An earlier topic in this forum explained that a noise level of -99 is used to indicate a NULL result, which can arise in many ways. Basically, it means that no noise level was calculated for that situation. A null result can be a problem when you want to include a particular receiver or contour point in a calculation. For example, you can't add or subtract the noise levels for two scenarios if one of the results is null.
NoiseMap 5.2 (currently in Beta) has functions that allow you to define how to treat a null result. In essence, an operation like:
60 dB + NULL = NULL; but
LOGSUM(R1,NULL) = R1
But the new COALESCE function lets you avoid NULL results: for example you can replace the NULL by an alternative result or by a defined value.
The Beta version is available for testing by established clients - please contact us for details.
