Transition Class

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Description

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Class Definition

setClass(
  Class = "Transition",
  slots = c(
    lookupcolor = "character",
    transitionData = "tbl_df",
    transitionStationarity = "tbl_df"
  )
)

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Slots

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Slot Details

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For Gain of Category n

1. Period (<fct>): The period [Y_t, Y_t+1]
2. From (<fct>): A category i
3. To (<fct>): The gaining category in the transition of interest (n)
4. Interval (<int>): Duration of the period [Y_t, Y_t+1]
5. T_i2n_km2 or T_i2n_pixel (<dbl>): Area with transition from category i to category n during time interval [Y_t, Y_t+1] where i ≠ n
6. Rtin (<dbl>): Annual intensity of transition from category i to category n during time interval [Y_t, Y_t+1] where i ≠ n
7. Wtn (<dbl>): Value of the uniform intensity of the transition to category n from all non-n categories at time Y_t during time interval [Y_t, Y_t+1]

1. From (<fct>): The losing category in the transition of interest to category n
2. loss (<int>): Number of times the category had losses to category n
3. N (<int>): Total number of transitions to be considered as stationary (T)
4. Stationarity (<chr>): targeted by or avoided by category n
5. Test (<chr>): Y for stationarity detected and N when not

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For Loss of Category m

1. Period (<fct>): The period [Y_t, Y_t+1]
2. To (<fct>): A category j
3. From (<fct>): The losing category in the transition of interest (m)
4. Interval (<dbl>): Duration of the period [Y_t, Y_t+1]
5. T_m2j_km2 or T_m2j_pixel (<dbl>): Area with transition from category m to category j during time interval [Y_t, Y_t+1] where j ≠ m
6. Qtmj (<dbl>): Annual intensity of transition from category m to category j during time interval [Y_t, Y_t+1] where j ≠ m
7. Vtm (<dbl>): Value of the uniform intensity of the transition from category m to all non-m categories at time Y_t+1 during time interval [Y_t, Y_t+1]

1. To (<fct>): The gaining category in the transition of interest from category m
2. gain (<int>): Number of times the category had gains from category m
3. N (<int>): Total number of transitions to be considered as stationary (T)
4. Stationarity (<chr>): targeted or avoided category m
5. Test (<chr>): Y for stationarity detected and N when not

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Details

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Transition Level Analysis

• For gains: “Which categories are contributing most intensively to the gain of category n?”
• For losses: “Which categories are category m transitioning to most intensively?”

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Gain Analysis

• Rtin (Transition Intensity): Annual intensity of transition from category i to category n
• Wtn (Uniform Transition Intensity): Hypothetical intensity if all non-n categories contributed uniformly to n’s gain

• If Rtin > Wtn: Category n is targeting category i (gaining intensively from i)
• If Rtin < Wtn: Category n is avoiding category i (gaining less intensively from i)

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Loss Analysis

• Qtmj (Transition Intensity): Annual intensity of transition from category m to category j
• Vtm (Uniform Transition Intensity): Hypothetical intensity if category m transitioned uniformly to all non-m categories

• If Qtmj > Vtm: Category m is targeting category j (transitioning intensively to j)
• If Qtmj < Vtm: Category m is avoiding category j (transitioning less intensively to j)

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Stationarity Testing

• Targeted by/Targeted: Intensities are consistently above the uniform rate
• Avoided by/Avoided: Intensities are consistently below the uniform rate
• Test = Y: The pattern is stationary (consistent across all intervals)
• Test = N: The pattern is not stationary (varies across intervals)

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Usage in Intensity Analysis

# Run intensity analysis
my_test <- intensityAnalysis(
  dataset = SL_2002_2014,
  category_n = "Ap",  # Target category for gain analysis
  category_m = "SG"   # Target category for loss analysis
)

# Access the Transition level results
gain_transitions <- my_test$transition_lvlGain_n  # Transitions TO category "Ap"
loss_transitions <- my_test$transition_lvlLoss_m  # Transitions FROM category "SG"

# View the gain transitions
gain_transitions
#> An object of class "Transition"
#> Slot "lookupcolor":
#>        Ap        FF        SA        SG        aa        SF      Agua        Iu 
#> "#FFE4B5" "#228B22" "#00FF00" "#CAFF70" "#EE6363" "#00CD00" "#436EEE" "#FFAEB9" 
#> ...
#> 
#> Slot "transitionData":
#> # A tibble: 40 × 7
#>    Period    From  To    Interval T_i2n_km2  Rtin   Wtn
#>    <fct>     <fct> <fct>    <int>     <dbl> <dbl> <dbl>
#>  1 2012-2014 SG    Ap           2    350.    4.82  3.92
#>  2 2012-2014 aa    Ap           2     85.2   5.98  3.92
#>  3 2012-2014 SA    Ap           2     45.3   2.15  3.92
#> ...

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Plotting

plot(my_test$transition_lvlGain_n,
     labels = c(leftlabel = bquote("Gain of Ap (" ~km^2~ ")"),
                rightlabel = "Intensity Gain of Ap (%)"),
     marginplot = c(.3, .3),
     labs = c("Categories", "Uniform intensity"),
     leg_curv = c(x = 1, y = .5))

• The area of transition from each category to the target category
• The intensity of each transition compared to the uniform intensity

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See Also

• Interval - S4 class for Interval level analysis
• Category - S4 class for Category level analysis
• intensityAnalysis() - Function that creates Transition objects
• plot() - Method for visualizing Transition objects