similar to: Convert date to continuous variable in R

How can I convert date to continuous variable staring from 1. I tried as.numeric but R starts counting from default January 1, 1970 while my data start Oct 7, 2009. I need to do this conversion to plot the date on two x-axes (1 and 3). Ex; Date LAI 10/7/2009 0 10/8/2009 0.004173 10/9/2009 0.009997 10/10/2009 0.009998 10/11/2009 0.009999 10/12/2009 0.009999 10/13/2009 0.009999 10/14/2009 0.009999

The model should be class aov or lm and my model class is aovlist. tried tidy from broom library but did not work. To make it class aov, I had to remove the error term; model <- aov(Rotationdata_R$`GY(Mg/ha)`~Rep+code*as.factor(Nitrogen),data=Rotationdata_R) Ahmed Attia, Ph.D. Agronomist & Soil Scientist On Mon, Dec 25, 2017 at 7:38 PM, David Winsemius <dwinsemius at

> On Dec 25, 2017, at 2:09 PM, Ahmed Attia <ahmedatia80 at gmail.com> wrote: > > The model should be class aov or lm and my model class is aovlist. > tried tidy from broom library but did not work. To make it class aov, > I had to remove the error term; > > model <- aov(Rotationdata_R$`GY(Mg/ha)`~Rep+code*as.factor(Nitrogen),data=Rotationdata_R) You seemed to have

Sorry for the confusion, here is the edited question. The data= Stand_Height (attached) is recorded from 12/1/2009 to 12/31/2015 (25 observations) and the other dataset (leafbiom) is recorded from 10/7/2009 to 12/29/2016 (daily observations). I want to use the 25 observations of stand height to predict the daily stand height from 10/7/2009 to 12/29/2016. The daily stand height will be multiplied

Hi R users, I need your help to write a code in r that does the following calculation from three different datasets; ac = 1/sum (NPP from date 1 to date 2, dataset=1) * (biomass at date 2 -biomass at date 1, dataset = 2) + (littfall at date 2, dataset=3). all the dates are in yr-month-day format. Which library or function Should I use to tell R do these calculations of these variables at

Hi Ahmed, Your problem appears trivial as you have already specified the form of the calculation. Learn how to "extract" specified elements from a data structure: # first value sum(dataset1$NPP[dataset1$date >= date1 & dataset1$date <= date2]) # second value dataset2$biomass[dataset2$date == date2] - dataset2$biomass[dataset2$date == date1] # third value

There are a bunch of things wrong here, although without a reproducible example I can't really fix most of them. - You're overwriting SH within the loop. - You're running the regression 2641 times, even though the result never changes. - You're never predicting from your linear model using the other data not in the regression. - Leaf biomass data is never used for anything. I

Once again, you are over-writing your variable. This time, you are overwriting the entirety of Stand_Height with the timeseries of height. Perhaps you should spend some time with one of the good introductory R resources out there, and think a bit more about your procedure. Sarah On Fri, Jun 30, 2017 at 11:23 AM, Ahmed Attia <ahmedatia80 at gmail.com> wrote: > Sorry for the confusion,

LSD-test produces error for this code; code <- as.factor(Rotationdata_R$`Rot/code`) #factor in the main Nitrogen <- as.factor(Rotationdata_R$Nitrogen) #factor in the sub Rep <- as.factor(Rotationdata_R$REP) #blocks Year <- as.factor(Rotationdata_R$YEAR) #years model <- aov(Rotationdata_R$`GY(Mg/ha)`~Rep+code*as.factor(Nitrogen)+Error(Rep/Year/code),data=Rotationdata_R)

Hi folks, I have 25 stand height observations over 7 years period and daily leafbiomass data during this period. I want to use the 25 plant height observations as inputs and predict the daily stand height during the 7 years. SH=matrix(data=NA , nrow = 2641, ncol = 1) for (i in 1:2641) { SH<- predict(lm(height~Date, data=Stand_Height)); dl=leafbiom$Date[i-1]; de=leafbiom$Date[i];

