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Computes the spatial correlation coefficient (Moran's I) of a vector given a distance matrix, and a distance threshold used to define "neighborhood".

Usage

moran(
  x = NULL,
  distance.matrix = NULL,
  distance.threshold = NULL,
  verbose = TRUE
)

Arguments

x

Numeric vector, generally model residuals, Default: NULL

distance.matrix

Distance matrix among cases in x. The number of rows of this matrix must be equal to the length of x. Default: NULL

distance.threshold

numeric value in the range of values available in distance.matrix. Distances below such threshold are set to 0. Default: NULL (which defaults to 0).

verbose

Logical, if TRUE, prints a Moran's I plot. Default: TRUE

Value

A list with three named slots:

  • test: Data frame with observed and expected Moran's I values, p-value, and interpretation.

  • plot: Moran's plot of the vector x against the spatial lags of x.

  • plot.df: Data used in the Moran's plot.

Details

Inspired in the Moran.I() function of the ape package.

Examples


 #loading example data
 data(distance_matrix)
 data(plant_richness_df)

 #Moran's I of the response variable
 out <- moran(
   x = plant_richness_df$richness_species_vascular,
   distance.matrix = distance_matrix
   )

 out
#> $test
#>   distance.threshold moran.i.null   moran.i p.value
#> 1                  0 -0.004424779 0.4019806       0
#>                 interpretation
#> 1 Positive spatial correlation
#> 
#> $plot

