# Thread: Google maps and its accuracy

1. ## Google maps and its accuracy

Hi all.

Im not sure if you can help understand GPS and mapping system.
I have question on GPS coordinates. Perhaps this is basic question, however I wanted to clarify.

How accurate are google maps? I use a tool to retriever GPS coordinate from the following
Google Maps - Find GPS coordinates, longitude, latitude, altitude

The tools allows me to get a GPS coordinate for any given point. However what im not sure of is how accurate are these coordinate. Do you know how accurate these maps? Or is there a way to findout/calculate etc? If google maps werenâ€™t accurate maps, do you know a map which I can use to get somewhat accurate coordinates?

Thanks

2. You don't need that website to get the lat/lon, you can get that directly from the google maps site. I'm not sure how accurate it is. If you're going off their satellite imagery I wouldn't count on it to be more accurate than 10 ft. You can look into OpenStreetMap , you might be able to get accuracy information from them.

3. It depends on what you mean by "accurate".

In modern usage, when you tell someone (who isn't a professional navigator or cartographer) a latlong position, the implicit assumption is that they're telling you GPS coordinates. From that, you implicitly know where 0"0'N,0"0'E is, and hence every other point can be assigned a unique LL coordinate.

But where 0"0'N,0"0'E is varies depending on your frame of reference. GPS uses WGS84 for example.
World Geodetic System - Wikipedia

If google maps gives you a latlong position, and you tell someone else that position, then they will land up in the same place.

4. Originally Posted by Epy
If you're going off their satellite imagery I wouldn't count on it to be more accurate than 10 ft.
Yeah, when I look for where i'm sitting, it pinpoints the location to like 6 meters away. Still pretty neat, i would say.

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