[R-sig-Geo] I: Interpolating snowfall values on a Digital Elevation Model
Stefano Sofia
stefano.sofia at regione.marche.it
Wed Feb 14 09:34:27 CET 2018
This is the contribute of Daniel Knitter to my previous doubts.
Thank you again to Daniel Knitter and Dominik Scheider for their help.
Stefano
(oo)
--oOO--( )--OOo----------------
Stefano Sofia PhD
Area Meteorologica e Area nivologica - Centro Funzionale
Servizio Protezione Civile - Regione Marche
Via del Colle Ameno 5
60126 Torrette di Ancona, Ancona
Uff: 071 806 7743
E-mail: stefano.sofia at regione.marche.it
---Oo---------oO----------------
________________________________________
Da: Daniel Knitter [knitter at geographie.uni-kiel.de]
Inviato: martedì 13 febbraio 2018 10.51
A: Stefano Sofia
Oggetto: Re: [R-sig-Geo] Interpolating snowfall values on a Digital Elevation Model
Dear Stefano,
concerning the error messages:
1) you need projected (metric) coordinates -- while you are using geographic ones
2) the extract function is from package raster and expects a raster input -- while you give a SpatialGridDataFrame as input
this code should work:
library(raster)
ita_DEM <- getData('alt', country='ITA', mask=TRUE)
ita_DEM <- projectRaster(ita_DEM, crs = CRS("+init=epsg:32633"))
## LOADING RAINFALL DATA
rain_data <- data.frame(cumulata=c(11.8, 9.0, 8.0, 36.6, 9.4),
Long_Cent=c(12.61874, 12.78690, 12.96756, 13.15599, 13.28157),
Lat_Cent=c(43.79447, 43.85185, 43.76267, 43.03470, 43.08003),
altitude=c(112.20, 42.93, 36.14, 747, 465))
library(sp)
coordinates(rain_data) <- ~Long_Cent+Lat_Cent
proj4string(rain_data) <- CRS("+init=epsg:4326")
rain_data <- spTransform(rain_data, CRS("+init=epsg:32633"))
rain_data$extractedelevationvalues <- extract(x=ita_DEM, y=rain_data)
newgrid <- as(ita_DEM, "SpatialGridDataFrame")
names(newgrid) <- "extractedelevationvalues"
library(automap)
RegressionKriging_snow <- autoKrige(cumulata~extractedelevationvalues,
rain_data,
newgrid)
Cheers,
Daniel
On Tue, 13 Feb 2018 08:45:34 +0000
Stefano Sofia <stefano.sofia at regione.marche.it> wrote:
> Dear Daniel and list users,
> I tried to follow the instructions but I encountered two kinds of errors.
> This is a reproducibile code:
>
> ---------------------------------------------------------------------------------------------------------------
> library(automap)
> library(ggplot2)
> library(gstat)
> library(raster)
> library(rasterVis)
> library(rgdal)
> library(maptools)
>
> ## LOADING DEM
> ita_DEM <- getData('alt', country='ITA', mask=TRUE)
> crs(ita_DEM) <- "+init=epsg:4326 +proj=longlat +datum=WGS84 +no_defs +ellps=WGS84 +towgs84=0,0,0"
> #ita_DEM <- as(ita_DEM, "SpatialGridDataFrame")
> str(ita_DEM)
>
> ## LOADING RAINFALL DATA
> rain_data <- data.frame(Cumulata=c(11.8, 9.0, 8.0, 36.6, 9.4), Long_Cent=c(12.61874, 12.78690, 12.96756, 13.15599, 13.28157), Lat_Cent=c(43.79447, 43.85185, 43.76267, 43.03470, 43.08003), Altitude=c(112.20, 42.93, 36.14, 747, 465))
>
> stations <- data.frame(rain_data$Long_Cent, rain_data$Lat_Cent)
> rain_data <- SpatialPointsDataFrame(stations, rain_data, proj4string=CRS("+init=epsg:4326"))
> stations <- SpatialPoints(stations, proj4string=CRS("+init=epsg:4326"))
>
> ## EXTRACT THE ELEVATION VALUES TO MY POINTS
> rain_data$ExtractedElevationValues <- extract(x=ita_DEM, y=stations)
>
> ## CREATE GRID FOR KRIGING OUTPUT
> minx <- rain_data at bbox[1,1]
> maxx <- rain_data at bbox[1,2]
> miny <- rain_data at bbox[2,1]
> maxy <- rain_data at bbox[2,2]
> pixel <- 0.01
> grd <- expand.grid(x=seq(minx, maxx, by=pixel), y=seq(miny, maxy, by=pixel))
> coordinates(grd) <- ~x+y
> gridded(grd) <- TRUE
> proj4string(grd) <- CRS("+init=epsg:4326")
>
> ## KRIGING: autoKrige(YourMeasurements ~ YourExtractedElevationValues, YourMeasurementLocations, TargetGrid)
> OK_snow <- autoKrige(Cumulata ~ rain_data$ExtractedElevationValues, rain_data, grd)
> -------------------------------------------------------------------------------------------------------------------------------
>
> The error I get is:
> Error in autoKrige(Cumulata ~ rain_data$ExtractedElevationValues, rain_data, :
> Either input_data or new_data is in LongLat, please reproject.
> input_data: +init=epsg:4326 +proj=longlat +datum=WGS84 +no_defs +ellps=WGS84 +towgs84=0,0,0
> new_data: +init=epsg:4326 +proj=longlat +datum=WGS84 +no_defs +ellps=WGS84 +towgs84=0,0,0
>
> but I did pay attention to have the same reference system in rain_data, drg and the Digital Elevation Model.
