Chapter 6. Working With Styles

Point styles can be customized in many ways. The Size slider and box control the total size of the point item. Due to variations in particular symbol drawing techniques and different visual weights (which affect apparent size), it is often the case that symbols with the same size are similar, but not identical in size or area. This is to be expected. We have tried to keep the sizes consistent for all symbols created directly inside of Cartographica, but you may need to balance sizes a bit, especially when using custom picture- or font-based symbols or when using symbols of greatly differing weights.

For most Point symbols, the Stroke box and color well determine if the outline of the symbol is visible and the color of the symbol outline. Not surprisingly, the Fill color well determines the color which fills in the symbol. For some symbols, there is no "fill" area, and therefore the symbol's fill color does not matter and the stroke must be present for the symbol to draw. Examples of these in the built-in symbols are the cross and plus.

Although Cartographica may not ship with the variety of symbols of some other programs, the ability to import high-resolution symbols from a variety of places makes up for many missing symbols. To change a symbol, the Symbol Well is used as the dropping point for one of a variety of sources:

Besides symbols, Cartographica can also represent points with a picture stored on disk by using the Picture check box and field selector and optionally the Picture Path to specify the location of the referenced pictures. When using a picture to represent the points on the map, the Picture box must be selected and a field must be chosen in the pop-up menu. The picture field designates which column contains the file name of the referenced file, which can be a full or partial path name. A partial path name is resolved first by looking at the Picture Path and then by using the directory the layer (or map set for an internally-stored layer) is saved in as the default. When using a picture symbol, the Image Viewer will come up whenever a represented point is selected, showing a larger version of the picture (or a playable version of the movie, if the referenced data is a movie file).

Figure 6.3. Symbol Browser Window

Labels may also be added to point features, see Section 6.1.4, “Labeling Features” for further information.

Line styles can be used to change the visual aspects of lines on a map. Some of the components for line styles should now be familiar to you, based on the point styles, but lines have some additional attributes.

Line styles are based on a line style template, which are dropped into the line style well in order to assign them to a style. In the example shown below, the Default Style for this line contains a line with thin black strokes, and a yellow fill. Not all lines will have both parameters, however they should all have a Stroke color, so that you can change the overall color of the line style. In some special cases, there are colors in the style that are not able to be changed through this window. If you are using one of these styles and find the need to change the color, look for another line style in the Lines tab of the Uber Browser.

The Width determines the width of the line, and in the case of a stroked line, the width of the stroke as well. The two are proportionate, and therefore the width is a scaling factor that operates equally on each of the components of the line.

Figure 6.4. Style Window (displaying a complex line style)

Polygon styles can be used to change the coloring, pattern, outline style, and labeling of polygon features on the map. You can leverage much of your knowledge from the line and point styles to use the polygon style window. In fact, the window is even set up to reflect this, with the Outline box in the top position (where the Line box appears for lines), and the Pattern box in the lower position (where the symbol box appears for poings).

When a polygon is drawn, Cartographica uses the Outline information to draw the outline of the polygon, and the Pattern information to fill in the inside of the polygon.

The patterns in Cartographica work similarly to the Symbols in point layers. There are certain pre-defined patterns that come with Cartographica, and they are made up of black and transparent data, so that they can be scaled and colored easily. However, you can also use just about any image (including symbols from the symbol tab) as fill for polygon layers.

When a pattern is not in use, the pattern well is empty (as is shown below), and there is a Fill color well to determine the solid fill color to be used. When patterns are used, the pattern will appear in the pattern well and Stroke and Size controls will be added, to control the color of the stroke, and the pattern size, respectively.

Figure 6.5. Style Window (displaying a complex polygon style)

All styles can be labeled, providing a way to indicate the name or other attributes of a feature on the map.

Labels are among the most complex options in Cartographica due especially to the need to avoid clutter and collision when items are placed near each other. Although the particular algorithm cannot be described in detail and is subject to some amount of change, here are some important points to understand about how Cartographica handles labels:

Labels are controlled by the content of the Item Label box, shown in close-up in Figure 6.6, “Label field”. Labels can contain text and fields and can be styles using one or more fonts and sizes. The example shown here is a simple label containing introductory text "Zip:" and the contents of the ZIP_CODE field. In the Item Label box, the contents of a field are represented by a Field Marker, which is the name of the field surrounded by a colored oval.

Field Markers may be moved around through drag and drop and may be copied, pasted, and deleted.

Figure 6.6. Label field

So far, we have been describing simple styles, which apply identically to every feature in a layer. However, it is often the case that some features in a layer deserve special attention. Examples of this include a layer that contains cities, some of which are state or country capitals, or a layer of roads that contains both local roads and large highways. In each of these cases, some of the features in the layer are singled out for special attention.

Complex Styles are also used when attempting to show quantitative or qualitative attribute information graphically. For example, a polygon layer representing states could be colored differently based on population; similarly, the size of a city symbol in a point layer could vary based on population.

There are three primary controls for complex styles: the Based on: pop-up menu, which is used to determine which field is used to discriminate between the styles; the style list on the left side of the window above the Preview box, which displays the list of defined styles and provides for addition, deletion, etc.; and the Hide features that don't match check box, which determines whether the Default Style is used.

In complex styles, the Based on: pop-up menu determines which column of data is to be used for discriminating between the styles. Once the column is selected, use the table on the left of the window to determine the breaks for each style variant.

When using a string column to discriminate, you must use the Value column, which indicates an exact match between the value in the column and the one you define in the style here. When using a numeric column to discriminate, you may use either the Value column or the From and To columns. For the Value column, the data must still match exactly. When using the From and To columns, the value must be within the range specified. The Distribute button may be used to help create natural ranges based on a linear distribution over the range of the data in the selected layer.

Under Based on are 3 pieces of data that appear when a column name is selected. These are the field type (string, number, date), and the minimum and maximum values.

The table in the left of the window lists the values or ranges for each style in the style set. To change the appearance of the style, select it in the table at the left and then adjust the parameters on the right, using the techniques described previously for each feature type.

You may also select multiple styles at the same time, allowing simultaneous editing of items. This is useful, for example, when using different symbols, but wanting to change the size for each of them. In this case, select the desired styles and then change the size. The size will change, but the remainder of the appearance will remain unchanged.

Styles are added to the list by using the + and - buttons, or by Edit  >  Duplicate or Edit  >  Duplicate and Increment. The + button adds a new style by copying the default style. Each of the menu items provides a way to add an identical copy of the selected style to the list, with the Duplicate and Increment also increasing the From and To values.

When using quantitative information to discriminate between styles, it is often beneficial to have Cartographica assign breaks between the styles. The gear menu provides access to these functions, as outlined below:

All style information updates immediately, both in the preview window and in the map view, so the user should be able to drag the sliders and move around with the color picker until they have matched what they need.