Samenvatting
In the past, the manner used for the illumination of large areas was dependent on the possibilities to reach the light sources in view of maintenance. Their height was held relatively low. Since high masts appeared on the market, which permits to lower the floodlights down to working height, the lighting technique evolved. It now often happens that the light sources are situated over the fog layer. The paper analysis the effect on visibility, illuminance and luminance resulting from such a situation.