Geodetic Coordinates

In all applications I have seen, West has the same effect as minus. Therefore you only use one and pick the one that will be clearer to others you are communicating with.

I believe that the W. designation indicates that it is a negative lon.

:coffee:

Either Or, But Not Both

Lon West or - Lon.

Depends on the convention or program one uses.

But if you see - Lon West, RUN!

Paul in PA

Well, I had an oil company ask me one time, "Kris, our geology department wanted to know if the longitudes were West or East?" (I don't put a minus or West on it due to space on an already packed bunch of well location plats).

I asked if they tried to plot it. He said that had and it didn't come up in the right country if they didn't put West on it. I asked if we were actively drilling in that country. He replied no. I said, well I guess you have your answer then.

Sometimes, people are stupid, and as we all know, you can't fix stupid. However, West indicates "West of Greenwich England" and so does a "-", but I can see some stupid person who remembers a negative times a negative = a positive and plot the damn thing on the other side of the world if you put - and West along with it.

Stick with what you're doing. If it comes up, ask what country it plots in.

West or (-). Either one works for me. It just depends on the programs you are using. Many of the NGS programs specify that you have to enter the - then numbers. No alpha characters.

But in any document I've always used West instead of the (-).

But hey, if some GPS expert wants to try and stake out your coordinates using east instead then I hope he has a full tank of gas. 🙂

A - then a West longitude would be the same as saying an East longitude; kind of like a double negative.

NGS get me a lot...I give a collective DOH! everytime I forget to put a - in front of the long..

I agree with Kris, ask them what country it plots up in!

> Upon looking at some info, I see that maybe there should be a - (minus) sign before the Longitude, Yet I am wondering if the designation of "West" doesn't take care of that and that somehow somone might be confused if the minus sign and West were both there and would think it meant East?????????
>

The designation of West does "take care of that". If the geodetic coords are going to be used in some form of computations are when they are typically shown as being '+' or '-'. I don't think anyone could possibly interpret the erroneous display of a minus sign and 'west' as somehow being a double negative or East longitude. Laypeople would be too stupid to make this jump, and people in the know should know better 😉

I only bring that up because I've, for some reason, done just that in TGO. The program looked at the -W longitude and made it an east longitude. I don't know how many programs convert it that way but Trimble will. Of course using a -E will make it a west longitude. Or -S.....

Just keep in mind that these days, if you have something in the form "XX.xxxxW", a lot of people might assume you have given them "decimal minutes", since that's what a lot of these handheld GPS units use...

The thing about TGO (and Survey Controller for that matter) is that the software will do whatever you tell it to do, even if what you are telling it to do isn't particularly smart.

Don't you just hate that!

From what I've observed, most mistakes, regarding plus (+) and minus (-) as well as North-South and East-West, are made when the sign or label follows instead of leads the number. When people look at 102W, they see 102 and somehow ignore or forget the "W." The situation is similar with coordinates. If it is written or listed as 10328.749S, the number 10328.749 is seen but, the letter "S" is somehow forgotten or ignored. If it is written S10328.749, then the probability that it will be interpreted correctly is greatly increased.

As a note of interest, or dismay as the case may be, there are some NGS programs which require west longitudes to be entered as positive numbers. Talk about confusion and problems when passing data from one program to another!

Do You Mean W075 15 45 Is Confusing ?

Numbers before North Before Latitude and Numbers before West Before Longitude has been a standard for years.

I guess everybody has to do it the only way you know how?

Paul in PA

Since most of us are used to a right-handed coordinate system, East Longitudes are positive (values increase to the right), and West Longitudes are negative (values increase to the left). However, there is no telling what the background is/was of the computer programmer that coded up whatever you happen to be working with at the moment.

Older software coded in FORTRAN required a lot of extra lines of code to accommodate the logic tests for "E" and "W," so much of the programs just expected "+" or "-".

I've seen Geophysical software that expect Longitudes to go 0º to 360º.

In a related vein, Cartographers expect X,Y coordinates, or Easting, Northing.
Surveyors supply Y,X coordinates or Northing, Easting.

then there's X, Y, Z ECEF coordinates.

Which are right-handed orthogonal coordinates with negative signs for the X component West of Greenwich in both Northern and Southern Hemispheres.