Re: [R-sig-Geo] regression-kriging and co-kriging (Edzer Pebesma)
On 8/15/19 12:31 PM, Emanuele Barca wrote:
> Dear Edzer,
>
> sorry for bothering you once more but I need to be sure about my R script.
>
> In summary, i'm comparing the performance of regression-kriging and
> collocated co-kriging.
>
> Regression-kriging was based on an unique covariate, the elevation Z.
>
> I use Z as unique ancillary variable in the Co-kriging.
>
> As first attempt, the final raster maps were completely different. It
> appeared that it was due
>
> to the fact that the dataset was non-stationary and only
> regression-kriging overcomes this issue, while co-kriging not.
>
> But if I pass to universal co-kriging introducing Z as covariate, it
> bacomes useless as ancillary variable!
>
> What is my mistake?
You assume that someone else can be sure about your analysis by looking
at your R script without having access to your data.
And you are starting a personal dialogue on a list, essentially
uninviting everyone else to get involved.
>
> emanuele
>
>
>
>
> Il 2019-08-15 12:00 r-sig-geo-requ...@r-project.org ha scritto:
>> Send R-sig-Geo mailing list submissions to
>> r-sig-geo@r-project.org
>>
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>> or, via email, send a message with subject or body 'help' to
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>>
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>>
>> When replying, please edit your Subject line so it is more specific
>> than "Re: Contents of R-sig-Geo digest..."
>>
>>
>> Today's Topics:
>>
>> 1. Error running codes (Enoch Gyamfi Ampadu)
>> 2. Re: regression-kriging and co-kriging (Edzer Pebesma)
>>
>> --
>>
>> Message: 1
>> Date: Thu, 15 Aug 2019 06:51:49 +0200
>> From: Enoch Gyamfi Ampadu
>> To: r-sig-geo@r-project.org
>> Subject: [R-sig-Geo] Error running codes
>> Message-ID:
>>
>> Content-Type: text/plain; charset="utf-8"
>>
>> Dear List,
>>
>> Please I have been running a certain the codes below to read my image,
>> shapeffile to enable me classify for cover with Random forest. I have
>> gotten to the point of extracting the raster values and the raster
>> information. However I keep getting errors. though I have tried different
>> combination and other codes like readOGR for importing the training
>> polygon. I will be glad if you could be of help as I am new to using R.
>>
>> #import clip image of study area
>>
>> TestImg3 <- brick("C:\\Users\\hp\\Desktop\\Data collection\\Nkandla
>> Images\\Landsat\\2019\\08052019\\Corrected\\New
>> Folder\\Image08052019_Clip.tif")
>>
>> #Assign name of bands
>> names(TestImg3) <- c(paste0("B", 1:7, coll=""), "B9")
>> plotRGB(TestImg3, r=4, g=3, b=2, stretch ="lin")
>>
>> #Import training shapefile
>> sample <- shapefile("C:/Users/hp/Desktop/Data collection/Nkandla
>> Images/Landsat/2019/08052019/Corrected/Train08052019_2.shp")
>>
>> responseCol <- "class"
>>
>> #(I have tried options of changing "class" to "classname" as reflect
>> actaul
>> name assigned in ArcMap)
>>
>> # Overlap the sample polygons on the image (combine the class information
>> with extracted values).
>>
>> pixels = data.frame(matrix(vector(), nrow = 0, ncol =
>> length(names(img)) +
>> 1))
>> for (i in 1:length(unique(sample[[responseCol]]))){
>> category <- unique(sample[[responseCol]])[i]
>> categorymap <- sample[sample[[responseCol]] == category,]
>> dataSet <- extract(img, categorymap)
>> dataSet <- dataSet[!unlist(lapply(dataSet, is.null))]
>> if(is(sample, "SpatialPointsDataFrame")){
>> dataSet <- cbind(dataSet, class = as.numeric(category))
>> pixeles <- rbind(pixeles, dataSet)
>> }
>> if(is(sample, "SpatialPolygonsDataFrame")){
>> dataSet <- lapply(dataSet, function(x){cbind(x, class =
>> as.numeric(rep(category,
>>
>> nrow(x})
>> df <- do.call("rbind", dataSet)
>> pixels <- rbind(pixeles, df)
>> }
>>
>> }
>>
>> THIS IS THE ERROR I GET FROM RUNNING THE ABOVE CODES
>>
>>> for (i in 1:length(unique(samples[[responseCol]]))){
>> + category <- unique(samples[[responseCol]])[i]
>> + categorymap <- samples[samples[[responseCol]] == category,]
>> + dataSet <- extract(img, categorymap)
>> +
>> + if(is(sample, "SpatialPointsDataFrame")){
>> + dataSet <- cbind(dataSet, class = as.numeric(category))
>> + pixeles <- rbind(pixeles, dataSet)
>> + }
>> + if(is(sample, "SpatialPolygonsDataFrame")){
>> + dataSet <- lapply(dataSet, function(x){cbind(x, class =
>> as.numeric(rep(category,
>> +
>> nrow(x})
>> + df <- do.call("rbind", dataSet)
>> + pixels <- rbind(pixeles, df)
>> + }
>> +
>> + }
>> Error in y[i, ] :
>> cannot get a slot ("Polygons") from an object of type "NULL"
>>
>>
>> Please help me out.
>> Thank you.
>>
>> Best regards,
>>
>> Enoch
>>
>> --
>> *Enoch Gyamfi - Ampadu*
>>
>> *Geography & Environmental Sciences*
>>
>> *College of Agriculture
Re: [R-sig-Geo] regression-kriging and co-kriging (Edzer Pebesma)
Dear Edzer,
sorry for bothering you once more but I need to be sure about my R
script.