>
> Moreover, if I impose the class of the DEM to SpatialGridDataFrame when I extraxt the elevation points from the DEM I get the following error:
> Error in (function (classes, fdef, mtable) :
> unable to find an inherited method for function ‘extract’ for signature ‘"SpatialGridDataFrame", "SpatialPoints"’
> Calls: extract -> <Anonymous>
>
>
> Would you please somebody help to show me where is my mistake?
>
> Thank you for all your attention
> Stefano
>
> (oo)
> --oOO--( )--OOo----------------
> Stefano Sofia PhD
> Area Meteorologica e Area nivologica - Centro Funzionale
> Servizio Protezione Civile - Regione Marche
> Via del Colle Ameno 5
> 60126 Torrette di Ancona, Ancona
> Uff: 071 806 7743
> E-mail: stefano.sofia at regione.marche.it
> ---Oo---------oO----------------
> ________________________________________
> Da: R-sig-Geo [r-sig-geo-bounces at r-project.org] per conto di Daniel Knitter [knitter at geographie.uni-kiel.de]
> Inviato: lunedì 12 febbraio 2018 9.16
> A: r-sig-geo at r-project.org
> Oggetto: Re: [R-sig-Geo] Interpolating snowfall values on a Digital Elevation Model
>
> ...sorry, I missed one step: you need to extract the elevation values to your points via extract function from the raster package:
>
> YourPoints$YourExtractedElevationValues <- extract(x = DEM, y = YourPoints)
>
> autoKrige(YourMeasurements ~ YourExtractedElevationValues, YourMeasurementLocations, TargetGrid)
>
>
> Sorry for spamming.
>
> Best,
> Daniel
>
> On Mon, 12 Feb 2018 08:03:41 +0000
> Stefano Sofia <stefano.sofia at regione.marche.it> wrote:
>
> > Dear list users,
> > I have to produce rainfall maps. I know how to create a (bi-dimensional) grid and interpolate rainfall values (from automatic rain gauges) on that grid using Kriging:
> >
> > myinterpolation <- autoKrige(myrainfall_cumulate ~ 1, rain_data_UTM, mygrid)
> >
> > In reality I am dealing with snowfall values on mountain regions, and in this case altitude is an important factor, the use of a Digital Elevation Model might make the difference.
> > Looking in the web I found some important material about accessing elevation data in R with the "elevatr" package (by J.W.Hollister), I am reading it.
> > My concern would then be to interpolate snowfall values on a Digital Elevation Model. Did somebody already use R for these kinds of calculations? Could somebody share with me some useful hints?
> >
> > Thank you for your attention
> > Stefano Sofia
> >
> >
> > (oo)
> > --oOO--( )--OOo----------------
> > Stefano Sofia PhD
> > Area Meteorologica e Area nivologica - Centro Funzionale
> > Servizio Protezione Civile - Regione Marche
> > Via del Colle Ameno 5
> > 60126 Torrette di Ancona, Ancona
> > Uff: 071 806 7743
> > E-mail: stefano.sofia at regione.marche.it
> > ---Oo---------oO----------------
> >
> > ________________________________
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> Dr. Daniel Knitter
> CRC1266 -- Scales of Transformation
> Project A2 "Integrative Modeling of Socio-Environmental Dynamics"
>
> Christian-Albrechts-Universität zu Kiel
> Department of Geography
> Physical Geography -- Landscape Ecology and Geoinformation
> Ludewig-Meyn-Str. 14, room 109
> D - 24118 Kiel, Germany
>
> Phone: +49 431 880 2941
> Email: knitter at geographie.uni-kiel.de
>
> ________________________________
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> AVVISO IMPORTANTE: Questo messaggio di posta elettronica può contenere informazioni confidenziali, pertanto è destinato solo a persone autorizzate alla ricezione. I messaggi di posta elettronica per i client di Regione Marche possono contenere informazioni confidenziali e con privilegi legali. Se non si è il destinatario specificato, non leggere, copiare, inoltrare o archiviare questo messaggio. Se si è ricevuto questo messaggio per errore, inoltrarlo al mittente ed eliminarlo completamente dal sistema del proprio computer. Ai sensi dell’art. 6 della DGR n. 1394/2008 si segnala che, in caso di necessità ed urgenza, la risposta al presente messaggio di posta elettronica può essere visionata da persone estranee al destinatario.
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Dr. Daniel Knitter
CRC1266 -- Scales of Transformation
Project A2 "Integrative Modeling of Socio-Environmental Dynamics"
Christian-Albrechts-Universität zu Kiel
Department of Geography
Physical Geography -- Landscape Ecology and Geoinformation
Ludewig-Meyn-Str. 14, room 109
D - 24118 Kiel, Germany
Phone: +49 431 880 2941
Email: knitter at geographie.uni-kiel.de
________________________________
AVVISO IMPORTANTE: Questo messaggio di posta elettronica può contenere informazioni confidenziali, pertanto è destinato solo a persone autorizzate alla ricezione. I messaggi di posta elettronica per i client di Regione Marche possono contenere informazioni confidenziali e con privilegi legali. Se non si è il destinatario specificato, non leggere, copiare, inoltrare o archiviare questo messaggio. Se si è ricevuto questo messaggio per errore, inoltrarlo al mittente ed eliminarlo completamente dal sistema del proprio computer. Ai sensi dell’art. 6 della DGR n. 1394/2008 si segnala che, in caso di necessità ed urgenza, la risposta al presente messaggio di posta elettronica può essere visionata da persone estranee al destinatario.
IMPORTANT NOTICE: This e-mail message is intended to be received only by persons entitled to receive the confidential information it may contain. E-mail messages to clients of Regione Marche may contain information that is confidential and legally privileged. Please do not read, copy, forward, or store this message unless you are an intended recipient of it. If you have received this message in error, please forward it to the sender and delete it completely from your computer system.
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