Hi,
I guess that the "Union by attribute" function in OpenJUMP might be close to
what you want (Tools - Analysis - One layer - Union by attribute value).
Download the nightly snapshot from http://openjump.org and unzip. Increase
Java memory setting in the launch file that is located in the \bin -directory.
The file is openjump.bat for Windows, openjump.sh for Linux. The value you will
need to increase is "-Xmx256M". Try something like "Xmx1400M". Lets hope it
is enough for your dataset. OpenJUMP keeps all the data in memory and it is
not sure that it can handle your data. I am remembering that with 32 bit
Windows it is not possible to increase memory above about 1500M even if the
computer has more but I have read about 64 bit Linux user who was super happy
with 6 gigabytes.
I had a try with Vmap0 World boundaries and union by REGION made me for example
Europe and Asia multipolygons. Operation has an option for removing the common
boundaries where it is possible, and another one for summing up the numeric
fields. I suppose this is very close to what you want.
-Jukka Rahkonen-
________________________________
Lähettäjä: [email protected]
[mailto:[email protected]] Puolesta Lehr, Steven
Lähetetty: 16. syyskuuta 2010 18:14
Vastaanottaja: [email protected]
Aihe: [mapserver-users] Dissolve Tool?
Does anyone have a reliable dissolve tool that they would share. I
have many cases where I need to dissolve parcels on a parcel_id (maybe up to
200,000 polygons in the whole file); I know I can bring it down into ESRI, but
it adds multiple steps to my process. I'd like to have a Perl/python script
that does:
dissolve.pl parcels parcel_id
The output being a shapefile named parcels_dissolve.*
Where the inputs: parcels is a shapefile and parcel_id an attribute in
the .dbf; The .shp, .dbf etc would be processed appropriately dissolving on
the attribute passed in, so it could be parcel_id to dissolve parcels with
similar parcel_id, or could be an attribute like zoning; the resulting output
file would contain only one record in the .dbf file for each unique attribute.
Additionally the only attribute left in the .dbf would be the attribute being
dissolved on (unless you have the ability to sum area or count # of
occurrences; but no other logic about which fields to bring forth; just the one
attribute).
Thanks for the help. I'd be willing to pay for this project to be
written if someone is interested - drop me an email off list.
Steven Lehr
Associate Professor
College of Engineering
Embry-Riddle Aeronautical University (LB263)
600 S. Clyde Morris Blvd.
Daytona Beach, FL 32114-3900
386-226-7740
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