Any GPS *GURUS* here?

[flying dog]

Folks,

 

Situation is this:

 

I have a text file with "squillions" of points which I want to become WAYPOINTS for the GPS.

 

I know how to do that, but there is no DATUM declared in the file.

 

I don't think it is WSG84 - the default for flying.

 

How can I find out/work out what the datum is before importing them to the GPS?

 

 

[Guest basscheffers]

post a few lines from the file for us to look at?

 

 

[CraigRat]

What format is the file (CSV, GPX etc)?

 

Usually it is implied that it's WGS84 unless specified.

 

Can you post the file somewhere or email it to me?

 

 

[flying dog]

Here is a small sample:

 

1746,AARE - 27.3637, 153.25935434.500, 0, 1, 4, 0,AARE

 

2806,AASS - 34.5550, 138.322935434.500, 0, 1, 4, 0,AASS

 

3578,ABAY - 38.4523, 143.40235434.500, 0, 1, 4, 0,ABAY

 

59,ABCH - 33.2853, 151.255235434.500, 0, 1, 4, 0,ABCH

 

1751,ABCK - 27.2047, 152.575635434.500, 0, 1, 4, 0,ABCK

 

23,ABDN - 32.1028, 150.531335434.500, 0, 1, 4, 0,ABDN

 

3569,ABEE - 38.1554, 146.2135434.500, 0, 1, 4, 0,ABEE

 

1744,ABER - 25.80, 151.74535434.500, 0, 1, 4, 0,ABER

 

3570,ABES - 38.2126, 146.62935434.500, 0, 1, 4, 0,ABES

 

24,ABFL - 30.1531, 152.1135434.500, 0, 1, 4, 0,ABFL

 

25,ABMN - 32.4839, 151.255635434.500, 0, 1, 4, 0,ABMN

 

1752,ABON - 27.2536, 153.3335434.500, 0, 1, 4, 0,ABON

 

3591,ABRY - 36.1537, 142.145335434.500, 0, 1, 4, 0,ABRY

 

Ignore the first number. I will change that to X for waypoint.

 

But the other numbers: Well, guess what they are.

 

 

[Guest basscheffers]

What kind of waypoints are these? Obviously not airfields, VFR or IFR ones.

 

Knowing that might give us a clue about what the numbers mean. But on the surface, they look like normal decimal notation coordinates. They just show up in the middle of nowhere.

 

Do you know the WGS84 location of any of these, so we can compare?

 

 

[flying dog]

(Gee you are up early)

 

I don't know where they are as I simply picked the first few of the BIG list.

 

I'd prefere not to say what they are, other than addresses.

 

I can get one or two which I know in WSG84 and post the two for comparison.

 

51,ASHF - 33.5317, 151.73035434.500, 0, 1, 4, 0,ASHF Compared to WSG84 being:

 

S33 53.281 E151 07.482

 

294,BURD - 33.5240, 151.61735434.500, 0, 1, 4, 0,BURD Compared to WSG84 being:

 

S33 52.669 E151 06.259

 

Alas even the WSG ones are APPROXIMATE but close enough.

 

When I load the ones I give, they are "close" but not close enough.

 

 

[flying dog]

Here is a screen grab with the two points.

 

I've taken the liberty of adding a "leading zero" to the number as it doesn't work otherwise.

 

But as you may see, it is a LONG WAY from where it really is.

 

(Oh the grab doesn't show the hand/cursor, so trust me where the red arrow is pointing is where I get the LAT/LONG shown at the bottom of the screen.)

 

 

 

[Guest basscheffers]

Ah, so that's what they are! :)

 

You'd think they might use GDA instead of WGS84, but that would put them off by metres instead of many miles.

 

Maybe a bad conversion from one file format to another? Obviously, decimal -33.53 doesn't become S33 53...

 

I'll keep scratching my head on it.

 

Bas.

 

 

[flying dog]

I tried Aus Geo xx but neither worked.

 

Alas I can't get in touch with whom ever made the list - that would be TOO easy.

 

 

What I also remember when I tried a few waypoints/co-ords, there was no detectable consistancy with them.

