Map Scale
Whether it’s your backyard or an entire continent, when you create a map you are representing features on the earth. Clearly, in order to represent the features on a map, they must be reduced – or scaled – from their true size to fit on the map.
Map scale is often defined as the ratio of a single unit of distance on the map to the corresponding distance on the ground (for example, one inch on the map may represent one mile on the ground).
With Ortelius it is easy to set the scale of your map.
Three Ways to Scale:
1. Manually set the scale based on widely accepted map or drawing plan scales (used when a specific scale is desired).
2. Calibrate the Ortelius drawing canvas by measuring distances of known objects that are being traced (for example, when tracing an aerial photograph or existing map).
3. Zoom-factor scaling based on imported map data (e.g., Shapefiles) (Ortelius Professional Edition – coming soon).
Manual Scale Setup
To manually set scale, choose File > Drawing Setup from the main menu. From the drop-down list, select the map scale to be applied. Alternatively, set a specific scale by entering the ratio of drawing units to map units and scale will be adjusted accordingly.
Calibrating Scale
When tracing an existing map or aerial photograph, it is often easiest to calibrate the drawing scale based on the image that is being traced.
You will need a known ground-distance from the image in order to calibrate the scale (on a scanned map or photograph, this can be an existing scale bar or a recognizable feature for which you know the length).
Make the Ruler tool sticky and measure the distance between two known points. Initially the ruler shows an arbitrary distance. Next, calibrate the drawing to the proper scale.
Choose File > Scale from the main menu or double-click onto the ruler to open the scale calibration window. Enter the ground distance of the length measured, for example 635 meters, and the scale will be adjusted accordingly. Ruler, scale bar, and drawing are now calibrated to the proper scale.
Printing to Scale
Many of the Ortelius templates are pre-scaled maps and drawing plans using specific, widely accepted drawing scales and various paper sizes. Note that when your printer’s paper size is smaller than your drawing canvas, Ortelius can tile the drawing over multiple printed pages to “print to scale,” or fit to a single page by modifying the File > Print > and check “Fit to Single Page.”
