IES Flood Report Axial Display

The Axial Display tab allows you to view a Cartesian or Polar graph of the luminaire's axial candela distribution. You can toggle between Cartesian or Polar graphs using the Display Type radio buttons.

Axis

This section allows you to specify which axes are displayed and their corresponding color. By default, the horizontal axis is shown in Red and the vertical axis in Blue.

Display Type

This section displays the axial candela values using a Cartesian graph or Polar graph.

Polar Graph - The polar diagram is divided into four rings, each representing a 25% increase in magnitude. At the center of the polar diagram, the candela intensity equals 0. At the outer ring, the candela intensity equals the maximum candela value. The inner ring represents 25% of the maximum value, the second ring 50% of the maximum, and the third ring 75% of the maximum.  As the candela values increase in magnitude (increase in intensity) they move towards the outer portions of the polar diagram.

Radiating along the diagram are angular increment lines - each representing a 10 degree angle increment. By following the angular increments to the horizontal cone or vertical slice, it is easy to approximate the candela value for any location on the polar plot.

Cartesian Graph - The Cartesian graph is divided into grids along the X and Y axis. The X axis is hatched by vertical grid lines, each representing 30 degree increments. The vertical line at the center of the Cartesian axis represents the 0 degree plane The Y axis is hatched by horizontal grid lines, each representing a 25% increase in magnitude of candlepower. The topmost horizontal line represents the maximum candela value (or maximum scaling value). Both horizontal and vertical distributions may be read in the Cartesian graph by plotting their locations relative to the nearest grid line.

More information is provided in the Photometry 101 topic.

Scaling

The scale for both display types is controlled by the overall maximum candela value. You may change the plot scale easily by simply entering a different candela value to be used as the plot extents.

Hint: Using a consistent plot scale across multiple photometric files allows you to compare light distributions for these files on a consistent and equal basis.