Re: [GRASS-user] Sentinel2- flooding
Great - thanks all. I'll let you know how I get on. Thanks On Sath 8 Noll 2018 at 12:09, Markus Neteler wrote: > On Fri, Dec 7, 2018 at 8:14 PM Stefan Blumentrath > wrote: > > > > Hi Shane, > > > > Following up on robertos answer: > > > > You could try the Normalized Difference Water Index (NDWI) which is > computed for S-2 as: > > > > ndwi = (B08-B11)/(B08+B11) > > > > or alternatively > > > > ndwi = (B03 - B08) / (B03 + B08) > > > > See e.g.: > https://github.com/sentinel-hub/custom-scripts/blob/master/sentinel-2/ndwi/script.js > > ... or just adapt the bands here: > > https://grass.osgeo.org/grass74/manuals/i.vi.html#calculation-of-ndvi > > > You could also take a look at Sentinel-1 for flooding / water bodies. > However, Sentinel-1 would have to be pre-processed in SNAP/gpt. > > Yes, Sentinel-1 is probably more relevant when it comes to > identification of flooded areas. > > Markus > -- Le gach dea ghui, *Shane Carey* *GIS and Data Solutions Consultant* ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Sentinel2- flooding
On Fri, Dec 7, 2018 at 8:14 PM Stefan Blumentrath wrote: > > Hi Shane, > > Following up on robertos answer: > > You could try the Normalized Difference Water Index (NDWI) which is computed > for S-2 as: > > ndwi = (B08-B11)/(B08+B11) > > or alternatively > > ndwi = (B03 - B08) / (B03 + B08) > > See e.g.: > https://github.com/sentinel-hub/custom-scripts/blob/master/sentinel-2/ndwi/script.js ... or just adapt the bands here: https://grass.osgeo.org/grass74/manuals/i.vi.html#calculation-of-ndvi > You could also take a look at Sentinel-1 for flooding / water bodies. > However, Sentinel-1 would have to be pre-processed in SNAP/gpt. Yes, Sentinel-1 is probably more relevant when it comes to identification of flooded areas. Markus ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Sentinel2- flooding
Great thanks On Aoine 7 Noll 2018 at 19:14, Stefan Blumentrath < stefan.blumentr...@nina.no> wrote: > Hi Shane, > > > > Following up on robertos answer: > > You could try the Normalized Difference Water Index (NDWI) which is > computed for S-2 as: > > ndwi = (B08-B11)/(B08+B11) > > or alternatively > > ndwi = (B03 - B08) / (B03 + B08) > > See e.g.: > https://github.com/sentinel-hub/custom-scripts/blob/master/sentinel-2/ndwi/script.js > > > > You could also take a look at Sentinel-1 for flooding / water bodies. > However, Sentinel-1 would have to be pre-processed in SNAP/gpt. > > > > Cheers > > Stefan > > > > *From:* grass-user *On Behalf Of *Shane > Carey > *Sent:* fredag 7. desember 2018 17:35 > *To:* roberto.marzoc...@gmail.com > *Cc:* grass-user grass-user > *Subject:* Re: [GRASS-user] Sentinel2- flooding > > > > Ok, thanks. > > Le gach dea ghui, > > *Shane Carey* > > *GIS and Data Solutions Consultant* > > > > > > On Fri, Dec 7, 2018 at 2:45 PM Roberto Marzocchi < > roberto.marzoc...@gmail.com> wrote: > > I Think there isn't any tool pre-configured. You need to find an index to > calculate "flooded" cells and then you can simply use r.mapcalc > > > > R > > > > Il giorno ven 7 dic 2018 alle ore 14:45 Shane Carey > ha scritto: > > Hi, > > > > I've obtained an image from sentinel2 where it shows flooding. Just > wondering are there tools in Grass to classify an image in order to pull > out these "flooded" pixels? > > > > Thanks > > -- > > Le gach dea ghui, > > *Shane Carey* > > *GIS and Data Solutions Consultant* > > ___ > grass-user mailing list > grass-user@lists.osgeo.org > https://lists.osgeo.org/mailman/listinfo/grass-user > > -- Le gach dea ghui, *Shane Carey* *GIS and Data Solutions Consultant* ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Sentinel2- flooding
