Counts of 554 aphids of the species Sitobion avenae, sampled on 28 June 1996 in a 250 x 180-m field of winter wheat near Wimborne, Dorset, UK. The 63 sampling units, made of the inspection of five tillers each, were located on a 9 x 7 rectangular grid at intervals of 30 m.



A data frame with 63 rows and 3 variables:

[, 1:2]x,yGrid spatial coordinates.
[, 3:4]xm,ymMetric spatial coordonates.
[, 5]iCounts of aphids.


Perry JN, Winder L, Holland JM, Alston RD. 1999. Red-blue plots for detecting clusters in count data. Ecology Letters 2, 106-13. doi:10.1046/j.1461-0248.1999.22057.x