Band name order - Band_List vs bandIds

s2tbx
#1

Hi,

In most cases, XML files refer to bands by bandIs. In the granule files, lines like these tell me that B8A has bandId=8:

<MASK_FILENAME bandId="8" type="MSK_DEFECT">S2A_OPER_MSK_DEFECT_SGS__20160123T093126_A003061_T47NNJ_B8A_MSIL1C.gml</MASK_FILENAME>

So the order of the bands that bandIds refer to is B1, ..., B8, B8A, B9, ..., B12.

However, the top asset XML file contains this:
<Band_List>
<BAND_NAME>B1</BAND_NAME>
<BAND_NAME>B2</BAND_NAME>
<BAND_NAME>B3</BAND_NAME>
<BAND_NAME>B4</BAND_NAME>
<BAND_NAME>B5</BAND_NAME>
<BAND_NAME>B6</BAND_NAME>
<BAND_NAME>B7</BAND_NAME>
<BAND_NAME>B8</BAND_NAME>
<BAND_NAME>B9</BAND_NAME>
<BAND_NAME>B10</BAND_NAME>
<BAND_NAME>B11</BAND_NAME>
<BAND_NAME>B12</BAND_NAME>
<BAND_NAME>B8A</BAND_NAME>
</Band_List>

So B8A is at the end. What is the purpose of this list? The same file contains bandIds for SOLAR_IRRADIANCE without band names, and without knowing the correct order of bands (with B8A presumably last), I would have assigned the values of SOLAR_IRRADIANCE incorrectly - so this discrepancy is confusing.

#2

By the way, the granule XML metadata in the spec are wrong, because they refer to B00, which does not exist, and they don’t mention B8A.

#3

Hello Simon,

The list contains all the Bands that are in the downloaded product. If you were to specify the Bands you require, then the product XML (at the top level, inside the SAFE folder) would contain just these Bands.

As to why the B8A is at the end of the list; perhaps this is just the way that XML treats the input information. You’ll note that the ‘double digit Bands’ start with 1 (B10, B11 and B12), so - in my reasoning - the B8A, having a first numeric of 8 (rather than 1) would be after these in the list.

I’ll look into the issue with the [PSD]

Cheers

Jan

S2 MPC Operations Manager

#4

Thank you for the explanation, Jan!

#5

So, does this mean that BandId 0 in Solar Irradiance is Band 1 in reality? and that BandId 12 is Band 8a? Thank you.