Hi Shane, Following up on robertos answer: You could try the Normalized Difference Water Index (NDWI) which is computed for S-2 as: ndwi = (B08-B11)/(B08+B11) or alternatively ndwi = (B03 - B08) / (B03 + B08) See e.g.: https://github.com/sentinel-hub/custom-scripts/blob/master/sentinel-2/ndwi/script.js You could also take a look at Sentinel-1 for flooding / water bodies. However, Sentinel-1 would have to be pre-processed in SNAP/gpt. Cheers Stefan From: grass-user On Behalf Of Shane Carey Sent: fredag 7. desember 2018 17:35 To: roberto.marzoc...@gmail.com Cc: grass-user grass-user Subject: Re: [GRASS-user] Sentinel2- flooding Ok, thanks. Le gach dea ghui, Shane Carey GIS and Data Solutions Consultant On Fri, Dec 7, 2018 at 2:45 PM Roberto Marzocchi mailto:roberto.marzoc...@gmail.com>> wrote: I Think there isn't any tool pre-configured. You need to find an index to calculate "flooded" cells and then you can simply use r.mapcalc R Il giorno ven 7 dic 2018 alle ore 14:45 Shane Carey mailto:careys...@gmail.com>> ha scritto: Hi, I've obtained an image from sentinel2 where it shows flooding. Just wondering are there tools in Grass to classify an image in order to pull out these "flooded" pixels? Thanks -- Le gach dea ghui, Shane Carey GIS and Data Solutions Consultant ___ grass-user mailing list grass-user@lists.osgeo.org<mailto:grass-user@lists.osgeo.org> https://lists.osgeo.org/mailman/listinfo/grass-user ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Sentinel2- flooding
Ok, thanks. Le gach dea ghui, *Shane Carey* *GIS and Data Solutions Consultant* On Fri, Dec 7, 2018 at 2:45 PM Roberto Marzocchi < roberto.marzoc...@gmail.com> wrote: > I Think there isn't any tool pre-configured. You need to find an index to > calculate "flooded" cells and then you can simply use r.mapcalc > > R > > Il giorno ven 7 dic 2018 alle ore 14:45 Shane Carey > ha scritto: > >> Hi, >> >> I've obtained an image from sentinel2 where it shows flooding. Just >> wondering are there tools in Grass to classify an image in order to pull >> out these "flooded" pixels? >> >> Thanks >> -- >> Le gach dea ghui, >> *Shane Carey* >> *GIS and Data Solutions Consultant* >> ___ >> grass-user mailing list >> grass-user@lists.osgeo.org >> https://lists.osgeo.org/mailman/listinfo/grass-user > > ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] Sentinel2- flooding
I Think there isn't any tool pre-configured. You need to find an index to calculate "flooded" cells and then you can simply use r.mapcalc R Il giorno ven 7 dic 2018 alle ore 14:45 Shane Carey ha scritto: > Hi, > > I've obtained an image from sentinel2 where it shows flooding. Just > wondering are there tools in Grass to classify an image in order to pull > out these "flooded" pixels? > > Thanks > -- > Le gach dea ghui, > *Shane Carey* > *GIS and Data Solutions Consultant* > ___ > grass-user mailing list > grass-user@lists.osgeo.org > https://lists.osgeo.org/mailman/listinfo/grass-user ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
[GRASS-user] Sentinel2- flooding
Hi, I've obtained an image from sentinel2 where it shows flooding. Just wondering are there tools in Grass to classify an image in order to pull out these "flooded" pixels? Thanks -- Le gach dea ghui, *Shane Carey* *GIS and Data Solutions Consultant* ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
