be "As recommended here, to enter the AGD66 coordinates, I just changed the GPS to AGD66 then went back to WGS84 as required" Many confuse the term 84, is it WGS84 or AGD84?

  14. #14

    Re: Converting AGD66 TO WGS 84?

    Sat Navs info site has moved now to this location:-

    https://www.business.qld.gov.au/indu.../surveying/gda
    Cheers

    Trev

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