-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hello all,
I am attempting to automate an analysis that I developed with ArcInfo using R and the gdal and geos packages (or any other) if possible. Here is the basic process I have a shape file (lines) that defines the limits of all of the projects with each project having a unique identifier. I have another shape file (polys) that contains total population and low income population and represent Census block groups. This shape file has an area field which has the acreage of the total block group. Process Step 1. I then buffer these project lines to create a second shape file that represents the 'footprint' of the project. (Creates polys). Step 2. In ArcInfo, I perform an intersection of the two shape files (footprint and census blocks) and this creates a third shape file which has a unique polygon for every project/census block intersection. Step 3. I then perform an area calculation (acres) on this new poly shape file and use this calculated area divided by the original area of the associated census block group to apportion the two population datum to this new polygon. Step 4. Finally, I sum the two population datums for each of the projects from the attribute table of this final shape file. When I try to replicate the above procedure I run into a problem with Step 2 when I use what I think is the appropriate command: gIntersects(buffered_projects, census_blocks, byID=TRUE) This command is producing a matrix of each project/census block combination and only providing me a true/false indication. Is there any way to replicate the process from ArcInfo that I outlined above within R? Walter Anderson -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJVFWYWAAoJEHfnxjvhypCiMc8P/2Dsja+h4RKuR7ygHx+oI+4/ oEIxl/NtnHwPh6szyL6CBndSYI6hvdWWwBUm86IsJLmLSSFivB1Ru54nkFq+kfKL tWpxyOAXNZoa2xn1ADaG1ChFiY/hF937zlTTv8D3a5pYAnYtTeyg6UJ3AuHsfjqG PbFAg6T+QD3AlJvV73JGmEchgYoj7NlxiEmdcfB3X9cgLMMOCsfLgm4d5g5J/mhh LKZm3Xg9+eXEjPJazHYB9xc0+AF8Jp6SH9XnnZ/DMFN3DuyR3KuTJr6YnHUKvtUs o/Uog3zAGuVUDqNwF1H9+WNuz4Fm7XXiHl4xX0n9faE3niTe2b63bVn/Ueiyofb9 ky3wIpAr412/Ne3dtMtSDPkE3w2TsdIUKki2VP9duXB/4vEtHHXvQxNtfKdKmlYX cnyyK/1ZwULiwWhyxZKJNUd6N2GyLYJ8MmJ7AXnT7EboJjNkhNta1BhWBE9Kzx8p fUN1UwS8P96iFXztgg2jw3aYTPdPIp9rFYFJax5nKCl6n+YbjUw11GuO6F4lqNDv PoLllcKkmsGWFo04P0TbS+x1zhc0wmyMn2EV8FcIXJ/80pqT/dWwksbjTfrQGoWx Xo1m1vTR2LVVrdf0vSkWnxHA3xVQPv7YH5erVNBGWvuhgbLRx8j7MPUp7lFHOJvQ bq1VJbpnZFRvJyZfII2p =cZWI -----END PGP SIGNATURE----- ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
