Coding and addition of explanatory variables

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Coding and addition of explanatory variables

Enoch Gyamfi Ampadu
Dear List,

Please I am doing a biomass analysis with a satellite image. The
explanatory variables include the satellite bands and vegetation indices. I
am using Random forest regression. I have added bands of the satellite
image to the model and it worked. However, when I tried to add the
vegetation indices (bands) I get error messages. I have put the codes I am
using below;

Model <- randomForest(class~ B1 + B2 + B3 + B4 + B5 + B6 + B7 + B8 + B9 +
B10 + B11 + B12 + DVI1, data = Trainingset, proximity=TRUE,
                            importance=TRUE).
The "DVI1" is the vegetation index variable band I tried to add to the
model.

Below is the error message I received.

"Error in eval(predvars, data, env) : object 'DVI1' not found"

   I will be glad if I could get some assistance on how to resolve it.

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: [hidden email] <[hidden email]>*


*skype: enoch.ampadu*
*The highest evidence of nobility is self-control*.

*A simple act of kindness creates an endless ripple*.

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Re: Coding and addition of explanatory variables

Julian M. Burgos
Very hard to say without a reproducible example.  But perhaps "DVI1" is not in your "Trainingset" dataframe?


________________________________
From: R-sig-Geo <[hidden email]> on behalf of Enoch Gyamfi Ampadu <[hidden email]>
Sent: Tuesday, June 9, 2020 14:06
To: Help R-Sig_Geo <[hidden email]>
Subject: [R-sig-Geo] Coding and addition of explanatory variables

Dear List,

Please I am doing a biomass analysis with a satellite image. The
explanatory variables include the satellite bands and vegetation indices. I
am using Random forest regression. I have added bands of the satellite
image to the model and it worked. However, when I tried to add the
vegetation indices (bands) I get error messages. I have put the codes I am
using below;

Model <- randomForest(class~ B1 + B2 + B3 + B4 + B5 + B6 + B7 + B8 + B9 +
B10 + B11 + B12 + DVI1, data = Trainingset, proximity=TRUE,
                            importance=TRUE).
The "DVI1" is the vegetation index variable band I tried to add to the
model.

Below is the error message I received.

"Error in eval(predvars, data, env) : object 'DVI1' not found"

   I will be glad if I could get some assistance on how to resolve it.

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: [hidden email] <[hidden email]>*


*skype: enoch.ampadu*
*The highest evidence of nobility is self-control*.

*A simple act of kindness creates an endless ripple*.

        [[alternative HTML version deleted]]

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Re: Coding and addition of explanatory variables

Roger Bivand
Administrator
On Tue, 9 Jun 2020, Julian Burgos wrote:

> Very hard to say without a reproducible example.  But perhaps "DVI1" is
> not in your "Trainingset" dataframe?

Thanks, here is a code example:

library(randomForest)
data(airquality)
set.seed(131)
ozone.rf1 <- randomForest(Ozone ~ Solar.R + Wind + Temp + Month + Day,
data=airquality, proximity=TRUE, importance=TRUE, na.action=na.omit)
print(ozone.rf1)
set.seed(131)
ozone.rf2 <- randomForest(Ozone ~ Solar.R + Wind + Temp + Month + day,
data=airquality, proximity=TRUE, importance=TRUE, na.action=na.omit)
# Error in eval(predvars, data, env) : object 'day' not found

Concise code examples always help to tease out problems,

Roger


>
>
> ________________________________
> From: R-sig-Geo <[hidden email]> on behalf of Enoch Gyamfi Ampadu <[hidden email]>
> Sent: Tuesday, June 9, 2020 14:06
> To: Help R-Sig_Geo <[hidden email]>
> Subject: [R-sig-Geo] Coding and addition of explanatory variables
>
> Dear List,
>
> Please I am doing a biomass analysis with a satellite image. The
> explanatory variables include the satellite bands and vegetation indices. I
> am using Random forest regression. I have added bands of the satellite
> image to the model and it worked. However, when I tried to add the
> vegetation indices (bands) I get error messages. I have put the codes I am
> using below;
>
> Model <- randomForest(class~ B1 + B2 + B3 + B4 + B5 + B6 + B7 + B8 + B9 +
> B10 + B11 + B12 + DVI1, data = Trainingset, proximity=TRUE,
>                            importance=TRUE).
> The "DVI1" is the vegetation index variable band I tried to add to the
> model.
>
> Below is the error message I received.
>
> "Error in eval(predvars, data, env) : object 'DVI1' not found"
>
>   I will be glad if I could get some assistance on how to resolve it.
>
> 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: [hidden email] <[hidden email]>*
>
>
> *skype: enoch.ampadu*
> *The highest evidence of nobility is self-control*.
>
> *A simple act of kindness creates an endless ripple*.
>
>        [[alternative HTML version deleted]]
>
> _______________________________________________
> R-sig-Geo mailing list
> [hidden email]
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fstat.ethz.ch%2Fmailman%2Flistinfo%2Fr-sig-geo&amp;data=02%7C01%7C%7C040a519515414dcf4ff508d80c7e6133%7C8e105b94435e4303a61063620dbe162b%7C0%7C0%7C637273084221502390&amp;sdata=yL%2BLWXZWZ0EaUNEXxLXpWnkkOgKeMriuuuJR47MUIhI%3D&amp;reserved=0
>
> [[alternative HTML version deleted]]
>
>
--
Roger Bivand
Department of Economics, Norwegian School of Economics,
Helleveien 30, N-5045 Bergen, Norway.
voice: +47 55 95 93 55; e-mail: [hidden email]
https://orcid.org/0000-0003-2392-6140
https://scholar.google.no/citations?user=AWeghB0AAAAJ&hl=en
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Roger Bivand
Department of Economics
Norwegian School of Economics
Helleveien 30
N-5045 Bergen, Norway