Just how accurate is Google Earth?

Google Earth (GE) is Awesome. For those that grew up using paper topographic maps and way before GPS and the internet, can really appreciate the efforts put into Google Earth.

Not to mention that the GE Pro version is FREE!!!

The things I could have used GE for 40 years ago.

GE is georeferenced to WGS 84. I am not just sure how GE rectifies its images but it is pretty close to being spot on when cross checking NAD 83 values on known points to the Lat/Long on GE. It is not survey grade level accuracy but it is usable for GIS accuracy.

For example:

Here is a site that four GCPs were established for a mapping site using visible PID markers that can be seen in GE.

The WGS 84 (from GE) vs NAD83 (field survey) residuals are as follows:

Wow that is really close.

Holding point 101 (NAD83) as the common point and transforming the WGS 84 values to this common point the residuals are as follows:

Conclusion

I am blow away at just how accurate GE is once transformed to a known surveyed point.

I really expected the elevation to be off by feet, not by tenths.

The horizontal is spot on. I really was lucky in picking the right point on GE.

I am also calculating everything in grid coordinates to keep each point in the same datum.

I will test other locations to see if the residuals are uniform. My best guess at this point is that each location will vary slightly.

Would I use GE for Lat/Long for GIS mapping, yes I would. It is accurate enough for that type of mapping. You do have to have a good known point to adjust to.

"I fly drones for a living and write DIY surveying math/mapping books for fun!"

Archived Email Posts

If you like the information provided above and would like to see more in future email posts, then consider purchasing some of my books to help support the effort. As all of you know, computer hardware, software and drones costs money. I put 100% of my book sales back into the business to write more books, buy drones to test and so forth.

Thank you all that have supported this effort. It is greatly appreciated.

www.cc4w.net

Unique Surveying Math and Mapping Book Series,

Training and Reference Material Study Guides.

Open Survey Mapping Study Guide here .

Open Surveying Mathematics Study Guide here .

Surveying Mathematics Made Simple Book Series.

One of the biggest hurdles to get through on the FS and PS exams is the surveying mathematics. It takes dedication to study and practice to master the math needed for the exam and throughout your surveying career.

This series of books will provide the necessary tools and step-by-step processes to bring it all together.

Each book in this series will build upon the last one to help you to become a true surveying professional.

Survey Mapping Made Simple Book Series.

Almost anyone can learn to fly a drone. Not everyone can truly master the skills that are required to use a drone for aerial survey mapping and get professional results.

This series of books will provide the necessary tools and step-by-step processes to bring it all together.

Each book in this series will build upon the last one to help you to become a true professional remote pilot.

All books available on Amazon.com

Join Our Mailing List

Surveying Mathematics Made Simple, LLC

Creative Computing 4 Windows

Survey Mapping Made Simple