Interactive maps
On Sun, 26 Apr 2015 at 00:56 Antonio Serrano via R-help <
r-help at r-project.org> wrote:
Thank you, Jim. I didn't know the existence of the locator() function. But I can see now that I don't know how to read a graphic image into R to work with it. How can I read a pre-exisiting image into R?. See the raster (and possibly rgdal - depending on your format/s) package
to read in images that are georeferenced. Depending on the provenance of your files, it might be as simple as doing library(raster) r <- raster(filename) plort(r) xy <- locator(, type = "p") ## click on the map If the values of these are not right you'll need further digging, and perhaps if your image is not in longitude/latitude you'll need to transform the locator points. Also check out ?getGraphics event in grDevices, which can be used (with care) to build quite complex interactive applications. Another promising option is to use a Shiny application, where each plot gives a simple way to get click events from the user - but then you really are building an application out in the frontier edges of R land. Cheers, Mike. Thanks again
Antonio Serrano aasdelat at aim.com ? -----Original Message----- From: Jim Lemon <drjimlemon at gmail.com> To: Antonio Serrano <aasdelat at aim.com> Cc: r-help mailing list <r-help at r-project.org> Sent: Sat, Apr 25, 2015 5:47 am Subject: Re: [R] Interactive maps Hi Antonio, If you do create the map in R, you can use locator(). Jim On Sat, Apr 25, 2015 at 8:37 AM, Antonio Serrano via R-help <r-help at r-project.org> wrote:
Hello, all: I am new here,
and have a challenge to present some graphical data to the user in a convenient way.
The challenge is to present a map to the user which is coloured
with the value of a variable. Say for example, temperature. This is a preexisting graph that I can generate in any format, including svg. I don't have to produce it using R.
When the user clicks anywhere in the map, the
coordinates (longitude and latitude) have to be passed to R so that this, R, can look for the values of other variables in that location and make another graph with them.
Does anyubody know how could I accomplish this?.
Thanks in advance.
Antonio Serrano aasdelat at aim.com ?
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