NoiseMap Forums

NoiseMap Software => Support => Topic started by: roger on October 16, 2017, 02:48:31 PM

Title: Why do I get -99 dB for all my results?
Post by: roger on October 16, 2017, 02:48:31 PM

Missing results are shown as -99.  This indicates that no noise level has been calculated for that case.  This can happen in many ways, for example:

• A tile was not calculated
• The receiver point was outside the angle of view or beyond the cut-off distance
• The receiver point was inside a building
• There were no noise sources of the type applicable to the chosen calculation

Your case was the last of these - you wanted to calculate the Leq of rail noise sources, but chose the CRTN calculation method.
Each calculation method is applicable to its own type of source:

• CRTN for Roads
• CRN & TNPM for Rail
• BS5228 for Open sites

Please beware that choosing Leq calculations will NOT calculate noise for all types of source.
Please also beware that the choosing a category combination like Road + Rail does not (and cannot) add together noise from road and rail sources. 

Adding noise from different types of noise source
To do this, you must

• firstly calculate the road sources using CRTN and the rail sources using CRN or TNPM; and then
  
• use the Results Processor to add together the noise from the two types of noise source