Define edges by latitude and longitude

When working with maps for placing data points by latitude and longitude you can work with almost any map image type, e.g., JPG, PNG or SVG.

You will need to set up the map's edges - defined by latitude and longitude - once. The more precise you are with these settings, the more precise positions will you achieve with the later data points.

If you have a map image, and you need to define edges for the first time, I can recommend this approach:

• First, choose projection type - Equirectangular or Mercator. For small area maps (e.g., the size of Denmark) there isn't much difference between the two types. For larger area maps (e.g., all of Europe, South America etc.) it is important to choose the correct type. If you don't know the type, try one or the other. If none of these projections match, the map image may be of s completely different type, but only Equirectangular and Mercator are supported by TARGIT.
• Next, click into the North Latitude field and note where the purple bar is positioned relatively to the map features.
  
• Open Google maps, and click approximately where you think the purple bar is. Google will then tell you the latitude and longitude of that point:
  
• Likewise when you need to find the longitudes:
  
• Type in the Latitudes and Longitudes in their corresponding fields:
  
  Smaller map areas will need more precise values (more decimals).
• Test these settings with some latitude/longitude data:
  
  You may need to adjust the edge values if you find that your data points are slightly out of position.