Consistency of the light level from place to place throughout the lighted area.
In an office it is important that there are no disturbing shadows falling on your desk. In a car park you don’t want to have dark corners.
To correctly measure the uniformity, you need to measure at every point on the grid (of the space) and determine the average light level.
When you divide the minimum light level that you have measured on the grid with the average light level, you get a number between 0 and 1. This number is communicated as the ‘Light Uniformity’ Uo. The lower the value, the more contrast you experience in the space.
To get a rough indication on the uniformity measure at key points of dedicated space.
Additionally, simply observe the area to see if there are a lot of shadows on the floor and walls or dark corners.
Good uniformity on floor > 0.4 Low light contrasts on floor
Poor uniformity on floor < 0.4 High light contrasts on floor