Hi Ahmed, When reading from a ncdf file you can use the 'varname', 'lvar' and 'level' arguments - see the 'Details' section in the docs https://www.rdocumentation.org/packages/raster/versions/2.6-7/topics/raster <https://www.rdocumentation.org/packages/raster/versions/2.6-7/topics/raster> We can't tell what is in the ncdf file from what you report other

> On Dec 25, 2017, at 10:21 AM, Ahmed Attia <ahmedatia80 at gmail.com> wrote: > > LSD.test ?LSD.test No documentation for ?LSD.test? in specified packages and libraries: you could try ???LSD.test? -- David Winsemius Alameda, CA, USA 'Any technology distinguishable from magic is insufficiently advanced.' -Gehm's Corollary to Clarke's Third Law

---------- Forwarded message ---------- From: <r-help-owner@r-project.org> Date: Mon, Jan 14, 2013 at 12:31 AM Subject: Help with nonlinear regression To: ahmedatia80@gmail.com The message's content type was not explicitly allowed ---------- Forwarded message ---------- From: Ahmed Attia <ahmedatia80@gmail.com> To: r-help@r-project.org Cc: Date: Mon, 14 Jan 2013 00:31:41 -0800

Hi I have a netCDF file of volumetric soil water content at four different soil layers and want to convert each soil layer in the netCDF file to a GeoTIFF layer. This code converts the netCDF file to one GeoTIFF layer, i.e. unclear which soil depth. file.nc <- "C:/Soil_Weather_data/Agro/VMC21/VMC21.nc" file.tiff <- "C:/Soil_Weather_data/Agro /VMC21/VMC21" importnetcdf

Dear All, I'm a beginner user in R and I would like to make a quadratic and plateau model in R. Can you help please with an example? Thanks so much -- Ahmed M. Attia Assistant Lecturer El-Khattara farm Station Agronomy Dept., Zgazig Univ., Egypt Visiting Scientist Haskell Agricultural laboratory Agronomy and Horticultural Dept., Univ. of Nebraska-Lincoln ahmedatia at zu.edu.eg

Hello R users, The code below is for loop in R that I want to do to following calculation at each time i and i-1 in 2:75 dataset (Litterfall_Ahmed97). ac = ((LeafBiog at date i -LeafBiog at date i-1, dataset = leafbiom97) + (littperiod at date i, dataset= Litterfall_Ahmed97))/(sum (GPP from date i-1 to date i, dataset=GPP_Ahmed13)/2) . #code for loop GPP_Ahmed13$Date <-

I have probably an old question. I have R.3.0.1 installed in 64 bit windows 7. The odbcConnectExcel in RODBC library does not work. Tried odbcConnectExcel2007 still does not work. Any ideas. Thanks Melissa<-sqlFetch(odbcConnectExcel2007("F:\\Cotton2012\\validation.xlsx"),sqtable = "Sheet3", + na.strings = "NA", as.is = TRUE) Error in

Please help getting the R squared value in asymptotic regression model I use the code below model1<-nls(GN1~SSasymp (nrate,a,b,c), data = data.1 ) and R produced the modell coefficients without the R squared value? -- Ahmed M. Attia Research Assistant Dept. Of Soil&Crop Sciences Texas A&M University ahmed <ahmedatia@zu.edu.eg>.attia@ag.tamu.edu Cell phone:

I have 11 vectors representing insect survival probabilities in response to different levels of toxins at 10 concentrations lx100=c(1,1,1,.8,.5,.4,.2,0) day100=c(0,1,2,3,4,5,6,7,8) lx90=c(1,1,1,1,.9,.8,.6,.4,.2,.1,0) day90=c(0,1,2,3,4,5,6,7,8,9,10) #...and so on10% and a zero (control) series lx0=c(1,1,1,1,1,1,.9,.9,.8,.8,.6,.5,.4,.3,.2,.1,.1,0)

Dear R users, Can I fit nls.lm to a non-continuous date data. looked at previous examples but still not able to fit the model to my data. There are 25 rows of observations as below; df <- data.frame(Date=as.Date(rownames(df),'%m/%d/%Y'),Y=df$height) df$days <- as.numeric(df$Date - df[1,]$Date) head(df) Date Y days 1 2009-12-01 0.2631250 0 2 2010-01-08 0.4436012