Area Along Vector

This plugin draws rectangle areas along polylines according to field values. It was developed in order to show car traffic volumes on a road network. Since a road has most often two ways, drawing a rectangle on each side, proportional to volume values, offered a good solution.

What does the plugin do?

For each vector of the vector layer, two rectangles are created: one on the right side for the forth value, the other on the left for the return value. Rectangles widths are proportional to values read from the selected fields (for example VOL and R_VOL). The resulting rectangles are stored in a new layer.

How does it work?

Select a vector layer with two fields containing back and forth values. Change parameters values to adjust rendering. Information of the minimum and maximum values to be drawn is displayed. User can thus adjust accordingly the minimum and maximum width of the rectangles. User can also set the limit under (over) which the minimum (maximum) width is always used. For example, if maximum limit is set to 500, all fields with values above 500 will be displayed with the same rectangle width (equal to the maximum limit width parameter).

A new shape file containing the rectangles is created and added to the canvas.