Hi all, Now the 6S parameters are complete, but the output map contains only NULLs, no matter what combinations of input parameters and flags I use. Have anyone encountered the same issue? (Info below.)
Thanks again. Zofie ---------------------------------------- Version: g.version -g version=7.4.0RC1 date=2017 revision=exported build_date=2017-11-18 build_platform=x86_64-pc-linux-gnu build_off_t_size=8 ---------------------------------------- Region: g.region -p projection: 1 (UTM) zone: 33 datum: etrs89 ellipsoid: grs80 north: 6653695 south: 6643685 west: 256495 east: 266505 nsres: 10 ewres: 10 rows: 1001 cols: 1001 cells: 1002001 ---------------------------------------- Input data: Sentinel2 L1C product B02 (tried with B01 too) r.info map=test_B02@p_Sentinel4Nature_S2_Oslo +----------------------------------------------------------------------------+ | Map: test_B02@p_Sentinel4Nat Date: Wed Dec 6 12:06:39 2017 | Mapset: p_Sentinel4Nature_S2_Oslo Login of Creator: stefan.blumentr | Location: ETRS_33N | DataBase: /data/grass | Title: S2A_OPER_PRD_MSIL1C_PDMC_20160907T044118_R008_V20160905T104022_2 | Timestamp: none |----------------------------------------------------------------------------| | | Type of Map: raster Number of Categories: 0 | Data Type: CELL | Rows: 1001 | Columns: 1001 | Total Cells: 1002001 | Projection: UTM (zone 33) | N: 6653695 S: 6643685 Res: 10 | E: 266505 W: 256495 Res: 10 | Range of data: min = 1 max = 28000 | | Data Description: | generated by r.in.gdal +----------------------------------------------------------------------------+ ---------------------------------------- 6s file: 25 - geometrical conditions=Sentinel-2A 9 5 10.6728 10.73413 59.90647 - month day hh.ddd longitude latitude 4 - atmospheric model=subarctic summer 3 - aerosol model=urban 50 - visibility [km] (aerosol model concentration) (this is estimated, I also tried with AOD specified) -0.055 - mean target elevation above sea level [km] -1000 - sensor height 166 - Sentinel2A Blue band B2 (440nm - 535nm) ---------------------------------------- Command: i.atcorr input=test_B02@p_Sentinel4Nature_S2_Oslo range=1,28000 elevation=dem_10m_25833@p_Sentinel4Nature_S2_Oslo parameters=/home/ NINA.NO/zofie.cimburova/Sentinel4Nature/DATA/6s.txt output=test_B02_atcorr >Atmospheric correction... >Atmospheric correction complete. (I am not sure about the range parameter, tried with 0,255 too. The DEM contains no NULLs. Also tried running with -r and -a flags.) ---------------------------------------- Output: r.info map=test_B02_atcorr@p_Sentinel4Nature_S2_Oslo +----------------------------------------------------------------------------+ | Map: test_B02_atcorr@p_Sentinel4N Date: Mon Dec 18 13:10:14 2017 | Mapset: p_Sentinel4Nature_S2_Oslo Login of Creator: zofie.cimburova | Location: ETRS_33N | DataBase: /data/grass | Title: test_B02_atcorr2 | Timestamp: none |----------------------------------------------------------------------------| | | Type of Map: raster Number of Categories: 0 | Data Type: FCELL | Rows: 1001 | Columns: 1001 | Total Cells: 1002001 | Projection: UTM (zone 33) | N: 6653695 S: 6643685 Res: 10 | E: 266505 W: 256495 Res: 10 | Range of data: min = -nan max = -nan | | Data Description: | generated by i.atcorr | | Comments: | i.atcorr input="test_B02@p_Sentinel4Nature_S2_Oslo" range=1,28\ | 000 elevation="dem_10m_25833@p_Sentinel4Nature_S2_Oslo" para\ | meters="/home/NINA.NO/zofie.cimburova/Sentinel4Nature/DATA/6s.txt" o\ | utput="test_B02_atcorr2" rescale=0,255 | +----------------------------------------------------------------------------+ On Fri, Dec 15, 2017 at 5:12 PM, Žofie Cimburová <zoficimbur...@gmail.com> wrote: > Dear Markus, > thanks for your reply, this is exactly what I need to know! > > Best, Zofie > > On Fri, Dec 15, 2017 at 5:09 PM, Markus Neteler <nete...@osgeo.org> wrote: > >> >> On Dec 15, 2017 3:54 PM, "Žofie Cimburová" <zoficimbur...@gmail.com> >> wrote: >> > >> > Dear all, >> > I am trying to use i.atcorr (GRASS 7.4) to apply atmospheric >> corrections for Sentinel 2 data. The documentation provides a great help, >> but there are two points I am not sure about - >> > >> > - I don't need the atmospheric correction to be applied to the whole >> scene, so I only imported a small clip of the scene to GRASS. What >> longitude and latitude shall I then specify in the 6S parameters? >> >> I'd use the center coordinates of the clipped area. >> >> > Or is it necessary to apply the corrections to the entire scene? >> >> No since it is a pixel based algorithm. >> >> > - How can I estimate the value of visibility (aerosol model >> concentration)? >> >> There are AERONET data online somewhere which might be the best choice. >> >> Markus >> > >
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