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Is it possible to determine if a gps point is in water or near(not including elevation) . From what I have seen it doesn't seem possible. I had an idea of somehow getting the gps fence of water bodies and checking if the point lays in the fence. Sounds good but I can't find gps coordinate fences. If any one have any other ideas or a place to get those fences it would be great.

John Bome
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  • If the point is underwater at high tide and above water at low tide, does it count as "in water"? – Pang Jul 20 '16 at 02:54
  • Similarly, if the point is in a river which dried out in winter, does it count as "in water"? Or, if the latitude and longitude indicates that it is in a lake on the map, but the altitude of the point is 2 meters above the water level which is 1.5 meters above sea level, does it count as "in water"? I suggest you to "[edit]" your question and clarify. – Pang Jul 20 '16 at 03:02
  • Sorry, maybe I misunderstood your question. Are you looking for a Google API that checks if a latitude / longitude is defined as water in Google Maps? – Pang Jul 20 '16 at 03:04
  • I am trying to find away if given a gps coordinate is it "in a water body" or the shoreline. Not including elevation . – John Bome Jul 20 '16 at 03:30
  • possible duplicate of [Verify if a point is Land or Water in Google Maps](http://stackoverflow.com/questions/9644452/verify-if-a-point-is-land-or-water-in-google-maps) – geocodezip Jul 20 '16 at 03:53
  • possible duplicate of [I need to know the predefined point is in the sea or on the land](http://stackoverflow.com/questions/3645649/i-need-to-know-the-predefined-point-is-in-the-sea-or-on-the-land) – geocodezip Jul 20 '16 at 04:00

2 Answers2

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You can get the GPS fence for water from OpenStreetMap. Then you do a point in polygon operation, optionally you put all polygons in a spatial search structure, like a quad tree, for a fast polygon search nearby the lat,lon point.

You can start here. and later read more how to identify water in OpenStreetMap

A solution that works on small areas of waters, worldwide, would use much storage space If you concentrate on some countries this should work.

Blu
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AlexWien
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I found that the article is a very interesting approach.

Using google static maps to draw just some pixels around your coordinates, and then check whether its blue or not blue.

You can set a custom unique colour for "water" as a parameter to the google static map, which makes it easy for you to determine if it matches water or not

Blu
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ruedimentaer
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