Negative dB levels when generating Noise from Source #758
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I'm using NoiseModelling 5.0 to model alert sirens. I have extracted an area using the GeoClimate tool. I had to rename one of the fields in the output geojson from HEIGHT_WALL to HEIGHT in order to create the Delaunay Grid (kept giving me errors about not being able to find the HEIGHT column). I've set up my Noise_level_from_source, but when I output the Receivers_Level table,, I get the following: The input siren is 10m above the ground and 126dB in the LWD1000 (I don't have the full harmonics). The building the siren is situated on has a height of 8.5m, so I don't think it's because it's "Inside" a building. I've also tried moving the siren to an area with no buildings to see if that would help and still only get negative values. I'm 90% sure this is user error somewhere, but can't seem to figure it out. I can provide more input data if needed. |
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Replies: 2 comments 3 replies
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Hello, This field has been renamed to HZ1000 in NoiseModelling 5.0 You don't have to update the field name if you specify the field name in the parameter frequencyFieldPrepend in the WPS script (to LW ) |
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Yup, this did I. I saw the change in the documentation, but my brain just didn't key in on that being the issue for whatever reason. Thanks. I greatly appreciate the help. |
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As a side note, the negative value are the attenuation to apply to the emission value ex: -54.25 -> 126-54.25 = 71.75 dB |
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Hi Nicolas Noisemodelling 5.0.0. WPSBuilder, Resulting RECEIVERS_LEVEL Attribute Table
Info: With our old data structure (Fieldname LWD500) the suggestion with the parameter frequencyFieldPrepend in the WPS script to LW did not work |
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If you are using the source_geom table and you have Day Evening Night values it is HZD HZN as explained here: If you are using SOURCES_EMISSION table it is PERIOD, HZ columns: https://noisemodelling.readthedocs.io/en/latest/Input_source.html#sources-emission-table-definition |
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Hello,
This field has been renamed to HZ1000 in NoiseModelling 5.0
You don't have to update the field name if you specify the field name in the parameter frequencyFieldPrepend in the WPS script (to LW )