Google Earth Elevation Datum

I've always understood that GE was WGS84

A Harris, post: 451607, member: 81 wrote: I've always understood that GE was WGS84

Probably using EGM08 geoid model with some type of ITRF coordinates

from GE search
What vertical datum is used in Google Earth

Google Earth implements coordinate system as defined in the OGC KML 2.2 standard.
http://portal.opengeospatial.org/files/?artifact_id=27810

Some additional info can be found here:
https://en.wikipedia.org/wiki/World_Geodetic_System

I have never thought of GE as a reliable elevation source or check. I only use it to get a look at the current and past conditions of a site from plan view and street view. I am curious as to how one might use GE elevation information in surveying. Keep in mind I live in the flat lands.

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global elevation model https://lta.cr.usgs.gov/GTOPO30 , press Get Data in top left menu to get to EarthExplorer.

Yuriy Lutsyshyn, post: 451625, member: 2507 wrote: global elevation model https://lta.cr.usgs.gov/GTOPO30 , press Get Data in top left menu to get to EarthExplorer.

Ahhhh. Global Elevation = GE. Thanks

roger_LS, post: 451603, member: 11550 wrote: Has Google Earth changed their elevation datum? It was always on NAVD88 but when I look today am seeing elevations off some six feet when comparing to a topo I just finished. Then checked in another place and found the same thing. What is going on? I tab back with the historical imagery to 2016 and all is back to NAVD88. Has this happened everywhere? Is this some new datum I don't know about?

Did you do the topo with a fixed 2 meter pole? 6 feet off you could have the rod set at 0 instead of 6.56 feet, or if the range pole was all the way down that is closer to 5 feet. Google Earth is to the nearest foot so a rod height at 0 with either of those rods could be the difference.

I've done some checking between Google and real world elevations. It's my understanding that it is based on a grid at 30m, and I would say that makes sense to what I've seen. Some topos are completely different using Google vs. real world.

Of course, Google would be an awful resource to do any kind of real topo, but as the OP says it can be a sanity check. I don't know if they changed lately, I would say no here cause the few I've checked in flat areas lately check OK for Google (a few feet).

We did run some cross-sections for a flood plain this year. When placed over a Google cross-section Google was in the ball park near the river, but way off near the buildings. That cross-section may have put the house in the flood plain but the real world shows the LAG 7 feet above the BFE, even the bottom of the basement is clear. 🙁

So Google is an iffy resource at best.

Quick check on the newest Google photo at my office base. Control point elevation=3792 Google=3791, this photo is labeled June 2017

maybe a silly question... but how do you even see topo on GE? It never occurred to me to use it for vertical checks.

Andy J, post: 451644, member: 44 wrote: maybe a silly question... but how do you even see topo on GE? It never occurred to me to use it for vertical checks.

The simple way is to hover over the point and the elevation will appear along the strip of info at the bottom of the screen along with the lat and long. You can also do profiles fairly easily, and plot them, maybe you can do more, that's about the extent of my knowledge.

MightyMoe, post: 451645, member: 700 wrote: The simple way is to hover over the point and the elevation will appear along the strip of info at the bottom of the screen along with the lat and long. You can also do profiles fairly easily, and plot them, maybe you can do more, that's about the extent of my knowledge.

That's why I asked...no matter where I move the pointer, it says elev. 0

you must be at sea level;)

Layers / Terrain was unchecked! it goes from 1' to 20' around here depending on the tree coverage. pretty lame.

This is more a question of Google changing their own datum, go back to 2016 and elevations are 6'+- different and wondering if anyone else experienced this. In this area google is usually good within 1' of NAVD88 datum in open areas must be pretty similar to WGS84 in this area. I'm pretty close to the coast so maybe this is why.

I have never found the vertical info in GE to be reliable, but perhaps the fact that I am around 7,000' in elevation has something to do with it. I just checked a point we surveyed earlier this week and find a 15' discrepancy.

We used to bring in google earth surface data and use it for conceptual plans and layouts. It often checked pretty close when we got around to doing the real topo and actual design. (I'm talking within about 1' most of the time - sometimes not)

roger_LS, post: 451666, member: 11550 wrote: This is more a question of Google changing their own datum, go back to 2016 and elevations are 6'+- different and wondering if anyone else experienced this. In this area google is usually good within 1' of NAVD88 datum in open areas must be pretty similar to WGS84 in this area. I'm pretty close to the coast so maybe this is why.

When I scroll backwards in time it always shows the same elevation on my control point. I'm not seeing the 6', but the latest photo I have is june 2017, maybe yours is newer.

@ Andy J

I have have placed the AddOn "Earth Point Topo Map" to GE and when checked it will overlay USGS Topo maps that can be brought in and out of view with a sliding shade bar.
Learned early in my career to scale and put everything on USGS Topo Maps for many reasons.
Use it to get a feel of the property in the estimating and planning stages and to judge difficulty of getting around.
It can be found under View/AddOns..........