So, Google just released a static street view api, which is awesome, since showing a streetview of a place will usually jog someones memory much quicker than a top down view.

The only problem with the API (and it may be fixed in a future revision), is that you need to specify the heading that you want the returned image to be facing. This is a problem, since usually you only have the lat long of the place that you are visualizing, and not the bearing from the nearest road that a google streetview car drove along.

However - in my case, I have a complete set of OpenStreetMap data in my places database, so I could:

  • Look for the nearest street
  • Calculate the nearest point on the street
  • Get the azimuth angle between the nearest point and the destination place
  • Convert radians to degrees

And get the correct street view images. See this search for curry on Geonear to see what I mean.

Here’s the code I used (rails code using postgis):

<%= image_tag ".../streetview
  &sensor=false" %>

And in place.rb:

def street_view_heading
  street = nearest_street
  point = Place.find_by_sql(['select st_closestpoint(?, ?) as geometry', street.geometry, self.geometry])
  (Street.find_by_sql(['select st_azimuth(?, ?) as azimuth', point, self.geometry])
    .to_f * 180 / 3.14159).floor

And we’re away. Very nice, thanks Google. :)