Re: [R-sig-Geo] SpatialPointsDataFrame into GRASS problems

Roger Bivand Tue, 03 Aug 2010 05:33:40 -0700

On Tue, 3 Aug 2010, stephen sefick wrote:

I am new to sp objects and this seems more convienint than qgis ->
shapefile -> import into GRASS.  I am having a problem getting the
data from a spatial points dataframe into grass.  Below is the code.
Any help would be appreciated.

Please provide the data as an RData file, not as a broken dput. Pleaseprovide this (and your code, simplified if possible - there may be otherproblems in creating the SpatialPointsDataFrame) on a web server ifpossible. Please also indicate how your GRASS location is defined (outputof gmeta6() for example).

Note that the OGR Shapefile driver does not permit variable names of over10-11 characters.


Roger


z <- (dput(ftbr_UTM)
structure(list(site = c("Jennie_Creek_Main_Stem", "Jennie_Creek_Main_Stem",
"Wolf_Pit_Creek_Main_Stem", "Wolf_Pit_Creek_Main_Stem",
"Little_Rockfish_Main_Stem_North",
"Little_Rockfish_Main_Stem_North", "Big_Muddy_Creek_Main_Stem",
"Big_Muddy_Creek_Main_Stem", "Flat_Creek_Main_Stem", "Flat_Creek_Main_Stem",
"little_river_tributary", "little_river_tributary", "Hector_Creek_Main_Stem",
"Hector_Creek_Main_Stem", "Juniper_Creek_Main_Stem", "Juniper_Creek_Main_Stem",
"Field_Branch_Main_Stem", "Field_Branch_Main_Stem", "Gum_Branch_Main_Stem",
"Gum_Branch_Main_Stem"), base = c("ftbr", "ftbr", "ftbr", "ftbr",
"ftbr", "ftbr", "ftbr", "ftbr", "ftbr", "ftbr", "ftbr", "ftbr",
"ftbr", "ftbr", "ftbr", "ftbr", "ftbr", "ftbr", "ftbr", "ftbr"
), creek = c("jcms", "jcms", "wpms", "wpms", "lrf1", "lrf1",
"bmcm", "bmcm", "fcms", "fcms", "lrtb", "lrtb", "hcms", "hcms",
"jpms", "jpms", "fbms", "fbms", "gbms", "gbms"), date = c("06/20/2010",
"06/20/2010", "06/20/2010", "06/20/2010", "06/18/2010", "06/18/2010",
"06/18/2010", "06/18/2010", "06/21/2010", "06/21/2010", "06/22/2010",
"06/22/2010", "06/22/2010", "06/22/2010", "06/21/2010", "06/21/2010",
"06/19/2010", "06/19/2010", "06/19/2010", "06/19/2010"), elevation_m = c(101,
101, 81, 81, 59, 59, 75, 75, 73, 73, 55, 55, 55, 55, 88, 88,
77, 77, 87, 87), x = c(652159, 652040, 651646, 651533, 674147,
674116, 635466, 635326, 665726, 665676, 675295, 675362, 673098,
673159, 658917, 658918, 655613, 655464, 651748, 651553), y = c(3887647,
3887758, 3886986, 3886870, 3893724, 3893581, 3876272, 3876145,
3893886, 3893742, 3895529, 3895663, 3895076, 3895261, 3882474,
3882663, 3881587, 3881591, 3884249, 3884280), station = c(1,
6, 1, 6, 1, 6, 1, 6, 1, 6, 1, 6, 1, 6, 1, 6, 1, 6, 1, 6), notes_ = c(NA,
NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA,
NA, NA, NA)), .Names = c("site", "base", "creek", "date", "elevation_m",
"x", "y", "station", "notes_"), class = "data.frame", row.names = c("1",
"2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12", "13",
"14", "15", "16", "17", "18", "19", "20")))


utm2points <- function(data, x_coord="x", y_coord="y", coord_string=NULL){

#utm 17
#+proj=utm +zone=17 +ellps=GRS80 +units=m +no_defs

#utm 16
#+proj=utm +zone=16 +ellps=GRS80 +units=m +no_defs

require(rgdal)

#get x y
coord <- c(x_coord, y_coord)
x_y <- data[,charmatch(coord, colnames(data))]

#get everything else
dater <- data[,-charmatch(coord, colnames(data))]

#make Spatial Data Frame
Point_vector <- SpatialPointsDataFrame(x_y, dater, proj4string =
CRS(coord_string))
return(Point_vector)
}


z <- utm2points(ftbr_UTM, coord_string="+proj=utm +zone=17
+ellps=GRS80 +units=m +no_defs")


#and then I try to import this into GRASS with

writeVECT6(z, "ftbr_2010_sampling_points")

#and get the following error

Error in writeOGR(SDF, dsn = rtmpfl1, layer = shname, driver = "ESRI
Shapefile") :

        GDAL Error 1: Invalid index : -1
In addition: Warning message:
In writeOGR(SDF, dsn = rtmpfl1, layer = shname, driver = "ESRI Shapefile") :

        Non-fatal GDAL Error 6: Normalized/laundered field name:
'elevation_m' to 'elevation_'




--
Stephen Sefick
____________________________________
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|___________________________________|
| sas0...@auburn.edu                             |
| http://www.auburn.edu/~sas0025             |
|___________________________________|

Let's not spend our time and resources thinking about things that are
so little or so large that all they really do for us is puff us up and
make us feel like gods.  We are mammals, and have not exhausted the
annoying little problems of being mammals.

                                -K. Mullis

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--
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Helleveien 30, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
e-mail: roger.biv...@nhh.no

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Re: [R-sig-Geo] SpatialPointsDataFrame into GRASS problems

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