Placing Custom Images in a Plot Window--as custom data markers or to annotate those markers

Question

I have a set of 150x150px png images, and a set of (x, y) coordinates that they correspond to. Is there a way to plot the images on a grid? For example, I'm looking for an R or Python solution to create something like the following: enter image description here

Related: http://stackoverflow.com/questions/11487797/python-matplotlib-basemap-overlay-small-image-on-map-plot — 0 _, Jun 06 '15 at 21:32

doug · Accepted Answer · 2012-04-10T02:52:34.587

You create a bounding box by instantiating AnnotationBbox--once for each image that you wish to display; the image and its coordinates are passed to the constructor.

The code is obviously repetitive for the two images, so once that block is put in a function, it's not as long as it seems here.

import matplotlib.pyplot as PLT
from matplotlib.offsetbox import AnnotationBbox, OffsetImage
from matplotlib._png import read_png

fig = PLT.gcf()
fig.clf()
ax = PLT.subplot(111)

# add a first image
arr_hand = read_png('/path/to/this/image.png')
imagebox = OffsetImage(arr_hand, zoom=.1)
xy = [0.25, 0.45]               # coordinates to position this image

ab = AnnotationBbox(imagebox, xy,
    xybox=(30., -30.),
    xycoords='data',
    boxcoords="offset points")                                  
ax.add_artist(ab)

# add second image
arr_vic = read_png('/path/to/this/image2.png')
imagebox = OffsetImage(arr_vic, zoom=.1)
xy = [.6, .3]                  # coordinates to position 2nd image

ab = AnnotationBbox(imagebox, xy,
    xybox=(30, -30),
    xycoords='data',
    boxcoords="offset points")
ax.add_artist(ab)

# rest is just standard matplotlib boilerplate
ax.grid(True)
PLT.draw()
PLT.show()

enter image description here

This is great, do you know how to remove the border? – John M Jan 12 '15 at 21:36 — John M, Jan 12 '15 at 21:36
@JohnM Pass `frameon=False` to `AnnotationBbox()` – bdforbes Feb 17 '15 at 00:24 — bdforbes, Feb 17 '15 at 00:24

Paolo · Answer 2 · 2011-02-02T12:37:29.953

One way to do it in R (2.11.0 and higher):

library("png")
# read a sample file (R logo)
img <- readPNG(system.file("img", "Rlogo.png", package="png"))
# img2 <- readPNG(system.file("img", "Rlogo.png", package="png"))
img2 <- readPNG("hand.png", TRUE) # here import a different image 
if (exists("rasterImage")) { 
  plot(1:1000, type='n')
  rasterImage(img, 100, 100, 200, 200)
  rasterImage(img2, 300, 300, 400, 400)
}

see ?readPNG and ?rasterImage for details. enter image description here

score 3 · Answer 3 · answered Feb 01 '11 at 09:18

3

I would use matplotlib for that. this demo shows something similar, I am sure it can be adapted to your particular problem

answered Feb 01 '11 at 09:18

rymurr

444
4
11

score 3 · Answer 4 · answered Feb 02 '11 at 19:51

3

Also in R you can use the my.symbols and ms.image functions in the TeachingDemos package.

answered Feb 02 '11 at 19:51

Greg Snow

48,497
6
83
110

score 1 · Answer 5 · edited Feb 02 '11 at 11:15

In R, readed in the help(rasterImage):

require(grDevices)
#set up the plot region:
op <- par(bg = "thistle") <h>
plot(c(100, 250), c(300, 450), type = "n", xlab="", ylab="")
image <- as.raster(matrix(0:1, ncol=5, nrow=3))
rasterImage(image, 100, 300, 150, 350, interpolate=FALSE)
rasterImage(image, 100, 400, 150, 450)
rasterImage(image, 200, 300, 200 + xinch(.5), 300 + yinch(.3), interpolate=FALSE)
rasterImage(image, 200, 400, 250, 450, angle=15, interpolate=FALSE)
par(op)

....is a nice example.

Placing Custom Images in a Plot Window--as custom data markers or to annotate those markers

5 Answers5

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