QGIS only supports displaying the scale in the same units as your map frame. So if the units of your layers are in meters, you can't create a scale bar in feet. Likewise if you are using decimal degrees, you can't create a scale bar to display distance in meters.</p>
<p>
To add a scale bar:
<ol>
<li>Choose the placement from the <label>Placement</label> drop-down list.</li>
<li>Choose the style from the <label>Scale bar style</label> list.</li>
<li>Select the color for the bar <label>Color of bar</label> or use the default black color.</li>
<li>Set the size of the bar and its label <label>Size of bar</label>. </li>
<li>Make sure the <label>Enable scale bar</label> checkbox is checked.</li>
<li>Optionally choose to automatically snap to a round number when the canvas is resized <label>Automatically snap to round number on resize</label>.</li>
