Attribute symbology

The attribute symbology tab supports the display of maps with the standard settings from depthmapX, plus other settings that are useful for the space syntax community. The default style is applied as soon as an attribute is selected in the “Numeric attributes” list. The user can then change the colour and data range settings to create a custom symbology that is more appropriate to the specific attribute. To see the result of the changed settings, the user needs to click “Apply Symbology”. This also stores the new settings with the QGIS project, and they become the style for that attribute. The user can flip between different attributes and they are displayed with their individual custom styles.

Colour settings

The colour settings include:

• “Colour range” – options for “classic” (default), “red-blue”, “greyscale” and “monochrome” display. The greyscale and monochrome colour ranges automatically use black or white lines depending on the darkness of the background colour;
• Invert – Inverts the range, assigning the top colour to the bottom values;
• Display order – Ensures that the top (default) or bottom values are displayed first in the map, the default being the red lines on top of all the others;
• Width / Size – Sets the line width or point size, which is constant in all styles except monochrome, where this value represents the maximum width/size.

Below are examples of the different colour range settings: classic (top), red-blue, greyscale and monochrome (bottom) with varying line width.

Other style parameters

The layers can have point, line or polygon features, and the colour settings are applied to all types of layers. The “Width / Size” parameter affects the size of points, the line width of lines, and the outline width of polygons. The size of points is by default 2.5, so that they are clearly visible, while the default line or outline width is 0.25. The outline of polygons is always black. In monochrome range, the polygons show a varying density hatch pattern.

Data range

The data range settings include:

• Interval number – sets the number of intervals in the colour range (default is 10, maximum is 1024);
• Interval type – selects the colour range interval distribution, with option for “Equal intervals” (default), “Quantiles”, “Natural breaks” (slower) and “Custom (Equal)”. The custom range unlocks the limits controls.
• Custom interval limits – the interval limits are by default the maximum (top) and minimum (bottom) values. With custom intervals the user can change the size of the top and bottom range, using a scale (bottom = 0 to top = 100) or the absolute value of the attribute. The other intervals in between are automatically calculated using equal intervals distribution. This setting is equivalent to the slider controls in the “Colour Range” settings of depthmapX.

Note:

The symbology applied to a layer can be further edited in the QGIS symbology dialog. These changes, however, are overridden by the “Attributes Explorer” module. The user should store any final display settings in a QGIS layer style file for later retrieval, or tweak the final display after finishing with thismodule.