title: Simple calculations for working with lat/lon and km distance?
body: <p>Is there a simple calculation I can do which will convert km into a value which I can add to a lat or lon float to calculate a bounding box for searches? It doesn't need to be completely accurate.</p>
  
  <p>For instance: if I were given a lat/lon for London, England (51.5001524, -0.1262362) and I wanted calculate what the lat would be 25km east/west from that point, and what the lon would be 25km north/south of that point, what would I need to do to convert the 25km into a decimal to add to the values above?</p>
  
  <p>I'm looking for a general rule-of-thumb, ie: 1km == +/- 0.XXX</p>
  
  <p><strong>Edit:</strong></p>
  
  <p>My original search for "lat lon" didn't return this result:</p>
  
  <p><a href="https://stackoverflow.com/questions/238260/how-to-calculate-the-bounding-box-for-a-given-lat-lng-location">How to calculate the bounding box for a given lat/lng location?</a></p>
  
  <p>The accepted answer seems adequate for my requirements.</p>