Generate HTML-Map from image

Is there a way of automatically generating a HTML-Map compatible list of coordinates of polygon-like objects (e.g. countries on a map) with very distinctive borders?

Example image:

Final output:

<map id ="ceemap" name="ceemap">
    <area shape="poly" coords="149,303,162,301,162,298,171,293,180,299,169,309,159,306,148,306,149,303" href="austria.html" target ="_blank" alt="Austria" />       
    <!-- ... -->

Any tools/scripts extracting the coordinates of a polygon-like selection would be helpful.


Open the map in Inkscape. If it is a bitmap, use Path -> Trace Bitmap to trace the edges. Clean up the vector data to include only the paths that you want to appear in your imagemap. Save the document, I suggest to a POVRay file. Now you have a list of vertices (and plenty of markup or metadata that you don't care about) in a plain text format. Converting from that to the requisite HTML syntax is still a problem, but not nearly as complex as the first step.

For what it is worth, there is a long standing feature request for Inkscape to include an option to export HTML image maps.

Thanks for your help!

Although Jonathans hint to use the Sobel filter definitely would work, I chose Sparrs approach of first converting the bitmap into a vector image (via Inkscape) and then processing the SVG file. After studying some of the basics of the SVG spec, it was pretty easy to extract the - for HTML image maps needed - X/Y coordinates from all the other junk and generate a suitable code.

Although it’s no rocket science, someone might find this piece of code useful:

// input format: M 166,362.27539 C 163.525,360.86029 161.3875,359.43192 161.25,359.10124 C ...
private static void Svg2map(string svg_input)
	StringBuilder stringToFile = new StringBuilder();

	// get rid of some spaces and characters
	var workingString = svg_input.Replace("z", "").Replace(" M ", "M").Replace(" C ", "C");
	// split into seperate polygons
	var polygons = workingString.Split('M');
	foreach (var polygon in polygons)
		if (!polygon.Equals(String.Empty))
			// each polygon is a clickable area
			stringToFile.Append("<area shape=\"poly\" coords=\"");
			// split into point information
			var positionInformation = polygon.Split('C');
			foreach (var position in positionInformation)
				var noise = position.Trim().Split(' ');
				// only the first x/y-coordinates after C are relevant
				var point = noise[0].Split(',');
				foreach (var value in point)
					var valueParts = value.Split('.');
					// remove part after comma - we don't need this accurancy in HTML
					// comma for seperation - don't worry, we'll clean the last ones within an area out later
			stringToFile.AppendLine("\" href=\"targetpage.html\" alt=\"Description\" />");
	// clean obsolete commas - not pretty nor efficient
	stringToFile = stringToFile.Replace(",\"", "\"");

	var fs = new StreamWriter(new FileStream("output.txt", FileMode.Create));

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