how good is google earth.....

Re: how good is google earth.....

I run the engineering and survey department for my company and I use Google earth all the time and I have found it to be quite accurate for measuring distance. I once used it to measure a site that was around 2,500 ft long and when it was measured out in the field Google earth was only a few feet off.
 
Re: how good is google earth.....

The only thing I have found wrong with google earth measurements is it does not account for changes in elevation. So if you are using it to range things in the mountains it reads only the horozontal distance. So if there is a 1000' elevation difference the LOS will be a little longer than the horozontal that GE reads. But I still use it all the time.
 
Re: how good is google earth.....

If you want to measure the rise/drop of the terrain, just measure from point A to point B, then save it.

Now on the left side you will have a new Line Measurement. Right click on it and "Show elevation profile"
 
Re: how good is google earth.....

IIRC this will give you a terrain elevation profile, but won't give actual LOS range measurement. Either way it has been close enough for my purposes give or take a cosine.
 
Re: how good is google earth.....

True. But when you range something on Google earth and get the range on the computer then you range the same spot with your lrf it will be different due to the cosine difference.
 
Re: how good is google earth.....

If you know the difference in altitudes then take the inverse tangent of altitude difference devided by google earths measured distance will give you LOS, so thats TAN^-1(H/L). If you want to find the actual distance, which the LRF gives you, you take that angle and do (google distance)/cos(LOS).
 
Re: how good is google earth.....

There are free smart phone programs that will give you distance/altitude/angle between two points. For my android they were "Latitude" and "GPS essentials". The gps'd yardages were very accurate with them.
 
Re: how good is google earth.....

in areas of hills and such it's not clear how accurate Google Earth or GPS is... since the 'distance' calculated is by methods not described in their docs. I think it gets pretty close, but to avoid doubt completely a Terrapin LRF is the real deal.