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Failing to convert XYZ to DMS

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Adi17
(@adi17)
FNG Member

Hi reader,

Could someone please help to just explain how to do the conversion, any link or formula? I am happy to study and do the rest, just need to be pointed in the right direction

The situation is:-

I work in Railway as a track maintainer and have very little knowledge of GPS coordinates and surveying.

I am trying to make a KML file to use in google earth to easily navigate along the track for locating signalling assets.

I have a list of locations(Melbourne, Australia) in a spreadsheet whose coordinates are in geometry(XYZ) format and I am trying to convert it to Lat Lon in DMS so I can make KML file. I checked the majority of converters online available but I am struggling to understand how to do the conversion. By using google map I extracted Lat and Lon in DMS. Can some please help?

For example, in the spreadsheet, I have the following XYZ data:-

X: 16151807.3405 Y: -4566010.7186 Z: NaN

When I track the location on google map I found the value in Lat Lon is

Lat: 37° 54' 17.91383" S
Lon: 145° 5' 38.94994" E

.Thank you 

Adi

 

Quote
Topic starter Posted : October 29, 2021 7:10 pm
JOHN NOLTON
(@john-nolton)
200+ posts Member

Adi   one thing I see right off is you have something wrong with your X coord. Please check you data.

I have one question for you;  for the Z coord. what is   NaN

I am sure that Australia has some transformation software but you can get up on the internet and go to NGS web site and use their software.

JOHN NOLTON

ReplyQuote
Posted : October 29, 2021 8:19 pm
Adi17 liked
Bill93
(@bill93)
5,000+ posts Member

@john-nolton 

NaN is computerese for Not a Number, meaning it has no usable value.

Someone should be along eventually who can tell how to convert what appears to be a projection grid system used there.

Perhaps this will help with an overview

https://parametricmonkey.com/2020/04/08/understanding-australias-coordinate-systems/

ReplyQuote
Posted : October 29, 2021 8:29 pm
Adi17 liked

JOHN NOLTON
(@john-nolton)
200+ posts Member

@bill93   They use Lat, Long and elev. just like we do he in the good old USA; except their Lat. is -(minus) and their Long. is East.

JOHN NOLTON

ReplyQuote
Posted : October 29, 2021 8:33 pm
Bill93
(@bill93)
5,000+ posts Member

@john-nolton 

His X and Y look like their version of USA State Plane systems or UTM. He needs to get from whichever system that is to lat-lon of its datum, and if that isn't close enough then to whatever datum Google uses.

ReplyQuote
Posted : October 29, 2021 8:39 pm
Dave Karoly
(@dave-karoly)
10,000+ posts Member

The lat/long goes to a RR near Melbourne

UTM Zone 55 South

X=332448.39

Y=5803015.65

 

ReplyQuote
Posted : October 29, 2021 8:52 pm

Dave Karoly
(@dave-karoly)
10,000+ posts Member
Posted by: @bill93

@john-nolton 

His X and Y look like their version of USA State Plane systems or UTM. He needs to get from whichever system that is to lat-lon of its datum, and if that isn't close enough then to whatever datum Google uses.

They aren’t UTM. Australia seems to use UTM according to their version of NGS.

ReplyQuote
Posted : October 29, 2021 9:03 pm
JOHN NOLTON
(@john-nolton)
200+ posts Member

@dave-karoly  Don't know what is going on yet with his Coord. He has to come back with more information and then I am sure we can help him. Instead of getting more white hair I will let him tell us what system he is on. The first thing I thought of , in this modern day of GPS was ECEF  XYZ coord. There is plenty of information on whatever system he has. It sounds like he is just getting started and wants to learn more (GOOD FOR HIM).

JOHN NOLTON

ReplyQuote
Posted : October 29, 2021 9:07 pm
Dave Karoly
(@dave-karoly)
10,000+ posts Member

This is from the NGS Lat Long to ECEF converter (XYZ):

=============================================================
           Latitude           Longitude      Ellip_Ht   Ellipsoid
 INPUT =   S375417.91383      E1450538.94994 1.000      GRS80    
 =============================================================


  X (Meters)    Y (Meters)    Z (Meters)    ELLIPSOID
  ------------- ------------- ------------- ---------

  -4132382.7775  2883417.1605 -3897127.8659 GRS80
ReplyQuote
Posted : October 29, 2021 9:17 pm

Dave Karoly
(@dave-karoly)
10,000+ posts Member
Posted by: @john-nolton

@dave-karoly  Don't know what is going on yet with his Coord. He has to come back with more information and then I am sure we can help him. Instead of getting more white hair I will let him tell us what system he is on. The first thing I thought of , in this modern day of GPS was ECEF  XYZ coord. There is plenty of information on whatever system he has. It sounds like he is just getting started and wants to learn more (GOOD FOR HIM).

JOHN NOLTON

It doesn’t look like either UTM or ECEF (which requires a Y).

ReplyQuote
Posted : October 29, 2021 9:20 pm
Bill93
(@bill93)
5,000+ posts Member

The lat-lon at zero ellipsoid height converts to WGS84 or similar systems meters

-4,132,382.130
2,883,416.709
-3,897,127.252
so we can rule out that he has world coordinates with the Z missing.
ReplyQuote
Posted : October 29, 2021 9:22 pm
Dave Karoly
(@dave-karoly)
10,000+ posts Member
Posted by: @bill93

The lat-lon at zero ellipsoid height converts to WGS84 or similar systems meters

-4,132,382.130
2,883,416.709
-3,897,127.252
so we can rule out that he has world coordinates with the Z missing.

TBC has a bunch of choices for Australia.  I tried VICGRID but it doesn't look the same:

 

1 2508280.098 2399567.190 -4.694 RR
ReplyQuote
Posted : October 29, 2021 9:43 pm

Dave Karoly
(@dave-karoly)
10,000+ posts Member

I tried a bunch of different choices for Australia but none of them fit in TBC.  I even tried UTM Zone 54.

Maybe the RR has their own map projection.  The source of the XY data hopefully has information about the source.

ReplyQuote
Posted : October 29, 2021 9:52 pm
JOHN NOLTON
(@john-nolton)
200+ posts Member

@dave-karoly   Dave, give your self a rest. Let Ari give us the details of the projection. Also remember that the UTM south of the equator has a + 10 000 000 meter added to the North Coord.(x (small x, not large X used in ECEF coord.)).

I am sure we will hear back from Adi17

JOHN NOLTON

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Posted : October 29, 2021 10:12 pm
GeeOddMike
(@geeoddmike)
1,000+ posts Member

Once you resolve what Cartesian system your coordinates are in you can use tools at the following site:

https://www.icsm.gov.au/datum/gda-transformation-products-and-tools

In your post you refer to converting XYZ to DMS. You further explain you mean latitude and longitude. You provide an XY coordinate but not a Z. Likewise the geographic coordinate you provide are only latitude and longitude but no (ellipsoid height).

Earth Centered Earth Fixed XYZ coordinates can be readily transformed into Latitude, Longitude and ellipsoid height with a number of web-based tools like this one:

https://geodesy.noaa.gov/TOOLS/XYZ/xyz.shtml

BTW doing the computations by hand yields decimal degrees which are easily converted to degrees, minutes and seconds. 

This leads me (and other posters) to believe your Cartesian coordinates are plane coordinates in some system. What was the source of your coordinates?

 

ReplyQuote
Posted : October 29, 2021 11:44 pm

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