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copied!<p>Well, one obvious problem is that you're parsing the string for every city for every pixel.</p> <p>I would <em>strongly</em> suggest that the first thing you do is convert your <code>placeDataList</code> into a more sensible format - a <code>List<City></code> where each city has properties of <code>Latitude</code>, <code>Longitude</code> and <code>Population</code>.</p> <p>I wouldn't be surprised to find that the vast bulk of your time is being spent performing parsing. There are some other calculations you're repeating over and over, such as <code>(24.443136 / size_h)</code> but I doubt those are as significant.</p> <p>If you can work out some very crude measure for which areas will be covered for a particular city, you could avoid calculating the <em>exact</em> distance each time. For example, you could work out the minimum and maximum values for latitude and longitude which <em>might</em> be within 150 miles, and do a very quick test for each city before doing any more complicated maths.</p> <p>Some stylistic issues:</p> <ul> <li>Use a foreach loop where you can</li> <li>Follow .NET naming conventions, e.g. <code>GetPixelColor</code> instead of <code>getPixelColor</code></li> <li>Think about your names - the parameters for <code>getPixelColor</code> aren't really a width and height, are they? They're a <em>position</em> (e.g. x and y)</li> <li><p>I would generally encourage you to use braces for <em>every</em> loop and <em>every</em> <code>if</code> block. Not everyone goes along with that, but I find this sort of construct to be error-prone and hard to read:</p> <pre><code>for (int i = 0; i < pixel_h; i++) for (int j = 0; j < pixel_w; j++) { pixelColor = getPixelColor(i, j); bmp.SetPixel(j, i, pixelColor); } </code></pre></li> </ul>

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