#> 
#> $plot.df
#>         x      x.lag
#> 1    4835  4368.3183
#> 2    4360  5909.4259
#> 3    1362  1604.9887
#> 4    7818  4863.0757
#> 5   10394  8523.0261
#> 6    2690  7123.0241
#> 7    5109  6395.6429
#> 8    7372  4017.7514
#> 9    2766  3077.2355
#> 10   4254  5578.2924
#> 11   2610  3178.1693
#> 12   2502  3883.8773
#> 13    492   498.8487
#> 14   6084  6684.7941
#> 15  10248  6429.4275
#> 16   7963  6353.2393
#> 17   3976  5073.5762
#> 18   4253  4158.5834
#> 19   4110  3894.2505
#> 20   2578  6414.4450
#> 21   7546  8385.7792
#> 22   6940  6923.7338
#> 23  15207  4283.8823
#> 24   2502  3108.6868
#> 25    566   962.0570
#> 26   7158  7035.2828
#> 27   2169  2310.5125
#> 28   2507  5953.2691
#> 29    904  1359.3426
#> 30   1162   804.6076
#> 31   2435  3278.0874
#> 32   8874  6647.0586
#> 33   4939  7626.1568
#> 34   3398  2867.0901
#> 35   5893  6293.7076
#> 36   5861  7823.0254
#> 37   1986  3638.6749
#> 38   2503  4620.5206
#> 39    760   879.8758
#> 40   1056  1839.7473
#> 41   2324  2311.4758
#> 42   4119  2564.0549
#> 43   2362  3011.7135
#> 44   3017  3212.9472
#> 45   2774  4393.8251
#> 46   2656  2875.5411
#> 47   2014  2780.6413
#> 48   1353  5283.7504
#> 49   1461  2330.0667
#> 50   4767  4187.5883
#> 51   4426  4908.8691
#> 52   2776  3052.9065
#> 53   1489  2167.3774
#> 54   2942  2614.5905
#> 55    397   799.4982
#> 56  11751  7681.5538
#> 57   3831  2345.3673
#> 58   1279  3071.4096
#> 59    681  3986.2620
#> 60    777   904.0946
#> 61   1981  2535.9755
#> 62   1466  6681.7905
#> 63  10813  6731.3003
#> 64   6103  3816.9916
#> 65   2887  4166.2646
#> 66   3231  7489.2782
#> 67  11213  9088.8757
#> 68   5175  7185.4311
#> 69   1016  1093.9574
#> 70   3784  3364.9129
#> 71   4866  7477.1001
#> 72   1162  1120.7208
#> 73  11637  7101.9210
#> 74   5374  3666.8794
#> 75   4886  4257.8382
#> 76    288  1206.2662
#> 77   2279  6884.7060
#> 78   1740  5127.3180
#> 79    370  3837.5450
#> 80   3306  3317.0790
#> 81   2176  4798.6409
#> 82   1335  1524.1047
#> 83   2143  6789.9206
#> 84   2225  2788.8132
#> 85   3586  4337.8403
#> 86    683   800.5768
#> 87   2324  3855.0199
#> 88   2127  6271.5716
#> 89   2758  4118.1962
#> 90   1626  1893.8264
#> 91   5456  3662.1279
#> 92    807  3880.5085
#> 93   1495  3753.7027
#> 94  10237  7241.7882
#> 95   3873  8880.8585
#> 96   4247  4985.6259
#> 97   9762  6663.5340
#> 98   7481  8003.7927
#> 99  10738  8836.8818
#> 100  2960  5557.4603
#> 101  2814  2830.9187
#> 102  5324  5787.1852
#> 103  1746  1958.6108
#> 104  1463  4090.6375
#> 105  3859  3668.4180
#> 106  1877  2767.6785
#> 107  7100  6584.0362
#> 108  3555  4659.7921
#> 109  6773  9529.4151
#> 110   583  5002.8990
#> 111  1946  6409.7379
#> 112  3996  2711.0997
#> 113  2130  3568.4787
#> 114   390  5132.6664
#> 115  7158  9397.8923
#> 116   663   838.8103
#> 117  1900  3523.5747
#> 118  1233  4363.7955
#> 119  2977  4063.6008
#> 120   922  1009.9923
#> 121   768  2178.5612
#> 122 11893  4663.6103
#> 123  1337  1083.1607
#> 124  3552  3859.0821
#> 125  3156  4050.0754
#> 126  4174  7033.6847
#> 127  2699  7780.5820
#> 128  3799  3549.1571
#> 129  2513  4790.2413
#> 130  3293  2651.8489
#> 131  4129  5439.9601
#> 132  2156  2220.0287
#> 133   874  1048.7245
#> 134  4349  1916.2288
#> 135  7677  6915.3229
#> 136 10302  6134.9954
#> 137   979   970.9996
#> 138  2121  2864.7848
#> 139  2731  4793.2146
#> 140  1058  1192.4013
#> 141  7669  3805.1163
#> 142  2704  3377.3832
#> 143  1240  1213.6701
#> 144  5745  6842.0618
#> 145  5352  6454.5336
#> 146   792  3287.1665
#> 147  2954  3084.7135
#> 148  3150  4302.4927
#> 149  1406  1556.8688
#> 150   316   452.0215
#> 151  2448  6611.0317
#> 152  2331  2741.3252
#> 153  6006  6381.5374
#> 154  2393  2735.2333
#> 155  6705  6512.2170
#> 156  8004  6464.5759
#> 157  7488  4925.3907
#> 158  2331  3028.2236
#> 159  2432  7027.6256
#> 160  9986  7099.4369
#> 161  2740  2541.7869
#> 162  2498  9498.4190
#> 163  5188  6996.1839
#> 164  6774  5153.5209
#> 165 22187  7395.7515
#> 166  2778  3785.9743
#> 167  5535  3538.1065
#> 168  1871  4818.6468
#> 169  1453  3268.6825
#> 170  1724  3860.0428
#> 171  7056  9885.6102
#> 172   703   924.7212
#> 173  1080   946.2533
#> 174  3468  7445.3538
#> 175  2408  3570.3173
#> 176  4414  3564.9578
#> 177  3364  5360.7608
#> 178 16958  8023.4315
#> 179  3111  5082.7382
#> 180   233   482.0102
#> 181  3963  4068.4379
#> 182  4978  6800.2922
#> 183   648   955.7915
#> 184  3894  3475.5145
#> 185  7345  6602.9181
#> 186  2824  4075.1437
#> 187  5100  8360.3885
#> 188  8513  5723.9092
#> 189  2631  2102.9004
#> 190  4011  3295.7322
#> 191  5364 11122.9172
#> 192 10709  6097.8733
#> 193  3433  2326.0115
#> 194  5432  6733.6451
#> 195  9960  6120.2914
#> 196   742   868.1924
#> 197   251  1138.3890
#> 198 19091  6161.2758
#> 199  1714  2500.1911
#> 200  1247  1239.2068
#> 201  2793  5242.1340
#> 202  2174  2250.7517
#> 203  6262  3966.3815
#> 204  6324  4810.3493
#> 205  3297  6750.9859
#> 206  4101  5326.6182
#> 207  7823  9076.8551
#> 208  1965  5791.1754
#> 209  2877  8868.0648
#> 210  1165  5694.9271
#> 211  2467  5319.3496
#> 212  3558  2828.2183
#> 213  5715  5242.4030
#> 214 12026  6689.6591
#> 215  4495  5275.1110
#> 216  9000  7961.2469
#> 217   847  1104.2053
#> 218  4489  6038.4730
#> 219   420  2353.6291
#> 220  2397  2738.6542
#> 221  2457  2652.6558
#> 222  1776  3568.3498
#> 223  5625  6952.2592
#> 224  4863  7009.4450
#> 225  3326  2152.1098
#> 226  3480  8542.7381
#> 227  1425  6664.6001
#> 
#> attr(,"class")
#> [1] "moran"