I am having 15 polygon shape files of a sub locality of a city that is having address in their attribute table. I want to merge these polygons based on the address in the attribute table?how can i do this in Qgis. I also attempted vector...>>>data management tools...>>>>merge shape files to one.But it is giving me the combined polygon but when I look into the attribute table the values shows me null? What is the problem behind it?
dissolve tool did not work for me, so I'm solving this on rails :)
Now this solution might not be good for some, because you have to load in every parcel into a database, but I had already done that so it worked for me.
Here's my pseudo code, I haven't run anything yet
Polygon.all.each do |p| if check_if_superpolygon_exists(p) if check_if_contiguous_superpolygon_exists(p) add_to_contiguous_superpolygon(p) else create_new_superpolygon(p) end else create_new_superpolygon(p) end end
check_if_contiguous_superpolygon_exists will use ST_Intersects & the others will just check if records exist with the same attribute-value and stuff. The only tricky part I haven't done yet is merging a new polygon into the superpolygon's spatial data.