[R-sig-Geo] Antw: Re: Re: Creating a spatialPolygonsDataFrame from a data frame
Matteo Mattiuzzi
matteo.mattiuzzi at boku.ac.at
Sun Oct 7 19:53:12 CEST 2012
This is what I can serve:
getTile(extent="path/to/your/file.shp")$tile # poly
getTile(extent="path/to/your/raster.file")$tile # rasterfile
getTile(extent=extent("raster.file"))$tile # raster extent
getTile(extent="austria")$tile # charackter name
getTile(extent=list(xmin,xmax,ymin,ymax))$tile #
interactive it is only if you don't give any arguments
I think the only thing what is missing is sp:::bbox (I use raster:::extent) but I coud add it very easily. And the point (I use list(xmin,xmax...))
>>> steven mosher 07.10.12 19.37 Uhr >>>
I looked at that code. I didn't want to do this via interactive map. and I
just wanted a very simple super simple api. getVH(lonlat) or a case that
accepts poly or bbox as input.
On Sun, Oct 7, 2012 at 10:23 AM, Matteo Mattiuzzi <
matteo.mattiuzzi at boku.ac.at> wrote:
> If MODIS tiles are your aim why don't you use?
>
>
> MODIS:::getTile()
>
>
>
> >>> steven mosher 07.10.12 19.11 Uhr >>>
> Well I'm just puttering around and got kinda tired of pulling up Google
> Earth everytime I wanted to locate a MODIS Tile from lat/lon. so I found
> the the following
>
> gring <-"
> http://landweb.nascom.nasa.gov/developers/sn_tiles/sn_gring_10deg.txt"
>
>
>
> GRING <- read.table(gring, skip = 7, stringsAsFactors =FALSE, nrows=648,
> na.strings=c("-999.0000","-99.0000"))
>
> colnames(GRING)<-c("v","h","ll_lon","ll_lat",
> "ul_lon","ul_lat","ur_lon","ur_lat",
> "lr_lon","lr_lat")
>
>
>
>
> On Sun, Oct 7, 2012 at 9:51 AM, Matteo Mattiuzzi <
> matteo.mattiuzzi at boku.ac.at> wrote:
>
> > Hi Steve, what about this?
> >
> >
> > DF <- structure(list(v = c(4L, 4L, 4L, 4L, 4L, 4L, 4L), h = 8:14, ll_lon
> =
> > c(-131.0149,
> > -117.7464, -104.5202, -91.3388, -78.2083, -65.15, -52.1199),
> > ll_lat = c(39.7081, 39.7342, 39.7557, 39.7728, 39.7858, 39.7937,
> > 39.7994), ul_lon = c(-156.8405, -140.7952, -124.8854, -109.0855,
> > -93.3822, -77.7862, -62.229), ul_lat = c(49.8983, 49.9394,
> > 49.9677, 49.9863, 49.9972, 50, 50), ur_lon = c(-140.2398,
> > -124.6153, -109.0021, -93.3968, -77.7506, -62.1191, -46.5357
> > ), ur_lat = c(50.1258, 50.1159, 50.1047, 50.0921, 50.0754,
> > 50.0582, 50.0429), lr_lon = c(-117.2848, -104.2354, -91.191,
> > -78.1497, -65.0781, -52.0094, -38.9707), lr_lat = c(39.8699,
> > 39.8624, 39.8554, 39.8489, 39.8411, 39.8337, 39.828)), .Names = c("v",
> > "h", "ll_lon", "ll_lat", "ul_lon", "ul_lat", "ur_lon", "ur_lat",
> > "lr_lon", "lr_lat"), row.names = 153:159, class = "data.frame")
> >
> >
> >
> >
> > SPDF <- list()
> > id <- matrix(NA,nrow(DF),ncol=2)
> > colnames(id)<- c("h","v")
> > for (u in 1:nrow(DF))
> > {
> > SPDF[[u]] <- Polygons(list(Polygon(cbind(
> > c(DF$ll_lon[u], DF$ul_lon[u], DF$ur_lon[u], DF$lr_lon[u], DF$ll_lon[u]),
> > c(DF$ll_lat[u], DF$ul_lat[u], DF$ur_lat[u], DF$lr_lat[u], DF$ll_lat[u])),
> > hole = FALSE)),u)
> > id[u,] <- c(DF$h[u], DF$v[u]) # probably h/v information can be taken
> > direcly from DF
> > }
> > SPDF <-
> SpatialPolygons(SPDF,1:length(SPDF),proj4string=CRS("+proj=longlat
> > +ellps=WGS84 +datum=WGS84 +no_defs"))
> > SPDF <- SpatialPolygonsDataFrame(SPDF,
> > as.data.frame(id),match.ID=FALSE)
> > plot(SPDF,col="green")
> >
> >
> >
> >
> > >>> steven mosher 07.10.12 8.18 Uhr >>>
> > Hi,
> >
> > I have a dataframe that has a few hundred rows like this.
> >
> > DF <- structure(list(v = c(4L, 4L, 4L, 4L, 4L, 4L, 4L), h = 8:14, ll_lon
> =
> > c(-131.0149,
> > -117.7464, -104.5202, -91.3388, -78.2083, -65.15, -52.1199),
> > ll_lat = c(39.7081, 39.7342, 39.7557, 39.7728, 39.7858, 39.7937,
> > 39.7994), ul_lon = c(-156.8405, -140.7952, -124.8854, -109.0855,
> > -93.3822, -77.7862, -62.229), ul_lat = c(49.8983, 49.9394,
> > 49.9677, 49.9863, 49.9972, 50, 50), ur_lon = c(-140.2398,
> > -124.6153, -109.0021, -93.3968, -77.7506, -62.1191, -46.5357
> > ), ur_lat = c(50.1258, 50.1159, 50.1047, 50.0921, 50.0754,
> > 50.0582, 50.0429), lr_lon = c(-117.2848, -104.2354, -91.191,
> > -78.1497, -65.0781, -52.0094, -38.9707), lr_lat = c(39.8699,
> > 39.8624, 39.8554, 39.8489, 39.8411, 39.8337, 39.828)), .Names =
> c("v",
> > "h", "ll_lon", "ll_lat", "ul_lon", "ul_lat", "ur_lon", "ur_lat",
> > "lr_lon", "lr_lat"), row.names = 153:159, class = "data.frame")
> >
> >
> > The columns are v and h, two attributes, and then 4 points in lat and
> > lon ll_lon is lower left lon, lr_lon is lower right,
> > ul_lon is upper left and ur_lon is upper right.
> >
> > What I want to do is create a spatialPolygonsDataFrame from this data.
> > As best as I can figure I have to take the lon/lat coordinates and put
> > them in to a matrix format, replicate the first point to close
> > the ring and create a Polygon, and then Create a Polygons() object with
> an
> > ID and then a SpatialPolygon, and then a
> > SpatialPolygonDataFrame from a list of the spatial polygons.
> >
> > What I'm struggling with is how to do this for the several hundred rows
> > that I have.
> >
> > Steve
> >
> > [[alternative HTML version deleted]]
> >
> > _______________________________________________
> > R-sig-Geo mailing list
> > R-sig-Geo at r-project.org
> > https://stat.ethz.ch/mailman/listinfo/r-sig-geo
> >
> >
> >
>
>
>
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