My phone is able to give me an exact position of my whereabous, using Google Maps I am able to pinpoint my exact location. However, what can the phone telecom company see?
I've read many different forensics cases in my country, and none are able to see the location, only which CellID was used to make the connection. Wouldn't this help in an investigation? Why is the operator collecting this information? Integrity issues? Not needed in order to fulfill their purpose as a vendor?
The phone provider isn't specifically collecting location information, usually. They're collecting usage data about their phone masts, so they can upgrade bandwidth to heavily used ones, plan maintenance out of peak usage hours, and other technical reasons. This includes details about devices which are connecting to a given mast at a given time, since it's useful to determine things like handover.
Google will try to collect more accurate positioning data. They can use GPS to pinpoint phones to within a few metres or so reliably. This can be sent to Google to enable various features like preparing offline maps of commonly visited locations, being able to notify you about travel delays on commonly used routes, and being able to tell you about local services when you search on terms like "restaurant" or "police station". In order to get that data to Google, there needs to be some kind of internet connection active - WiFi or mobile data.
If a criminal is using a phone, and they are sensible, they'll make sure that they've disabled the precise positioning data upload (they can still use Google Maps, if they've got an offline map - that just requires the phone itself to know where it is, and be able to find that on a pre-downloaded map file). That means that the precise positioning data isn't available. However, the cell level data is still around - that doesn't require any data connection, just a standard mobile signal. If the criminal wants to use a mobile during the crime, they can't cover that up. And it doesn't even have to be active use - mobile phones try to connect to nearby masts on a regular basis, so they can receive calls. They'll sometimes try and see if another mast has a better signal, too.
There isn't any particular reason why a phone provider couldn't collect more precise location data - they could pre-load phones they supply with monitoring software, for example. However, it would be a bit of a PR nightmare to deal with. There also isn't any particular reason why criminal investigations can't ask Google for the information, but it tends to be harder to tie a specific device to a location - the data tends to be collected on an account level - and may well involve international requests to get the data, whilst phone provider data will usually be available with a local warrant from a judge in the source country.
To expand on Matthew's answer:
Why is the operator collecting [Cell ID] information?
The cell phone provider needs to know where your phone is so it can route phone calls or internet packets back to your phone. So it must know which cell towers your phone is closest to. But it wouldn't really need to store a history of your cell tower usage to provide service. In some countries, cell phone providers are legally required to record that information, though (for crime fighting reasons)
Aside from this reason, cell tower operators also collect this information because we are living in a time where data is collected whether it seems to be useful or not; since it might turn out to be useful sometime in the future. From a privacy-advocate's view, this is problematic; it allows movement profiles to be created for the whole population. On the other hand, it can also help to find missing persons (people suffering from dementia or children who got lost or ran away from home).
The cell phone operator could in theory pinpoint your location more exactly than just which tower you were close by by using the signal strength of your signal to the two or three closest towers and triangulate your position from that, although this would never be as exact as a gps-determined position.
Wouldn't this help in an investigation?
Sure. But just knowing that a suspect was in the general vicinity of the crime scene, and at what time, is already hugely helpful.
