Random geographic coordinates (on land, avoid ocean)

Question

Any clever ideas on how to generate random coordinates (latitude / longitude) of places on Earth? Latitude / Longitude. Precision to 5 points and avoid bodies of water. <

Answer 1

Supplementary to what bsimic said about digging into GeoNames' Webservices, here is a shortcut:
they have a dedicated WebService for requesting an ocean name.

(I am aware the of OP's constraint to not using public web services due to the amount of requests. Nevertheless I stumbled upon this with the same basic question and consider this helpful.)

Go to http://www.geonames.org/export/web-services.html#astergdem and have a look at "Ocean / reverse geocoding". It is available as XML and JSON. Create a free user account to prevent daily limits on the demo account.

Request example on ocean area (Baltic Sea, JSON-URL):

http://api.geonames.org/oceanJSON?lat=54.049889&lng=10.851388&username=demo

results in

{
  "ocean": {
    "distance": "0",
    "name": "Baltic Sea"
  }
}

while some coordinates on land result in

{
  "status": {
    "message": "we are afraid we could not find an ocean for latitude and longitude :53.0,9.0",
    "value": 15
  }
}