This topic provides illustrations showing how point labels can be placed relative to their defining point locations. For line label positioning see the discussion under the Position tab in the Style: Labels topic.
Offsets apply to labels based on points, not to areas based on areas or lines.
Manifold allows placement of labels to positions that are offset from the point location which defines the label. For example, when labels for city names are included in a map that also shows the city points we would like the labels to be offset slightly from whatever symbols indicate the city locations.
In the illustration at left, above, the labels have not been offset. In the illustration at right, they have been offset by the default angle and offset distance.
To offset labels, in the Symbol tab of the Label Style dialog, we check the Move box and then specify the Angle and offset distance desired. In the illustration we have set the background color for the preview pane to dark gray.
There are four ways of specifying offset distance:
5 means a distance of five points.
5pt means a distance of five points.
10% means ten percent of the size parameter applied to the label, so that a label with a size of 36 points would be offset 3.6 points and a label with a size of 72 points would be offset 7.2 points.
5@ is a relative value meaning 5 points more than the size parameter, with -5@ meaning 5 points less than the size parameter. A label with a size of 36 points given an offset of -5@ would be shifted by 31 points in the direction of the Angle. Negative offsets resulting in values less than zero mean zero offset.
Some users prefer to use the % specification since that automatically scales the offset to the size of the labels: Change the label size and the offset changes proportionately.
We can enter whatever numeric value we want for the Angle, but Manifold will round the resulting angle to place the label at one of eight angle positions. For example, if we enter an Angle value between 22 and 67 the resulting label placement will be the same as if we entered 45 as the Angle.
To keep life simple and to avoid confusing anybody who has to work with our projects months or years after we have created them, most Manifold users will use rounded values only, as shown in the illustrations below.
Manifold also allows using the negative number equivalents, to make it easier to remember where we want to put a label: It's easy to remember 45 degrees as the upper right position, and for most people easier to remember -45 instead of 315 as the upper left position.
We can illustrate how labels are placed based on the Angle specified using the diagram below.
The illustration shows a label using a box. The Move box has not yet been checked in the Symbol tab, so the label appears in the same location as the point which defines the label. The illustration shows the point which defines the label as a green dot.
If we check the Move box and then use an Angle of 270 the illustration shows how the label will appear to the left of the green dot. Entering any Angle between 247 and 292 would have the same effect, since all values in that range will be rounded to 270. If we prefer, we could use an Angle of -90 if we find that easier to remember than 270.
Entering an Angle of 315 will position the label above and to the left of the defining point location. Any Angle value between 292 and 337 will get rounded to 315 and have the same effect. If we prefer, we could enter -45 if we find that easier to remember than 315.
An Angle value of 0 positions the label directly above the defining point location. This is the "due North" position.
An Angle value of 45 positions the label above and to the right of the defining point location.
An Angle value of 90 positions the label directly to the right of the defining point location, the "due East" position.
An Angle value of 135 positions the label below and to the right of the defining point location. 135 is the default Angle. Using 135 as an Angle produces a good, legible, offset effect in most maps.
An Angle value of 180 positions the label directly below the defining point location. This is the "due South" position.
An Angle value of 225 positions the label below and to the left of the defining point location. If we like, we can use -135, which is easy to remember since 135 is the default Angle and is already entered into the Angle box when we first check the Move box.
We can apply the above settings in our example map of cities in France to see how various Angles work in real life. In this example map, the Cities Labels layer contains layers that use the Name field of points in the Cities layer to provide the name of the city.
If we do not check the Move box, no offset is applied. Labels appear at the same location as their defining points.
We can check the Move box and choose an Angle of 0 and an offset distance of 10 points.
That positions the labels directly above the defining point location.
Changing the Angle to 180...
... positions the labels directly below the defining point location, in the "due South" position.
Choosing an Angle of 270 (or the equivalent -90) positions the labels to the left of the points.
Choosing an Angle of 90 positions the labels to the right of the points.
Using an Angle of 45 positions the labels above and to the right of the points; however, using an offset of 10 points positions the labels too far away from the points.
To illustrate an Angle of 135 we will use a smaller offset of only 3 points.
An Angle of 135 is the default, positioning the labels below and to the right of their defining point locations. Using an offset of 3 points, also the default, keeps the labels closer to the points.
Choosing an Angle of 225 (or the equivalent -135) positions the labels below and to the left of the points.
To show placement above and to the left we will enter -45 for the Angle and we will increase the offset slightly to 5 points.
Using -45 for the Angle is equivalent to using 315. It places labels above and to the left of the points.
Rounding - Angles of 360 or greater are flattened to 0. Future builds may provide a more quantized way of choosing Angle values, instead of allowing values like 31 or 37 simply forcing all values between 15 and 45 to 30, for example.
Just one number to remember: 135 - It's easy to remember what numbers to use for Angle to place label text. The key is using negative numbers for hard-to-remember locations. Everybody can remember placing a label at 45 degrees to put it at the top right, and it is just as easy to remember -45 degrees to put the label in the top left. Likewise, it is easy to remember 0 for above the point and 180 for below the point and 90 degrees to the right of the point. If remembering 270 for due West, that is, to the left of the point is not easy, then use -90.
That leaves just one number, 135, to remember, for the lower right position. That one is easy to remember because it is the default, already loaded into the dialog for when we check the box to offset a label. For lower left, use -135.
Choosing 135 as the Angle with 3 points as the offset is using default settings:
Many maps will have good legibility and a pleasant appearance when using default settings:
Style: Thematic Formatting
Style: Bitmap Symbols
Style: Label Icon Placement
Example: Change Point Style - Using new Style pane controls to change point style, either very rapidly one property at a time, or using the total Style button to compose a new style with changes to several properties at once.
Example: Style Pane Quickstart - A tutorial introduction to using the Style pane to apply color, symbology, size and rotation to areas, lines and points in drawings.
Example: Format a Drawing using the Style Pane - In this example we provide a first, step by step look at how to format areas in a drawing using the Style pane. We can specify the same formatting for all areas or use a field to automatically set formatting, a process usually known as thematic formatting.
Example: Format the Size of City Points by Population - A common GIS task is to format the size of points in a drawing based on some value. For example, the size of points that represent cities might be formatted based on the value of the city's population, with cities that have larger populations being marked by larger point icons. This is an example of thematic formatting and is easy to do using the Style pane.