Thursday, May 8, 2014

Making Charts from Google Earth

We don’t have a chart plotter per se on Momo. Instead, back in 2006 we installed a low-power PC with a decently sized monitor in the nav station space that once housed the electrical panel. Basically, we use a fell-off-the-back-of-a-truck version of MaxSea, which has served us well. Anyway, last year we came across some software that enables you to make charts that are compatible with MaxSea or the open-source navigation software OpenCPN (at this point, we should probably be using OpenCPN, but we suffer from the old-dog-new-tricks syndrome).

Like OpenCPN, the chart-making software is freely available and easy to use – its developer Paul Higgins has indeed provided the cruising community with an invaluable service.

The Googe Earth charts are especially useful in poorly charted reef-riddled areas like Fiji and Indonesia. You can find many Google Earth charts posted on the internet. But since they can be screwed up in a number of different ways, we prefer to make charts of potential anchorages ourselves as we go along.

I don’t really want to discuss at length the virtues and limitations of these charts – they can be made and used in a number of ways and a healthy dose of common sense comes in handy. Instead, I just wanted to post a few images that more or less speak for themselves.

The first set of images features the anchorage at Musket Cove in Fiji. Evidently we came and went, came and went ...

Standard C-Map chart of Musket Cove, Fiji

Google Earth chart of Musket Cove, Fiji

The second set features our anchorage on the island of Rinca in Komodo National Park in Indonesia, where we celebrated Festivus 2013.

Standard C-Map chart of Rinca Island, Indonesia
Googe Earth chart of Rinca Island, Indonesia

And the third image shows our path into an anchorage on the north side of Komodo Island, Indonesia. One of the limitations of the Google Earth charts is that they don’t indicate depths (of course, our “real” charts provide soundings, but in a place like Indonesia you sometimes wonder whether they make it all up). The water here is very deep right up to the shore line. In this case, we were looking for a suitable spot to drop the hook, with me on the bow and Michelle at the wheel. As we slowly inched along, the reef suddenly appeared just a few meters below the surface while Michelle, at the back of the boat, couldn't see the bottom at all. The track on Google Earth chart pinpoints this spot with amazing precision (especially if you zoom in on the chart, which we can't do here).

Standard C-Map chart of anchorage on north side of Komodo Island, Indonesia
Google Earth chart of anchorage on north side of Komodo Island, Indonesia