Seeing imperfect orthorectifcation in Google Earth imagery

Yesterday we talked about orthorectification and how it is imperfect, especially when using an inaccurate terrain model. We thought we would have a look at the effect using historical imagery. We used … [Read more...]

Google Earth measurement and image alignment

As we saw last week Google Earth's measuring tools are actually quite accurate when measuring distances based on latitude and longitude, and can even take altitude into account. However, many people … [Read more...]

How Google Earth measures distances

In yesterday's post we mentioned that Google Earth's measurements did not match ours, which used the Haversine formula. So we decided to investigate a bit more. The Haversine formula assumes the … [Read more...]

Numbering the points on a Path or Polygon with KML

We have recently been spending some time improving our JavaScript for combining polygons. In order to debug it, we found it useful to number the points for display in Google Earth. We thought that … [Read more...]

Measuring in Google Earth Pro

Last month Google removed the US$399 a year price tag from Google Earth Pro and released it for free. There is no longer any need to sign up for a licence key, simply login with your email address and … [Read more...]

Measuring distances with the Google Earth Ruler

The "ruler" tool in Google Earth has always been useful, and it has seen a number of improvements over the years. To get started with it, simply go to [Tools] --> [Ruler] in Google Earth and it'll … [Read more...]

Measuring distances with the Google Earth Ruler

The "ruler" tool in Google Earth has always been useful, and it has seen a number of improvements over the years. To get started with it, simply go to [Tools] --> [Ruler] in Google Earth and it'll … [Read more...]