Congratulations to Yesudas Tharayil for successful submission of his M.Tech in Geoinformatics thesis on Simulation of land use change in Thiruvananthapuram Corporation, Kerala, India, using SimlandeR.
Yesudas has kindly agreed to make his thesis available to the community to help other researchers working with SimlandeR. The thesis is available here.
Just back from Morelia, México, where I have just given a 3 day training course in cellular automata land use modelling in R at the Centre for Research in Environmental Geography (CIGA), of the National Autonomous University of Mexico (UNAM). We used the SIMLANDER framework to simulate urban change patterns and then moved on to look at ways to incorporate actor behaviour into land use models with APoLUS. Was fantastic to meet so many like-minded researchers grappling with problems like deforestation, habitat degradation and global change issues generally. Thanks very much to Jean Francois Mas of CIGA for organising, and to everyone who attended for making me feel so welcome in México.
Trying not to bore people out of their minds talking about cell neighbourhood rules…
Course structure
Day 1:
Introduction to the topic (CA for modelling land use change)
R Tutorial 1: Introduction to working with geospatial data in R, general R commands, reclassification, simple scripting
R Tutorial 2: Making life easier in R, colours and legends, developing accessibility and suitability maps, more scripting.
Day 2:
R Tutorial 3: A simple CA model of urban land use change (SIMLANDER). Neighbourhood, random, zoning, transition potential, and land use demand.
Multiple land uses, multiple decisions – Introduction to APoLUS
R Tutorial 4: Calibrating the APoLUS model and running simulations.
Day 3:
R Tutorial 5: APoLUS – simulating actor decisions and developing scenario narratives
Group work and discussion
Day 4:
Conference: “Integrating actor behaviour in cellular automata models of land use change”)
Made some small but important modifications to the allocation script (see the readme file in the new download package for details).
To download the latest version, go here
Made some modifications to the allocation script (see the readme file in the new download package for details).
Main modifications include:
If you downloaded before today (6th June 2016), please download again now, I’ve updated the zip file.
To get the full prototype and user manual, go to here
Made some modifications to the allocation script (see the readme file in the new download package for details). If you downloaded before today (23rd May 2016), please download again now, I’ve updated the zip file.
To get the full prototype and user manual, go to here
Finally, after a long wait, a prototype version of SIMLANDER that works with multiple land uses is now available (see screenshot below)
To distinguish it from the earlier version that works only for 3 land uses, and to emphasise the addition of the actor characteristics module, the model has been renamed APoLUS (Actor, Policy and Land Use Simulator).
To get the full prototype and user manual, go here
The model code was written by Richard Hewitt for the EU FP7 project COMPLEX, except for the land use allocator, which was written by Maarten van de Meulen, in his free time.
If you are having trouble with the model or if you have any (constructive) comments, please email them to:
apolus@observatorioculturayterritorio.org
SIMLANDER R script versions 1.0.3 and 1.04
In Version 1.03, the selection of highest values from the transition potential map has been rewritten. Instead of extracting values through a GetValues command and then sorting, which I found difficult to code properly, the data are converted to a matrix, output to a dataframe (primarily to facilitate checking but also to make it easy to write out an excel file if desired) and then passed back to matrix again (almost certainly could be done in fewer lines of code, but it does work). A new raster is then generated with the highest values as “1” (urban land). This is the replacement code:
#Select the highest 164 values from the TTP map
#r1demand <- 164 #this is the number of cells we want to allocate from r1
x <- as.matrix(TTP)
n <- urbdemand1 #the demand, calculated by a countdown procedure, above
x2 <- sort(-x, partial = n)
x2h <- -sort(x2[1:n])
ix <- which(x %in% x2h)
ro <- ix %% 1151
ro <- ifelse(ro == 0L, 1151, ro)
co <- 1 + ix %/% 1151
x3 <- x[ix]
d <- data.frame(row = ro, col = co, x = x3)
result <- d[rev(order(d$x)), ]
#———————–
#turn selected 164 values in the dataframe into a matrix and then to a raster
x.mat <- matrix(0, 1151, 749) #create a matrix with the right number of rows and columns and fill with 0 values
#x.mat[cbind(result$row,result$col)] <-result$x #works just fine.
x.mat[cbind(result$row,result$col)] <-1 #but actually we want values to be 1 (urban land), not the TP value.
#which(!is.na(x.mat), arr.ind =TRUE) #pick out the non-NA values. Useful for testing that this has actually worked.
r <- raster(x.mat)
e <- extent(c(150938,225838,4070192,4185292))
extent(r) <- e
As in previous versions, new land to be allocated is calculated by: (urban cells in final map-urban cells in initial map/number of years). The new land to be allocated at each time step is then added to the existing urban land from the previous step. If this is not what you want, look at version 1.0.4.
SIMLANDER R script version 1.0.4
In Version 1.04, which includes all the updates made in version 1.0.3, the principal change relates to the way the land is allocated at each time step.
Instead of adding the new land (calculated by urban cells in final map-urban cells in initial map/number of years) to be allocated at each time step (e.g as in version 1.03) now the model allocates all of the urban land cells in the map at each time step, according to the results of the transition potential calculation. The total urban land in each time step is calculated by taking the cell count for urban from the initial map and then increasing the cells allocated at each time step until the final desired demand is reached.
This means that each time step is effectively a blank sheet, and that urban land can, if necessary disappear between time steps. Though there may be few cases in which this is desirable, this is much closer to the way that original CA models (like the game of life) work.
