From: Thompson, David (MNR) <David.John.Thompson_at_ontario.ca>

Date: Wed, 04 Jun 2008 15:03:51 -0400

Silviculture Data Analyst

Ontario Forest Research Institute

Ontario Ministry of Natural Resources

david.john.thompson_at_ontario.ca

http://ontario.ca/ofri

R-help_at_r-project.org mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. Received on Wed 04 Jun 2008 - 19:53:03 GMT

Date: Wed, 04 Jun 2008 15:03:51 -0400

Hello,

A few questions about the following examples:
1. Why do the two plotting versions not produce the same result?
2. Is the 'scale_x_continuous' (or *_y_* or *_*_discrete) geom the best
way to setup grids (as in visual guide-lines) in polar (or for that
matter, any) coordinate system?

3. Why do these commands appear to generate 3 plot pages each?
4. Perhaps more questions to follow ;-)

### the data

test <- structure(list(oplt = c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L
), rplt = 1:10, az = c(57L, 94L, 96L, 152L, 182L, 185L, 227L,
264L, 332L, 354L), dist = c(4.09, 2.8, 7.08, 7.09, 3.28, 7.85,
6.12, 1.97, 7.68, 7.9)), .Names = c("oplt", "rplt", "az", "dist"
), row.names = c(NA, 10L), class = "data.frame")

labs <- structure(list(oplt = c(0, 0, 0, 0, 0), rplt = structure(c(3L, 1L, 4L, 5L, 2L), .Label = c("E", "N", "o", "S", "W"), class = "factor"),

az = c(0, 90, 180, 270, 360), dist = c(0, 16, 16, 16, 16)), .Names =
c("oplt",

"rplt", "az", "dist"), row.names = c(NA, -5L), class = "data.frame")

### plot version 1, setup plot structure first, add 'data' points later

ggplot() + coord_polar() +

layer( data = labs, mapping = aes(x = az, y = dist, label = rplt), geom
= "text") +

scale_x_continuous(breaks=c(90, 180, 270, 360)) +
layer( data = test, mapping = aes(x = az, y = dist, label = rplt), geom
= "text")

### plot version 2, try the same all in one step

ggplot() + coord_polar() +

layer( data = test, mapping = aes(x = az, y = dist, label = rplt), geom
= "text") +

scale_x_continuous(breaks=c(90, 180, 270, 360), labels=c('90', '180',
'270', '360'))

### the scenario

I am generating graphics to show the physical layout of a forestry
research experiment.

There are 54 'cut blocks' (64x64m, 0.4ha) each containing 1 circular
'overstory plot' (16m radius, 0.08ha).

Each 'overstory plot' (oplt) contains 10 circular 'regeneration plots'
(rplt) (0.56m radius, 1m^2 or 1.13m radius, 4m^2), these are the label
data points plotted below, later to have the 1m^2 or 4m^2 rplt outline
added.

Later, each individual tree will be plotted across each oplt in the
views below and each rplt in expanded views.
All locations (rplt centers, tree positions) are recorded as azimuth and
distance from their respective plot centers, hence my inclination to use
polar coordinates.

Thanx, DaveT.

Silviculture Data Analyst

Ontario Forest Research Institute

Ontario Ministry of Natural Resources

david.john.thompson_at_ontario.ca

http://ontario.ca/ofri

R-help_at_r-project.org mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. Received on Wed 04 Jun 2008 - 19:53:03 GMT

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