 

The one I showed was a few hundred meters WNW. Another one was in a different direction.

 

MAYBE the whole set if numbers are wrong - who knows? Not me.

 

Manually checking them all would take an eternity - as there are probably a few hundred points, and that sort of thing is exactly for what computers are designed. Processing data and doing repetative functions.

 

 

[CraigRat]

You should not be adding a leading 0 to anything as it SHOULD be in decimal Degree format (ddd.dddddd) You need to set your map program up to use it (from that screenshot I can see Mapsource is using ddd mm.mmmm format)

 

Using this I have ASHF out in the Tasman Sea not sure if this is correct as google is returning nothing of substance for 'ASHF'

 

The 5434.500 on the end of the Longitude looks like it's a separate data value and there's a comma missing.

 

Is it possible for you to send me the file so I can have a better look?

 

If you can send it to [email protected] I can pull it apart better and get an understanding of what all thwe data SHOULD be doing and correct any obvious error

 

 

[AlanB]

FlyingDog,

 

I think it's a formatting issue. If you look at the first set of coords from the comparison the lat appears to be deg min sec. ie -33.5317 or -33 deg 53 min 17 sec. This is -33 deg 53.283 min in dd mm.mm This is close to the comparison lat of -33 53.281.

 

The long does appear to have a leading 0 missing. I remember seeing this format when trying to convert some coordinates awhile back using some sharewhere program. It also runs into the next variable without a delineator. The Lon part is 151.730, adding the leading "0" makes it 151.0730 ie 151 deg 07 min 30 sec or 151 07.5 min. This is also close to the comparison lon dd mm.mm of 151 07.482. I agree with CraigRat that the remaining part "35434.500" is another variable, maybe a numeric date format or it may even be two variables without another delineator??

 

There is still 30 ish meteres between the coords and the WGS84 ones you compared them with...is this close enough?

 

Hope this helps.

 

Al

 

 

[CraigRat]

[edit: disregard, just re-read the above and concur]

 

not too sure how the data ended up in the format they have though....quite odd!

 

 

[flying dog]

Alan, Craig,

 

Yeah, most confusing.

 

I'm at work now, so can't do anything.

 

I was thinking of dd.dddd format and didn't try it.

 

But it seems you two beat me to it.

 

I shall try to send you the file soon Craig, it is just I don't know when - probably this evening.

 

 

[Gibbo]

The accuracy I suspect is caused by the resolution of the coordinates.. Four decimal places will only get you to within about 500m. If you have a look at the ERSA points they will always be out by a fraction as they do not provide the accuracy.

 

Some of the IFR GPS plates may be a better soultion if you need some accuracy. Have a look at Melbourne airports coordinates.

 

Gibbo

 

 

[flying dog]

I got lucky and have time to scratch myself.

 

Here is a slightly bigger samle of the data.

 

Oh, why the leading 0 was missing - or is suspected to be missing - is that that data was a concatination of data from excel and so 07 is shown as 7 and so when it is concatinated, you lose the leading 0.

 

Anyway, the full list is probalby 500+ enteries.

 

I don't/can't expect anyone to do it all for me, but here is a somewhat larger sample.

 

Please understand I don't want to divulge too much on what it is, suffice to say the co-oirdinates should be on land, and are "plant" locations.

 

BSMP 148.939 -32.7275

 

ABMN 151.432 -32.8108

 

BLDY 148.499 -32.8664

 

ALBT 147.504 -32.3597

 

APPN 150.789 -34.1928

 

ALPK 150.795 -34.5614

 

ARAL 149.812 -35.6508

 

AUST 150.806 -33.9269

 

ALTN 148.227 -32.8942

 

ATRE 148.393 -31.4908

 

ALDS 149.481 -30.8386

 

AVAL 151.328 -33.6383

 

BANN 149.469 -34.5814

 

BDNE 149.067 -30.9489

 

ABCH 151.434 -33.4728

 

BRGO 150.576 -34.2908

 

ASHF 151.125 -33.8878

 

BRRR 145.287 -31.4019

 

