GIS question: In google earth...?

Question

In google earth, turn on the "geograghic features" layer. Compare the arial imagery to the river/waterways vector layer (blue lines). What is the reason for any discrepancy?

Answer 1

Use http://maps.live.com

Answer 2

Sounds like you're answering a homework question.  I just want points, so I'll give you the answer.  When vector features don't line up with aerial imagery, there are a variety of possible reasons:

1.  The aerial image was not registered (positioned) correctly when it was georeferenced.

2.  The vector data was just digitized poorly.

3.  The vector data was digitized at a very small scale, so when you zoom in, you'll see that the person doing the digitizing wasn't right on top of the feature.

4.  The vector data may not be projected correctly, or is using the wrong datum.

Answer 3

layer problem or optical illusion