Any data analysts here?

[T.C.]

I am posting this in the hope that there maybe someone here or knows someone who maybe able to assist me.

We are dealing with a serious brain injury case where a cyclist got hit by a passenger coach.

The rider was wearing a personal GPS system at the time and so we have managed to get an overlay of the route the cyclist took.

However, the overlay is very basic, and the QC running the case has asked if I can find someone who can analyse the raw data and produce a more detailed report of that data.

We hold the raw data and so data protection is not an issue, but client confidentiality is.

We have gone back to the head office of the GPS manufacturer who provided the basic overlay in the first place, but they cannot or will not go any further than that on the basis that they are not experts as such and therefore will not be prepared to put their head above the parapit if it went to trial.

Obviously it has to be someone with credibility and expertise in this field and of course it pays a fee.

If you can help, or if you know someone that can help, then perhaps you could advise me and I will be happy to provide more information or follow up and speak to anyone that can.

Thanks in anticipation for any help you can provide.

[Dalemac]

I'm a software engineer - I spend most of my day working with data.

What info do you have and what info are you looking for?

if the GPS data you have is .gpx format it is essentially just an XML file with latitude/longitude co-ordinates and a timestamp. - very plain and basic stuff to analyse.

From those, we can probably calculated average speed between the GPS points.

Like i said, it depends exactly what you want from the data.

Dale

[T.C.]

Hi Dale.

I have no idea what format it is, it is not an area I have any knowledge of, suffice to say that I have actually learnt a lot this morning having found an expert who has given me a brief lesson in how they work.

I did not know that GPS is owned by the US Military and we the public are allowed to use it as a concession, but the public GPS is only accurate to 100 meters +/-

We have managed to plot the route along with speed and elevation, but we needed to get it narrowed down further so that we can plot the left and right hand turns to within a meter, which apparently requires specialist software which in turn will allow us to plot the route onto an ordnance and Survey map.

The overlay onto the Google maps by the GPS company was useful but very basic, but the raw data is being sent to the expert who will be able to advise how much further they can narrow it down.

So I think for the moment, the problem is resolved, but I appreciate your input.

[Dalemac]

Hi Dale.

I have no idea what format it is, it is not an area I have any knowledge of, suffice to say that I have actually learnt a lot this morning having found an expert who has given me a brief lesson in how they work.

I did not know that GPS is owned by the US Military and we the public are allowed to use it as a concession, but the public GPS is only accurate to 100 meters +/-

We have managed to plot the route along with speed and elevation, but we needed to get it narrowed down further so that we can plot the left and right hand turns to within a meter, which apparently requires specialist software which in turn will allow us to plot the route onto an ordnance and Survey map.

The overlay onto the Google maps by the GPS company was useful but very basic, but the raw data is being sent to the expert who will be able to advise how much further they can narrow it down.

So I think for the moment, the problem is resolved, but I appreciate your input.

OK, well you know where to come if you need a second opinion.

The entire system is maintained by the US government, however anyone with a GPS receiver can legally use it.

It's not a question of whether there is extra data available in the file - a LAT/LONG co-ordinate is just that - you cannot go changing it. Your expert will need to determine the accuracy of the GPS receiver and see whether it can even be used.

Anyway, good luck with the case.

[D-Rider]

Hi Dale.

I have no idea what format it is, it is not an area I have any knowledge of, suffice to say that I have actually learnt a lot this morning having found an expert who has given me a brief lesson in how they work.

I did not know that GPS is owned by the US Military and we the public are allowed to use it as a concession, but the public GPS is only accurate to 100 meters +/-

I don't think your "expert" is much of an expert, TC.

It is true that years ago there was a difference in the accuracy of basic GPS for Military and Civilian use (at which time civilian use accuracy of 50m was often quoted). However many years ago, Selective Availability (the method by which non military signals were degraded) was switched off and we now get the same stuff.

The actual positional accuracy you can achieve will depend on a number of things including the number of satellites you happen to be receiving, the relative position of those satellites to you and each other and factors that degrade the signals - such as multi-path reflections whereby signals bounce off of things like buildings and take longer to reach you - hence giving a false impression of the distance to the satellite which messes up the trig calculation a bit.
Accuracy in the z-axis (vertical) is less than the x and y axies (horizontal).

Therefore nobody really wants to commit themselves to an accuracy figure as it depends on so many things - though 5m is probably achievable in most circumstances.

There are techniques by which GPS systems can be enhanced to centimetre accuracy but these are probably not what we are talking about here.

The Americans were the first to put their Navstar satellites up there but theirs is not the only GPS constellation. There is also the Russian GLONAS system and Europe is launching GALILEO (though that's not fully up and running yet).
Certainly there are chipsets which combine GPS and GLONAS for added accuracy (and security in case one or other government decides to stop making theirs available or screws up the accuracy again).

[fatboy]

Your 'expert' sounds a bit lazy. A lot of GPS device retailers now boast an accuracy of metres,depending on location/ conditions/user common sense ratio.
As you are paying for this service, Im sure you can find someone that will make a little more effort than quote somewhat dated figures

[T.C.]

Your 'expert' sounds a bit lazy. A lot of GPS device retailers now boast an accuracy of metres,depending on location/ conditions/user common sense ratio.
As you are paying for this service, Im sure you can find someone that will make a little more effort than quote somewhat dated figures

Sorry, I should have pointed out that what I was told was not by the expert we are looking to instruct, but by someone who provided details of the expert who I have subsequently contacted.

The expert we are speaking to is far more circumspect, and appears to know what he is talking about, but this will be clarified once we receive his CV.

In respect of the chap who gave me the "Lesson" and who provided me with the contact details, then I have to say that I was in no position to question what he was saying because I have absolutely no idea about GPS other than I enter a postcode or an address and it directs me to where I want to go

If the "Expert" we are considering is not up to scratch then we will not instruct him "Simples!"

[fatboy]

Hope you get a result !
Between Dale and D-Rider, I do wonder if the bases are not already covered !

[flatlander]

I know someone who makes tracking devices if not could ask them as they provide stuff to all sorts of weitrd outfits and not just the ones Squid wears!