BNTN 151.911 -31.9728

 

ABDN 150.89 -32.1642

 

BALG 151.263 -33.7936

 

BDRN 148.64 -31.8747

 

BRMI 150.468 -32.3875

 

BRTN 149.132 -35.3075

 

ANBO 149.42 -35.765

 

ANNA 152.069 -32.7692

 

BLAK 151.114 -33.9825

 

BLKY 148.973 -34.6739

 

BLAX 150.717 -33.4944

 

BLAY 149.256 -33.5331

 

BICK 148.765 -33.7153

 

BNNA 149.741 -31.6658

 

BOTA 151.202 -33.9461

 

BELT 151.661 -33.0364

 

BHST 148.624 -32.1814

 

BROK 151.106 -32.7492

 

BNYH 152.218 -32.1633

 

BELU 148.553 -33.615

 

BKHM 148.639 -34.8133

 

BLRO 151.623 -32.9547

 

BUDT 148.665 -33.4228

 

BUGL 148.091 -31.9014

 

BWNG 148.818 -34.7667

 

BOWL 150.419 -34.4781

 

BMGA 148.484 -34.8061

 

BECO 151.83 -32.0678

 

BEMA 150.319 -34.4994

 

BRAL 151.959 -32.4728

 

BNRE 148.973 -33.2475

 

BREW 149.761 -33.5081

 

BENI 148.713 -32.2203

 

BWIN 151.596 -32.8356

 

BROO 151.227 -33.5489

 

BUDH 148.212 -32.0564

 

BUPT 151.541 -33.2283

 

BRWD 149.799 -35.4419

 

BMBG 150.441 -33.5364

 

BLVE 151.436 -33.3492

 

BKPK 150.787 -33.6414

 

BAUL 151.001 -33.7694

 

BUEK 149.23 -35.5167

 

BRWG 150.515 -34.5933

 

BRXN 151.351 -32.6586

 

BBOY 150.666 -31.9061

 

BDBE 149.487 -34.7908

 

BRNG 148.801 -31.8131

 

BWLY 150.39 -35.5081

 

BUKN 147.464 -30.8983

 

BOCE 149.723 -32.8336

 

BODA 150.05 -36.0858

 

BNGE 147.804 -33.1064

 

BRUP 147.865 -32.8353

 

BNDH 148.292 -33.9089

 

BULA 152.208 -32.4133

 

BULG 151.018 -32.6522

 

BGRM 148.065 -32.6086

 

BOND 151.273 -33.8883

 

BRBG 148.863 -31.6664

 

BGML 148.293 -33.0236

 

BLCK 152.295 -31.9506

 

BNJK 148.619 -34.9817

 

BURD 151.104 -33.8781

 

BATE 150.185 -35.7144

 

BATH 149.581 -33.4167

 

BALA 149.622 -35.5889

 

BEDG 147.701 -33.3606

 

BERY 150.692 -34.7742

 

BLMR 148.899 -32.195

 

BVDE 149.114 -34.5325

 

BALM 151.178 -33.8567

 

BRWA 149.468 -32.1175

 

BDLA 148.732 -35.395

 

BANR 147.096 -33.2789

 

BDGV 151.716 -32.2978

 

BIAL 149.245 -34.5986

 

BDDN 148.799 -31.5628

 

BANK 151.032 -33.9167

 

BLKH 150.286 -33.6356

 

BLAC 150.908 -33.7706

 

 

[Spriteah]

Plant as in crops? hmmmm.\\\\

 

:big_grin:

 

 

[flying dog]

SSSSSSSSSSSSSSHHHHHHHHHHHHHHHHHHHHHHH!!!!!!!!!!!!!!!!!!!

 

Don't tell anyone!

 

 

[CraigRat]

don't/can't expect anyone to do it all for me, but here is a somewhat larger sample.

I manipulate huge geodata sets all the time with the website I run, I can knock up something and spit it out in whatever format you want (wpt/gpx/kml)... wouldn't take long.

 

 

[CraigRat]

flyingdog, you have a shiny new GPX file in your email with all the points in it!

 

Enjoy!