[R-sig-Geo] Cumulate space time data over days

[Edzer Pebesma]

On 07/17/2015 06:48 PM, pierluigi de rosa wrote:
> Dear all,
> 
> I'm have a simple question that I think should be easly to answer but I'm
> an R beginner anf I didn't find nothing exactly what I need.
> 
> I have a STFDF that register rainfall data over 14 years in 30 monitoring
> stations.
> I need to evaluate for each day the cumulative rainfall of the 3 days
> before (or 72 hours) and than extract data where this cumulative value is
> above a threshold.
> 
> How ca I reach that?

Since this is a pure time series problem, I'd try something along these
lines:

library(xts)
z = as(pioggieST1, "xts")
m = rollmean(z, 3, align = "right")
sel = m[apply(m > 300, 1, all),] # threshold 300

you may want to remove "any" with "all" if all stations should be above
the threshold of 300.

> Thanks
> 
> Summary of my data is below
> Thanks
> Pierluigi
> 
>> summary(pioggieST1)
> Object of class STFDF
>  with Dimensions (s, t, attr): (30, 8401, 1)
> [[Spatial:]]
> Object of class SpatialPointsDataFrame
> Coordinates:
>               min     max
> coords.x1 2272679 2320496
> coords.x2 4698989 4821088
> Is projected: TRUE
> proj4string :
> [+proj=tmerc +lat_0=0 +lon_0=15 +k=0.9996 +x_0=2520000 +y_0=0 +ellps=intl
> +units=m +no_defs]
> Number of points: 30
> Data attributes:
>                 nome
>  Allerona         : 1
>  Amelia           : 1
>  Attigliano       : 1
>  Avigliano_Umbro  : 1
>  Bastardo         : 1
>  Calvi_dell_Umbria: 1
>  (Other)          :24
> [[Temporal:]]
>      Index              timeIndex
>  Min.   :1991-01-01   Min.   :   1
>  1st Qu.:1996-10-01   1st Qu.:2101
>  Median :2002-07-02   Median :4201
>  Mean   :2002-07-02   Mean   :4201
>  3rd Qu.:2008-04-01   3rd Qu.:6301
>  Max.   :2013-12-31   Max.   :8401
> [[Data attributes:]]
>      values
>  Min.   :  0.000
>  1st Qu.:  0.000
>  Median :  0.000
>  Mean   :  1.489
>  3rd Qu.:  0.000
>  Max.   :273.000
> 
> 

-- 
Edzer Pebesma
Institute for Geoinformatics (ifgi),  University of Münster,
Heisenbergstraße 2, 48149 Münster, Germany; +49 251 83 33081
Journal of Statistical Software:   http://www.jstatsoft.org/
Computers & Geosciences:   http://elsevier.com/locate/cageo/
Spatial Statistics Society http://www.spatialstatistics.info

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