Many people have asked me about accuracy and the Google Earth photos. I tell them it's uneven and to be very careful, don't trust it too far. They often tell me that they are dead on with locations and features visible in google, so I show them this:
Sometimes it takes them a bit, but it usually sinks in;-)
Looks like the old picture of contructing from both ends and meeting at the tie in point.;-)
Yeah, I've noticed a few of them also. But overall it's amazing to me just how good it has gotten lately. Kml a few marks and they are pretty close where they show up on the image (a few feet).
MM-
You've captured the point of reverse one 'manned' railway velocipede !
What keen eyes you have !
Cheers,
TNAI
> Looks like the old picture of contructing from both ends and meeting at the tie in point.;-)
Yea Leonard, and if you look at the wash (don't think it's a road) directly opposite the offset is quite similar. Maybe it's Trimble's fault, since it bears their name...lol
Google is no different than a good GIS. A resource & research tool
Yeah, I've noticed a few of them also. But overall it's amazing to me just how good it has gotten lately. Kml a few marks and they are pretty close where they show up on the image (a few feet).
I USED to think so, but been doing a lot of checks on things like power poles and fence corners lately, and I'm often seeing 8' up to 15', sometimes right on, but more often not on. Could be that the resolution is so much better now and I can zoom in to tight that I'm seeing it better.:-S
I can't blame trimble for this one, lol, just an add on I have. That railroad for a short distance is part of the boundary, sure glad this isn't the area
I have found everything from dead on to several hundred feet off for positions. Nearly everything with a lot of relief ends up distorted. On the flip side it is a way cool tool for the price...
Google Earth, accuracy--Not so hot in this spot
South Tennessee Avenue has been ripped apart and there is double imaging to the right of that and some on the left as well.
Reminds me of my Garmin driving gps. There's a place near my house where every time I drive across the state line it tells me "turn sharply left", even though the road is perfectly straight and always has been.
Google Earth is always right. Maybe an earthquake shifted the tracks 😀
Google Earth uses a spherical Earth; NOT ellipsoidal
Furthermore, the panels are located according to the isocenter so that the further you get to the edge of a photo panel, the greater the divergence of the imagery FROM an orthographic projection.
BUT IT'S FREE.
Google Earth uses a spherical Earth; NOT ellipsoidal
I tell this to my coworkers and clients all the time: google earth is NOT ortho-corrected. If you are surveying in an area with great variations in elevation, the image is not going to line up with your field points.
Another annoyance
I haven't found a place marker in GE that is centered on its coordinates. They use a corner of the symbol so it appears to move as you zoom.
I agree that they are of variable accuracy, and have usually gotten better. I used to see a 75 ft jump between photo panels in one place. Also, it's been a long time and probably fixed now, but I once saw a photo panel in their 3-D view that floated a big rectangle of land a thousand feet above the surrounding terrain.