telegraphic
commented
2 years ago Hi Furen,
It does appear pygdsm version of GSM16 returns small negative values. Jeff Zheng's original code does too (https://github.com/jeffzhen/gsm2016). Comparsion images shown below (they look the same!).
As this is an issue with the underlying GSM16 model, there's not much I can do. My suggestion would be to to just set all values less than zero to zero, or add in an offset.
pygdsm output
gsm16 output
The GlobalSkyModel2016 produce sky map with negative brightness temperature at several GHz to 100 GHz, which is not physical And the fraction of the pixels with negative is rather large (~30% for 50 GHz). It seems like that the negative values are present in the map data of GSM2016. Do you know how to deal with the issue? It seems like that the GSM08 model does not have that problem.