Satellite Photos - Bing vs. Google vs. ?

[Dsanduril]

This season we've started using and come to rely on OvitalMap for our satellite photo caching (tip o' the hat to Feelin' Good for leading us to that). We find it easier than GE2KAP, Google Earth, VentureFarther, etc. (no relationship, just like it). One of the things that has happened is we now find it much easier to use multiple satellite photo sources, so we frequently end up with both Bing and Google photos cached on the iPad. And it seems that in the end, where they have detailed coverage (that's a huge caveat) Bing seems to have more detail than Google. Google's 'selective availability' seems to remove things that are of a lot of interest to us sailors (you know, reefs and such) while Bing seems to leave them in place. Bing also seems to do a bit better with the false color work and that makes it easier to notice offlying reefs and shoals.

An example from North Astrolabe Reef below - there is a rock with a lighthouse and reef in the center of the lagoon, Google has it fuzzed out entirely, Bing shows it quite well (I used the circled coral heads as well as lat/long to make sure the photos are of the same location). Don't know if Google thinks the (inoperative) lighthouse is critical infrastructure that needs to be protected, but for whatever reason the one bit of land in this wide stretch of water is just not shown. Nor is the reef that surrounds it, which is more my concern.

In the end we compare both and use the best for a particular location, but curious about other people's general experience and what other sources people use?

[conachair]

Interesting, thanks.
I've just had a look around on SASplanet, from past passages google wins some but bing or yandex seem better elsewhere. One river in the UK bing would have been better as the images were closer to low water than google, while another shallow spot in Portugal the opposite is true with google closer to low water.
So pays to shop around and check them all before downloading

[Peio]

View of the NGA chart #83572 overlayed upon Google Maps imagery in the GeoGarage platform :



--Peio

[Suijin]

Originally Posted by Dsanduril

An example from North Astrolabe Reef below - there is a rock with a lighthouse and reef in the center of the lagoon, Google has it fuzzed out entirely, Bing shows it quite well (I used the circled coral heads as well as lat/long to make sure the photos are of the same location). Don't know if Google thinks the (inoperative) lighthouse is critical infrastructure that needs to be protected, but for whatever reason the one bit of land in this wide stretch of water is just not shown. Nor is the reef that surrounds it, which is more my concern.

I believe Google uses an algorithm to fill in what it determines is non-essential to save on storage space and speed loading. They have also stated in the past that some of their data providers simply don't have it as it is not of interest to the majority of their customers I doubt that it has anything to do with security (although certainly they do that for some features).

That said, if it's the result of automated filling, the algorithm is going to make mistakes and blot out what to us are important features. It probably decided that the area was open water and so not important.

[Emerald Sea]

We've done-away with GE2KAP over a year ago in favor of Ovitalmap on our iPads (with GPS) and find it more friendly to upload/update GE or Bing images and use while route planning or navigating at the helm. Ovitalmap also allows tracking, pin placement, grid/coordinate placement and other features.

Particularly useful in the many areas where available charts are inaccurate.

[Dsanduril]

I think the big concern for me is missing the 'fuzz'. I know we're not the major use case for Google or Bing, but we do find the pictures invaluable in out of the way corners of the world that will likely never be surveyed again (at least until it can be done fully from space).

There have been several times I've been tempted to buy the actual images from DigitalGlobe - I know of spots where they have half-meter resolution photos that are quite complete but that are low res when viewed in the free versions. You get what you pay for