In summary, i'm comparing the performance of regression-kriging and
collocated co-kriging.
Regression-kriging was based on an unique covariate, the elevation Z.
I use Z as unique ancillary variable in the Co-kriging.
As first attempt, the final raster maps were completely different. It
appeared that it was due
to the fact that the dataset was non-stationary and only
regression-kriging overcomes this issue, while co-kriging not.
But if I pass to universal co-kriging introducing Z as covariate, it
bacomes useless as ancillary variable!
What is my mistake?
emanuele
Il 2019-08-15 12:00 r-sig-geo-requ...@r-project.org ha scritto:
Send R-sig-Geo mailing list submissions to
r-sig-geo@r-project.org
To subscribe or unsubscribe via the World Wide Web, visit
https://stat.ethz.ch/mailman/listinfo/r-sig-geo
or, via email, send a message with subject or body 'help' to
r-sig-geo-requ...@r-project.org
You can reach the person managing the list at
r-sig-geo-ow...@r-project.org
When replying, please edit your Subject line so it is more specific
than "Re: Contents of R-sig-Geo digest..."
Today's Topics:
1. Error running codes (Enoch Gyamfi Ampadu)
2. Re: regression-kriging and co-kriging (Edzer Pebesma)
--
Message: 1
Date: Thu, 15 Aug 2019 06:51:49 +0200
From: Enoch Gyamfi Ampadu
To: r-sig-geo@r-project.org
Subject: [R-sig-Geo] Error running codes
Message-ID:
Content-Type: text/plain; charset="utf-8"
Dear List,
Please I have been running a certain the codes below to read my image,
shapeffile to enable me classify for cover with Random forest. I have
gotten to the point of extracting the raster values and the raster
information. However I keep getting errors. though I have tried
different
combination and other codes like readOGR for importing the training
polygon. I will be glad if you could be of help as I am new to using R.
#import clip image of study area
TestImg3 <- brick("C:\\Users\\hp\\Desktop\\Data collection\\Nkandla
Images\\Landsat\\2019\\08052019\\Corrected\\New
Folder\\Image08052019_Clip.tif")
#Assign name of bands
names(TestImg3) <- c(paste0("B", 1:7, coll=""), "B9")
plotRGB(TestImg3, r=4, g=3, b=2, stretch ="lin")
#Import training shapefile
sample <- shapefile("C:/Users/hp/Desktop/Data collection/Nkandla
Images/Landsat/2019/08052019/Corrected/Train08052019_2.shp")
responseCol <- "class"
#(I have tried options of changing "class" to "classname" as reflect
actaul
name assigned in ArcMap)
# Overlap the sample polygons on the image (combine the class
information
with extracted values).
pixels = data.frame(matrix(vector(), nrow = 0, ncol =
length(names(img)) +
1))
for (i in 1:length(unique(sample[[responseCol]]))){
category <- unique(sample[[responseCol]])[i]
categorymap <- sample[sample[[responseCol]] == category,]
dataSet <- extract(img, categorymap)
dataSet <- dataSet[!unlist(lapply(dataSet, is.null))]
if(is(sample, "SpatialPointsDataFrame")){
dataSet <- cbind(dataSet, class = as.numeric(category))
pixeles <- rbind(pixeles, dataSet)
}
if(is(sample, "SpatialPolygonsDataFrame")){
dataSet <- lapply(dataSet, function(x){cbind(x, class =
as.numeric(rep(category,
nrow(x})
df <- do.call("rbind", dataSet)
pixels <- rbind(pixeles, df)
}
}
THIS IS THE ERROR I GET FROM RUNNING THE ABOVE CODES
for (i in 1:length(unique(samples[[responseCol]]))){
+ category <- unique(samples[[responseCol]])[i]
+ categorymap <- samples[samples[[responseCol]] == category,]
+ dataSet <- extract(img, categorymap)
+
+ if(is(sample, "SpatialPointsDataFrame")){
+ dataSet <- cbind(dataSet, class = as.numeric(category))
+ pixeles <- rbind(pixeles, dataSet)
+ }
+ if(is(sample, "SpatialPolygonsDataFrame")){
+ dataSet <- lapply(dataSet, function(x){cbind(x, class =
as.numeric(rep(category,
+
nrow(x})
+ df <- do.call("rbind", dataSet)
+ pixels <- rbind(pixeles, df)
+ }
+
+ }
Error in y[i, ] :
cannot get a slot ("Polygons") from an object of type "NULL"
Please help me out.
Thank you.
Best regards,
Enoch
--
*Enoch Gyamfi - Ampadu*
*Geography & Environmental Sciences*
*College of Agriculture, Engineering & Science*
*University of KwaZulu-Natal, Westville Campus*
*Private Bag X54001*
*Durban, South Africa **– 4000**.*
*Phone: +27 835 828255*
*email: egamp...@gmail.com *
*skype: enoch.ampadu*
*The highest evidence of nobility is self-control*.
*A simple act of kindness creates an endless ripple*.
[[alternative HTML version deleted]]
--
Message: 2
Date: Thu, 15 Aug 2019 08:33:59 +0200
From: Edzer Pebesma
To: r-sig-geo@r-project.org
Subject: Re: [R-sig-Geo] regression-kriging and co-kriging
Message-ID:
Content-Type: text/plain; charset="utf-8"
On 8/12/19 8:21 PM, Emanu
