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Cheers - Bryan
Point Molate Pier
- Thread starter fauxboat
- Start date
Great question, and posting here means at least some other people who could have the same question can see the answer.
Let me confirm: is this the "black box" you are referring to, in the document titled 2022-03-16 18:00: Round the Rocks Sailing Instructions Revision 2 is Posted ?
If so, that's probably a tile from a different pass.
Google maps satellite view works by buying imagery from companies like Maxar, and then breaking the images at each zoom level into little tiles that are easily loaded from the web. That way when you scroll the map sideways they just have to load enough tiles to fill the side of the screen and it appears smooth to you, and as you zoom in they load the tiles for the next zoom level so detail keeps increasing.
But they don't buy new images all the time --- images are expensive --- and so they prioritize getting new land images and leave seas, lakes and bays alone. I don't know why it happened here, but I believe you're looking at a cloudy-day tile getting shown next to sunny-day tiles.
Usually it shows up in the middle of a bay or lake, like this:
Here's the area by the Dumbarton bridge:
If you look you can see different tide cycles, and the shadows on the electrical towers in the top center do not (seem to) match the shadow on the pivoted section of the railroad bridge, which are giveaways that this is a composite image from two or more satellite passes.
Google maps is a fascinating, free service.
Richard, 2023 SSS Race Co-Chair
Let me confirm: is this the "black box" you are referring to, in the document titled 2022-03-16 18:00: Round the Rocks Sailing Instructions Revision 2 is Posted ?
If so, that's probably a tile from a different pass.
Google maps satellite view works by buying imagery from companies like Maxar, and then breaking the images at each zoom level into little tiles that are easily loaded from the web. That way when you scroll the map sideways they just have to load enough tiles to fill the side of the screen and it appears smooth to you, and as you zoom in they load the tiles for the next zoom level so detail keeps increasing.
But they don't buy new images all the time --- images are expensive --- and so they prioritize getting new land images and leave seas, lakes and bays alone. I don't know why it happened here, but I believe you're looking at a cloudy-day tile getting shown next to sunny-day tiles.
Usually it shows up in the middle of a bay or lake, like this:
Here's the area by the Dumbarton bridge:
If you look you can see different tide cycles, and the shadows on the electrical towers in the top center do not (seem to) match the shadow on the pivoted section of the railroad bridge, which are giveaways that this is a composite image from two or more satellite passes.
Google maps is a fascinating, free service.
Richard, 2023 SSS Race Co-Chair