Point pattern of retinal ganglion cells identified as ‘on’ or ‘off’. A marked point pattern.
An object of class
representing the point pattern of cell locations.
||Cartesian x-coordinate of cell|
||Cartesian y-coordinate of cell|
|| factor with levels
|indicating ``off'' and ``on'' cells|
ppp.object for details of the format.
Important: these data are INCORRECT. See below.
The data represent a pattern of beta-type ganglion cells in the retina of a cat recorded in Figure 6(a) of W\"assle et al. (1981).
The pattern was first analysed by W\"assle et al (1981) using nearest neighbour distances. The data used in their analysis are not available.
The present dataset
scanned from Figure 6(a) of W\"assle et al (1981)
in the early 1990's, but we have no further information.
This dataset is the one analysed by Van Lieshout and Baddeley (1999)
using multitype J functions, and by Stoyan (1995) using second
order methods (pair correlation and mark correlation).
It has now been discovered that these data are incorrect. They are not faithful to the scale in Figure 6 of W\"assle et al (1981), and they contain some scanning errors. Hence they should not be used to address the original scientific question. They have been retained only for comparison with other analyses in the statistical literature.
A new, corrected dataset, scanned from the original microscope image,
has been provided under the name
betacells. Use that
dataset for any further study.
These data are incorrect.
Use the new corrected dataset
W\"assle et al (1981), data supplied by Marie-Colette van Lieshout and attributed to Peter Diggle
Stoyan, D. (1995) Personal communication.
Van Lieshout, M.N.M. and Baddeley, A.J. (1999) Indices of dependence between types in multivariate point patterns. Scandinavian Journal of Statistics 26, 511–532.
W\"assle, H., Boycott, B. B. & Illing, R.-B. (1981). Morphology and mosaic of on- and off-beta cells in the cat retina and some functional considerations. Proc. Roy. Soc. London Ser. B 212, 177–195.
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