[R-sig-Geo] Map digitization and classification

[Barry Rowlingson]

On Fri, Mar 18, 2011 at 9:44 PM, tsippel <tsippel at gmail.com> wrote:
> I have a series of scanned global maps (from a bound Atlas) of oceanographic
> sampling effort that I would like to classify. On 1 x1 lat/lon grids are
> symbols that represent sampling density.  I need to read in these scanned
> maps, and classify the symbols (squares are classified as 1, triangles as 2,
> etc.) and hopefully store them in raster grid files (.asc) for analysis.
>
> After some trawling through CRAN looking for packages for this, it is not
> yet apparent to me which is best.  I've considered using a GIS for this (ie.
> GRASS), but I'm not sure if that is a more complicated solution to a simpler
> problem.  I need to process a directory of these images, so scripting the
> process to loop over the directory would be ideal.

 So you've got some high resolution page images and want to do
recognition of the shapes in the grid cells?

 Depending on how much noise there is it might be easy or difficult...
Any chance you can get us a sample image, or a section of one? How
many different symbols are there, and how big is the grid? I guess
global means 360x180, but what's the image resolution? Is there also a
map outline background to confuse things? MIght be easier to attack
this with an image processing toolbox like imageJ...

Barry