Lines¶

Code¶

1 * {
2   stroke: black;
3   stroke-width: 3px;
4 }

Details¶

The only rule asks for a black stroke (this attribute is mandatory to get strokes to actually show up), 3 pixels wide.

Code¶

1 * {
2   stroke: #333333, #6699FF;
3   stroke-width: 5px, 3px;
4   stroke-linecap: round;
5   z-index: 0, 1;
6 }

Details¶

Lines in CSS have no notion of a “fill”, only “stroke”. Thus, unlike points or polygons, it is not possible to style the “edge” of the line geometry. It is, however, possible to achieve this effect by drawing each line twice: once with a certain width and again with a slightly smaller width. This gives the illusion of fill and stroke by obscuring the larger lines everywhere except along the edges of the smaller lines.

The style uses the “multi-valued properties” CSS support by specifying two strokes and two stroke-widths. This causes each feature to be painted twice, first with a dark gray (#333333) line 5 pixels wide, and then a thinner blue (#6699FF) line 3 pixels wide.

Since every line is drawn twice, the order of the rendering is very important. Without the z-index indication, each feature would first draw the gray stroke and then the blue one, and then the rendering engine would move to the next feature, and so on. This would result in ugly overlaps when lines do cross. By using the z-index property (Line 3) instead, all gray lines will be painted first, and then all blue lines will painted on top, thus making sure the blue lines visually connect.

The “stroke-linecap” property is the only one having a single value, this is because the value is the same for both the gray and blue line.

The result is a 3 pixel blue line with a 1 pixel gray border, since the 5 pixel gray line will display 1 pixel on each side of the 3 pixel blue line.

Code¶

1 * {
2   stroke: blue;
3   stroke-width: 3px;
4   stroke-dasharray: 5 2;
5 }

Details¶

In this example the we create a blue line, 3 pixels wide, and specify a dash array with value “5 2”, which creates a repeating pattern of 5 pixels of drawn line, followed by 2 pixels of omitted line.

Code¶

1 * {
2   stroke: #333333, symbol("shape://vertline");
3   stroke-width: 3px;
4   :nth-stroke(2) {
5     size: 12;
6     stroke: #333333;
7     stroke-width: 1px;
8   }
9 }

Details¶

In this example a multi-valued stroke is used: the fist value makes the renderer paint a dark gray line (3 pixels wide, according to the “stroke-width” attribute), whilst the second value makes the line be painted by repeating the “shape://vertline” symbol over and over, creating the hatching effect.

In order to specify how the symbol itself should be painted, the “:nth-stroke(2)” pseudo-selector is used at Line 4 to specify the options for the repeated symbol: in particular with are instructing the renderer to create a 12px wide symbol, with a dark gray stroke 1 pixel wide.

Code¶

 1 * {
 2   stroke: symbol(circle);
 3   stroke-dasharray: 4 6;
 4   :stroke {
 5     size: 4;
 6     fill: #666666;
 7     stroke: #333333;
 8     stroke-width: 1px;
 9   }
10 }

Details¶

This example, like others before, uses symbol(circle) to place a graphic symbol along a line.

The symbol details are specified in the nested rule at Line 4 using the “:stroke” pseudo-selector, creating a gray fill circle, 4 pixels wide, with a dark gray outline.

The spacing between symbols is controlled with the stroke-dasharray at line 3, which specifies 4 pixels of pen-down (just enough to draw the circle) and 6 pixels of pen-up, to provide the spacing.

Code¶

 1 * {
 2   stroke: blue, symbol(circle);
 3   stroke-width: 1px;
 4   stroke-dasharray: 10 10, 5 15;
 5   stroke-dashoffset: 0, 7.5;
 6   :nth-stroke(2) {
 7     stroke: #000033;
 8     stroke-width: 1px;
 9     size: 5px;
10   }
11 }

Details¶

The circle portrayal details are specified using the pseudo selector “nth-stroke(2)” at line 6, asking for circles that are 5 pixels wide, not filled, and with a dark blue outline.

Code¶

1 * {
2   stroke: red;
3   label: [name];
4   font-fill: black;
5 }

Details¶

This example paints lines with a red stroke, and then adds horizontal black labels at the center of the line, using the “name” attribute to fill the label.

Code¶

1 * {
2   stroke: red;
3   label: [name];
4   label-offset: 7px;
5   font-fill: black;
6 }

Details¶

This example is line by line identical to the previous one, but it add a new attribute “label-offset”, which in the case of lines, when having a single value, is interpreted as a perpendicular offset from the line. The label is painted along a straight line, parallel to the line orientation in the center point of the label.

