TREWMTE ET AL,
First off, I feel bad getting all of this expert advice for free - my client is paying me my normal hourly analysis rate of $300.00/hour, so if one of you wants to be engaged and paid, please PM me and I will get you contracted.
The attorney I am working for tried working with local LE, but the local LE did not have the skill set or knowledge to go through the process I (we/you) are going through now. I do expect /hope local LE will act if we can identify the real identity of the harasser.
I have the AT&T Subpoena response and list of parties I can forward to someone (once engaged and determined to be free of conflicts).
I was not aware of the concept of grid systems.
From old notes Google Earth uses GPS grid (or 'datum'), which is/was WGS 84 (I have a note that it would be revised in 2012, but I've not had reason to follow it up.)
On a national basis, other grids may be the standard. In the US it is/was something called NAD83. In Europe we have at least two systems, and I know that nationally there are not infrequently at least one other system for each country.
All have latitudes and longitudes, but there are variations a NAD coordinate may not be in exactly the same spot as a WGS coordinate. There are conversion functions, but at the sight of them, my latent math phobia awakens.
Some locations are obtained through equipment that produces NAD or GRS or … what have you. Others are triangulated 'manually'. For equipment important to national infrastructure … such as some AT&T equipment, perhaps … the last choice just might be a possibility, to avoid having to rely on a method that may not be available when it is needed.
And if you buy a dedicated GPS receiver, you quite often find that it can be configured to return coordinates in WGS, NAD or some European system. It's WGS that has been transformed – and in this case, the numerical 'stability' of that transformation become important you don't want a lot of rounding error.
It's rather messy. Forensic geodesy, anyone?
There are conversion functions, but at the sight of them, my latent math phobia awakens.
Well, that is why I provided a pointer to
http//
besides the calculator/converter there are references to most grid reference systems and related resources.
Among them OP might probably make use of this one
http//
to verify the data he has (and that understandably he cannot publicly share)
jaclaz
What do you do for a living?
TREWMTE ET AL,
First off, I feel bad getting all of this expert advice for free - my client is paying me my normal hourly analysis rate of $300.00/hour, so if one of you wants to be engaged and paid, please PM me and I will get you contracted.
The attorney I am working for tried working with local LE, but the local LE did not have the skill set or knowledge to go through the process I (we/you) are going through now. I do expect /hope local LE will act if we can identify the real identity of the harasser.
I have the AT&T Subpoena response and list of parties I can forward to someone (once engaged and determined to be free of conflicts).
I looked at this many years ago (also I had a bit of an interest as Pilot), no notes at hand but ISTR that the basic problem between the different systems is the way that they approximate the shape of the Earth - its not a sphere, it is described as an oblate spheroid. Different mapping systems use subtly different approximations.
The standard is now pretty much accepted as WGS84
I have nothing to hang this on but also seem to remember that the errors when converting between lat and longs in one system to another were different in different parts of the world. But in general the errors were in the order of a maximum few 10's of metres (they would need to align reasonably well or we would never be able to find our way anywhere and would make the whole concept of lat and longs irrelevant).
So if you are trying to establish that the bad guy was in a particular neighbourhood I wouldn't worry. If you need to know that he was on the South East corner of the junction of Oxford Street and Regent Street then it may become relevant.