Hello R Community,
I have imported a dataset which contain X Y coordinates and would like to
recreate a shape file after some data analysis. What i have done is to
import some taxlot data and join them based on some criteria. I want to
check to see how well the joining went by reviewing the results in GIS.
A couple things. I cant seem to import a shape file correctly using the
maptools package and the readShapeSpatial. I have tried
Building=file("data/input/BuildingShape/Building.shp")
Bldg<-readShapeSpatial(fn=data/input/BuildingShape/Building,proj4string=NAD83)
#----------------------
Bldg<-readShapeSpatial(data/input/BuildingShape/Building,proj4string=NAD83)
#---------------
Building=file("data/input/BuildingShape/Building.shp")
Bldg<-readShapeSpatial(Building,proj4string=NAD83)
I know i am mis interpreting the documentation but it doesnt seem like it is
very complicated so i am of course confused.
Also, i am wondering if i can create a shape file by simply using XY
coordinates from a data frame.
So for:
Ycoord=c( 865296.4, 865151.5, 865457.0 ,865363.4 ,865311.0, 865260.9
,865210.7 ,865173.3,
865123.6 ,865038.2 ,864841.1 ,864745.4 ,864429.1 ,864795.6 ,864334.9
,864882.0)
Xcoord=c( 4227640 ,4227816 ,4228929 ,4228508 ,4229569 ,4229498 ,4226747,
4226781, 4229597,
4229204, 4228910, 4228959 ,4229465 ,4229794 ,4229596 ,4229082)
Lot<-c(1900 , 2000, 2100 , 100 ,200 , 300, 400 , 500 , 600 , 701 ,
900 , 1000 , 1100,
300 ,100, 200)
XYcoord<-spCbind(Ycoord,Xcoord) #doesnt work so
XYcoord=c(Ycoord,Xcoord)
TaxLots<-cbind(Ycoord,Xcoord,Lot)
writeSpatialShape(XYcoord, TaxLots..,
file=data/input/test/Taxlots,strictFilename=FALSE)
So help reading in shape files and then creating them using XY coordinates
if possible
Any help would be appreciated. Thank you.
--
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PDXRugger wrote:> > Hello R Community, > I have imported a dataset which contain X Y coordinates and would like > to recreate a shape file after some data analysis. What i have done is to > import some taxlot data and join them based on some criteria. I want to > check to see how well the joining went by reviewing the results in GIS. > > A couple things. I cant seem to import a shape file correctly using the > maptools package and the readShapeSpatial. I have tried > > Building=file("data/input/BuildingShape/Building.shp") > Bldg<-readShapeSpatial(fn=data/input/BuildingShape/Building,proj4string=NAD83) > #---------------------- > Bldg<-readShapeSpatial(data/input/BuildingShape/Building,proj4string=NAD83) > #--------------- > Building=file("data/input/BuildingShape/Building.shp") > Bldg<-readShapeSpatial(Building,proj4string=NAD83) > > I know i am mis interpreting the documentation but it doesnt seem like it > is very complicated so i am of course confused. > >I haven't used the maptools package for this kind of operation, so I offer any specific advice. However, the value of proj4string seems to be a little odd-- unless NAD83 is a variable that contains a string. It should probably be a quoted list of PROJ4 declarations such as: proj4string = '+proj=longlat +datum=NAD83' If maptools is leveraging the sp package, then you probably need to enclose the string in the CRS() function: proj4string = CRS('+proj=longlat +datum=NAD83') Note that the above example assumes coordinates are in lat/lon using the NAD83 datum. If your data is in a different projection, such as UTM, you will need to change the PROJ4 string accordingly. PDXRugger wrote:> > > Also, i am wondering if i can create a shape file by simply using XY > coordinates from a data frame. > So for: > > > Ycoord=c( 865296.4, 865151.5, 865457.0 ,865363.4 ,865311.0, 865260.9 > ,865210.7 ,865173.3, > 865123.6 ,865038.2 ,864841.1 ,864745.4 ,864429.1 ,864795.6 ,864334.9 > ,864882.0) > > Xcoord=c( 4227640 ,4227816 ,4228929 ,4228508 ,4229569 ,4229498 ,4226747, > 4226781, 4229597, > 4229204, 4228910, 4228959 ,4229465 ,4229794 ,4229596 ,4229082) > > Lot<-c(1900 , 2000, 2100 , 100 ,200 , 300, 400 , 500 , 600 , 701 > , 900 , 1000 , 1100, > 300 ,100, 200) > > XYcoord<-spCbind(Ycoord,Xcoord) #doesnt work so > > XYcoord=c(Ycoord,Xcoord) > > TaxLots<-cbind(Ycoord,Xcoord,Lot) > > writeSpatialShape(XYcoord, TaxLots.., > file=data/input/test/Taxlots,strictFilename=FALSE) > > > > So help reading in shape files and then creating them using XY coordinates > if possible > Any help would be appreciated. Thank you. > > >Maybe maptools provides a nice way to do this-- again I haven't used it much. My shapefile workflow usually centers on the sp and rgdal packages. First, sp is used to create a spatial object that holds the coordinates and data. Assuming you have point data: require(rgdal) lots <- SpatialPointsDataFrame( coords = cbind(Xcoord,Ycoord), data data.frame( Lot = Lot )) *Note that SpatialPointsDataFrame also takes a proj4string argument of the form: proj4string = CRS( 'proj declarations' ) I have omitted it since I don't know what projection your data is in. You can then create a shapefile using the writeOGR() routine in rgdal: writeOGR( lots, dsn = 'tstShapefile', layer = 'tstShapefile', driver='ESRI Shapefile') The readOGR() function can also be used to read a shapefile-- note that you give it the name of the directory containing the shapefile components and not the name of an individual component such as 'shapefile.shp'. Hope this helps! -Charlie ----- Charlie Sharpsteen Undergraduate Environmental Resources Engineering Humboldt State University -- View this message in context: http://www.nabble.com/Reading-and-Creating-Shape-Files-tp26098828p26114143.html Sent from the R help mailing list archive at Nabble.com.
Have you tried readShapePoints writePointsShape both in maptools. Also, I don't think you really need a proj4string specified unless you are actually doing some spatial operations such as buffers and distances. I take it that you have already considered and discarded the possibility of using using a unique ID for the tax records and after the analysis in R just joining the resulting table in a GIS to your original shapefile. Nikhil On 28 Oct 2009, at 1:33PM, PDXRugger wrote:> > Hello R Community, > I have imported a dataset which contain X Y coordinates and would > like to > recreate a shape file after some data analysis. What i have done is > to > import some taxlot data and join them based on some criteria. I > want to > check to see how well the joining went by reviewing the results in > GIS. > > A couple things. I cant seem to import a shape file correctly using > the > maptools package and the readShapeSpatial. I have tried > > Building=file("data/input/BuildingShape/Building.shp") > Bldg<-readShapeSpatial(fn=data/input/BuildingShape/ > Building,proj4string=NAD83) > #---------------------- > Bldg<-readShapeSpatial(data/input/BuildingShape/ > Building,proj4string=NAD83) > #--------------- > Building=file("data/input/BuildingShape/Building.shp") > Bldg<-readShapeSpatial(Building,proj4string=NAD83) > > I know i am mis interpreting the documentation but it doesnt seem > like it is > very complicated so i am of course confused. > > > Also, i am wondering if i can create a shape file by simply using XY > coordinates from a data frame. > So for: > > > Ycoord=c( 865296.4, 865151.5, 865457.0 ,865363.4 ,865311.0, 865260.9 > ,865210.7 ,865173.3, > 865123.6 ,865038.2 ,864841.1 ,864745.4 ,864429.1 ,864795.6 ,864334.9 > ,864882.0) > > Xcoord=c( 4227640 ,4227816 ,4228929 ,4228508 ,4229569 ,4229498 , > 4226747, > 4226781, 4229597, > 4229204, 4228910, 4228959 ,4229465 ,4229794 ,4229596 ,4229082) > > Lot<-c(1900 , 2000, 2100 , 100 ,200 , 300, 400 , 500 , > 600 , 701 , > 900 , 1000 , 1100, > 300 ,100, 200) > > XYcoord<-spCbind(Ycoord,Xcoord) #doesnt work so > > XYcoord=c(Ycoord,Xcoord) > > TaxLots<-cbind(Ycoord,Xcoord,Lot) > > writeSpatialShape(XYcoord, TaxLots.., > file=data/input/test/Taxlots,strictFilename=FALSE) > > > > So help reading in shape files and then creating them using XY > coordinates > if possible > Any help would be appreciated. Thank you. > > > > > -- > View this message in context: http://www.nabble.com/Reading-and-Creating-Shape-Files-tp26098828p26098828.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > R-help at r-project.org mailing list > 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.