Code¶

1 * {
2   stroke: red;
3   label: [name];
4   font-fill: black;
5   label-follow-line: true;
6 }

Details¶

As the Line with default label example showed, the default label behavior isn’t optimal.

This example is similar to the Line with default label example with the exception of line 5 where the “label-follow-line” option is specified, which forces the labels to strickly follow the line.

Not all labels are visible partly because of conflict resolution, and partly because the renderer cannot find a line segment long and “straight” enough to paint the label (labels are not painted over sharp turns by default).

Code¶

1 * {
2   stroke: red;
3   label: [name];
4   font-fill: black;
5   label-follow-line: true;
6   label-max-angle-delta: 90;
7   label-max-displacement: 400;
8   label-repeat: 150;
9 }

Details¶

This example is similar to the previous example, Label following line. The only differences are contained in lines 6-8. Line 6 sets the maximum angle that the label will follow. This sets the label to never bend more than 90 degrees to prevent the label from becoming illegible due to a pronounced curve or angle. Line 7 sets the maximum displacement of the label to be 400 pixels. In order to resolve conflicts with overlapping labels, GeoServer will attempt to move the labels such that they are no longer overlapping. This value sets how far the label can be moved relative to its original placement. Finally, line 8 sets the labels to be repeated every 150 pixels. A feature will typically receive only one label, but this can cause confusion for long lines. Setting the label to repeat ensures that the line is always labeled locally.

Code¶

 1 * {
 2   stroke: red;
 3   label: [name];
 4   font-family: Arial;
 5   font-weight: bold;
 6   font-fill: black;
 7   font-size: 10;
 8   halo-color: white;
 9   halo-radius: 1;
10   label-follow-line: true;
11   label-max-angle-delta: 90;
12   label-max-displacement: 400;
13   label-repeat: 150;
14 }

Details¶

This example is similar to the Optimized label placement. The only differences are:

• The font family and weight have been specified

• In order to make the labels easier to read, a white “halo” has been added. The halo draws a thin 1 pixel white border around the text, making it stand out from the background.

Code¶

 1 [type = 'local-road'] {
 2   stroke: #009933;
 3   stroke-width: 2;
 4   z-index: 0;
 5 }
 6
 7 [type = 'secondary'] {
 8   stroke: #0055CC;
 9   stroke-width: 3;
10   z-index: 1;
11 }
12
13 [type = 'highway'] {
14   stroke: #FF0000;
15   stroke-width: 6;
16   z-index: 2;
17 }

Details¶

There are three types of road classes in our fictional country, ranging from back roads to high-speed freeways: “highway”, “secondary”, and “local-road”. In order to make sure the roads are rendered in the proper order of importance, a “z-index” attribute has been placed in each rule.

The three rules are designed as follows:

Lines 1-5 comprise the first rule, the filter matches all roads that the “type” attribute has a value of “local-road”. If this condition is true for a particular line, the rule renders it dark green, 2 pixels wide. All these lines are rendered first, and thus sit at the bottom of the final map.

Lines 7-11 match the “secondary” roads, painting them dark blue, 3 pixels wide. Given the “z-index” is 1, they are rendered after the local roads, but below the highways.

Lines 13-17 match the “highway” roads, painting them red 6 pixels wide. These roads are pained last, thus, on top of all others.

Code¶

 1 * {
 2   stroke: #009933;
 3 }
 4
 5 [@sd < 180M] {
 6   stroke-width: 6;
 7 }
 8
 9 [@sd > 180M] [@sd < 360M] {
10   stroke-width: 4;
11 }
12
13 [@sd > 360M] {
14   stroke-width: 2;
15 }

Details¶

It is often desirable to make shapes larger at higher zoom levels when creating a natural-looking map. This example varies the thickness of the lines according to the zoom level (or more accurately, scale denominator). Scale denominators refer to the scale of the map. A scale denominator of 10,000 means the map has a scale of 1:10,000 in the units of the map projection.

This style contains three rules. The three rules are designed as follows:

The order of these rules does not matter since the scales denominated in each rule do not overlap.

The first rule provides the stroke color used at all zoom levels, dark gray, while the other three rules cascade over it applying the different stroke widths based on the current zoom level leveraging the “@sd” pseudo attribute. The “@sd” pseudo attribute can only be compared using the “<” and “>” operators, using any other operator will result in errors.

The result of this style is that lines are drawn with larger widths as one zooms in and smaller widths as one zooms out.