The Map | Add | Scale Bar command places a distance scale on your map. The distance scale is relative to the coordinate system used for the map. If the map has a known projection, the scale bar can be set to centimeters, chains, feet, inches, kilometers, links, meters, miles, millimeters, nautical miles, rods, US feet, or yards.
Because of the inherent problems in plotting the globe on a flat surface (see Introduction to Map Projections), scale bars are exact at only one or two latitudes (or Y coordinates) on the map. On large scale maps that cover a relatively small area, such as a single state, the inaccuracies are minor and can be ignored. On small-scale maps, that cover large areas, the inaccuracies become more pronounced but some knowledge of how the scale bars are calculated helps to interpret scale.
On an Unprojected Lat/Long map, the scale bar is designed to match the scaling at the latitudinal center of the map. Scaling is accurate in the north-south dimension over the extent of the map. In the east-west direction, the scale is accurate at the north-south center of the map. Scaling increases towards the poles, and decreases toward the Equator.
On projected maps, check the Show parallel true to scale option to find out where the maps are true to scale. You can also check the projection properties (Coordinate System, click the Change... button) to find out where the map is true to scale.
On maps using Unknown coordinates or projections, the scale bar is based on the scaling at the vertical (Y coordinate) center of the map.
Scale bar properties are located in the Property Manager. The Property Manager contains General and Info pages when the scale bar is selected.
The General page of the Property Manager contains description, cycle spacing, font, and format properties for the scale bar.
Edit scale bar properties in the General page of the Property Manager.
Title text is the text that appears on the scale bar. The default description is based on the measurement option you select. For example, if your page units are in inches, your map is in latitude/longitude, and your scale is in nautical miles, the default text would be, "1 inch on map = # nautical miles" where # is a number. If you want to change the default description, you can enter the desired text into the box. If you do not want a title to appear, delete the text from the Title text box. You can use math text in the Description box for text formatting, or edit description text in the text editor by clicking the button.
The Position option in the Title section places the title text above or below the scale bar. The title bar is always the first line of text when Above is selected. When Below is selected, the Title text is always the last line of text.
Edit the title text Offset by typing a value in page units into the Offset box or clicking the buttons. The offset value determines how far the Title text is drawn from other text or the scale bar, depending on the four Position selections.
Select the units for the scale bar in the Units list. Available units include Centimeters, Chains, Feet, Inches, Kilometers, Links, Meters, Miles, Millimeters, Nautical Miles, Rods, Unit of 1, US Feet, and Yards. If the projection is unknown, Map units are the scale units.
Click the Show units check box in the Description section to indicate the scale units on the scale bar. Select Above or Below in the Position field below Show units to place the units above or below the scale bar.
Click the Show RF scale check box to show the ratio of distance on the map to distance on the Earth's surface. The RF scale has the form of 1 page unit : # scale units. Select Above or Below in the Position field below Show RF scale to place the RF scale above or below the scale bar.
The Parallel true to scale group controls the true latitude text display.
Check the Show parallel true to scale box to display text that indicates the latitude on which the scale bar is based. For any projected map, the scale bar can only be exact for one or two latitudes on the map. This latitude value is indicated by the Parallel true to scale information.
Select Above or Below in the Position field below Show parallels to place the true latitude above or below the scale bar.
Select a scale bar style from the Style list. Available style options include Single bar alternate, Single bar unfilled, Double bar alternate, Double bar unfilled, Comb, Double-sided comb, Rail, and Zigzag.
The scale bar styles include (clockwise from the upper right): Comb,
Double-sided comb, Rail, Zigzag, Double bar unfilled, Double bar
alternate, Single bar unfilled, and Single bar alternate.
Select the number of cycles in the Number of cycles field. Type a number in the Number of cycles box or click the buttons to set the number of cycles.
Set the Cycle spacing by typing a value into the Cycle spacing field. The units for the cycle are selected in the Units list.
Subdivisions can be added to the first cycle by clicking the Show subdivision check box. Select the Number of subdivisions for the first cycle by typing a number in the box or clicking the buttons.
If you have used the selection handles to size the scale bar, click the Default Scale Bar Size button to return the scale bar to its original size.
Edit scale bar line properties in the General section. See the line properties help page for more information on editing scale bar line properties.
Change the display angles of the scale bar labels by typing a value in degrees into the Angle (degrees) field. You can also adjust the label angle by clicking and dragging the bar. Select Above or Below in the Position field in the Labels section to place the labels above or below the scale bar.
See the font properties and label format help pages for more information on editing scale label font and format properties.
Using Map | Scale with Unprojected Latitude/Longitude Maps