I am (very) new to GIS in general. I would like to convert a satellite image of a province into raster, assigning each pixel its own data (i.e., a number and a name) based on its html color code. For example, shades of red and/or blue would be assigned the data "id=1; name=Residential" and shades of light green would be "id=2; name=grassland" and green to dark green would be "id=3; name=forest".
I'm thinking of taking screen shots (zoomed in as much as possible) and then combining them to capture the whole province. Next, I'll georeference the image.
How could I go about this next?