Hi
I'm working with some historical data on determinations of longitude
used by Michael F van Langren
in 1644 to draw what is believed to be the first graph of statistical
data. The values are estimates
of the distance in longitude between Toledo and Rome.
G. Iansonius 17.736 1501 Jan Jansson Flanders
[1588-1664] sb:~ 1615
G. Mercator 19.872 1567 Gerardus Mercator Flanders
I. Schonerus 20.638 1536 Johann Schöner Germany
P. Lantsbergius 21.106 1530 Phillip van Lansberge Belgium
T. Brahe 21.447 1578 Tycho Brahe Denmark
I. Regiomontanus 25.617 1471 Johann Muller Germany
[1436-1476] sb: 1463
Orontius 26.000 1542 Oronce Finé France
[1494-1555]
C. Clavius 26.340 1567 Christoph Clavius Germany
C. Ptolomeus 27.787 150 Claudius Ptolemaeus Alexandria
A. Argelius 28.170 1610 Andrea Argoli Italy
sb: 1610
A. Maginus 29.787 1582 Giovanni Antonio Magini Italy
D. Origanus 30.128 1601 David Origanus Germany
I want to show these overlaid on a map, something like the following:
http://euclid.psych.yorku.ca/SCS/Gallery/images/Private/Langren/langren-google-overlay.jpg
using *either* a jpeg image,
http://euclid.psych.yorku.ca/SCS/Gallery/images/Private/Langren/google-toledo-rome3.jpg
or a comparable portion of the world map, something like
# approximate coordinates of the BBox of this map
bbox <- c( 38.186, -9.184,
43.692, 28.674 )
bbox <- matrix(bbox, 2, 2, byrow=TRUE)
map("world", xlim=bbox[,2], ylim=bbox[,1], fill=TRUE, col=colors())
map.axes()
I created the overlay by manually rescaling and calibrating his graph
with a portion of a Google map.
But I'd like to be able to do this more exactly in R, possibly using
other data.
I can read in the data as follows:
langren <-
read.csv("http://euclid.psych.yorku.ca/SCS/Gallery/Private/langrens.csv";,
header=TRUE)
# Lat/Long of Toledo & Rome, from Google map
toledo <- c(39.86, -4.03)
rome <- c(41.89, 12.5)
# locations of the estimates, converted to lat, long
locations <- cbind( rep(rome[1], 12), toledo[2] + langren$long)
rownames(locations) <- langren$name
locations <- rbind( toledo, locations)
colnames(locations) <- c("lat", "long")
The above steps give:
locations <-
structure(c(39.86, 41.89, 41.89, 41.89, 41.89, 41.89, 41.89,
41.89, 41.89, 41.89, 41.89, 41.89, 41.89, -4.03, 13.706, 15.842,
16.608, 17.076, 17.417, 21.587, 21.97, 22.31, 23.757, 24.14,
25.757, 26.098), .Dim = c(13L, 2L), .Dimnames = list(c("toledo",
"G. Iansonius", "G. Mercator", "I. Schonerus", "P. Lantsbergius",
"T. Brahe", "I. Regiomontanus", "Orontius", "C. Clavius", "C. Ptolomeus",
"A. Argelius", "A. Maginus", "D. Origanus"), c("lat", "long")))
I can also read the .jpg Google map image, at least from a local file:
# read the google image
library(rimage)
gimage <-
read.jpeg("C:/Documents/milestone/images/vanLangren/google-toledo-rome3.jpg")
#gimageloc <-
"http://euclid.psych.yorku.ca/SCS/Gallery/images/Private/Langren/google-toledo-rome3.jpg";
#dest <- paste(tempfile(),'.jpg', sep='')
#download.file(gimageloc, dest)
# why doesn't this work?
#gimage <- read.jpeg(dest)
plot(gimage)
# approx pixel coordinates of Toledo and Rome in the image, measured
from the *top left* corner as (0,0)
toledo.map <- c(130, 119)
rome.map <-(505, 59)
Here's where I'm stumped. How can I recreate a version of van Langren's
graph shown on top of
either the gimage or on top of the portion of the R world map?
thanks
-Michael
--
Michael Friendly Email: friendly AT yorku DOT ca
Professor, Psychology Dept.
York University Voice: 416 736-5115 x66249 Fax: 416 736-5814
4700 Keele Street http://www.math.yorku.ca/SCS/friendly.html
Toronto, ONT M3J 1P3 CANADA
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![http://euclid.psych.yorku.ca/SCS/Gallery/images/Private/Langren/google-toledo-rome3.jpg"](http://euclid.psych.yorku.ca/SCS/Gallery/images/Private/Langren/google-toledo-rome3.jpg"){kind=link}