[R-sig-Geo] convert a shapefile to geotiff with type = "Float32"

Tue Feb 9 11:56:19 CET 2010

I can tell that I have also a problem writting NA values in map exported
through rgdal (with several drivers, e.g., IDRISI) and imported in
ArcInfo. The NA values are not properly imported, and at the moment I'm
exporting NA values as a number (e.g., -9999)

Javier
---

> Hello again,
> My writeGDAL statement was slightly wrong.. I didn't have the NA
> values in quotes.
> it should be:
> # attempt to write out a geotiff
>  writeGDAL(shp.grd, "/home/data2/gis/AT_Hailey/r_rasters/test.tif",
> drivername = "GTiff", type = "Float32", mvFlag = 'NA', options=NULL,
> copy_drivername = "GTiff")
>
> I can now load the tiff file into QGis correctly, but still not ArcMap.
> Has anyone found a grid type that loads into Arc smoothly?
> Hailey
>
>
> On Mon, Feb 8, 2010 at 11:56 AM, Hailey Eckstrand
> <haileyeckstrand at gmail.com> wrote:
>> Hello List,
>> I am trying to load in a shapefile and then write it out as a geoTiff.
>> I am using the package rgdal.
>>
>> library("rgdal")
>> ## load in my shapefile
>> shp <-
>> readOGR("/home/data3/projects/hydrology/vic/output/water_balance/peace_cc/summary",
>> "peace_base_et_6190")
>>
>> # Just to be clear, here is the structure of my data
>> str(shp)
>> Formal class 'SpatialPointsDataFrame' [package "sp"] with 5 slots
>>  ..@ data       :'data.frame': 3975 obs. of  13 variables:
>>  .. ..$ jan: num [1:3975] 12 12.4 12.3 12.3 12.5 ...
>>  .. ..$ feb: num [1:3975] 12.8 13.2 13 13.1 13.5 ...
>>  .. ..$ mar: num [1:3975] 16.3 16.6 16.8 16.8 17.1 ...
>>  .. ..$ apr: num [1:3975] 31.2 33.7 30.1 28.1 29.2 ...
>>  .. ..$ may: num [1:3975] 106 111 101 99 103 ...
>>  .. ..$ jun: num [1:3975] 99.4 116 121.1 115.1 108 ...
>>  .. ..$ jul: num [1:3975] 57.8 56.9 74.7 69.5 65 ...
>>  .. ..$ aug: num [1:3975] 53.8 51.2 59.5 58.6 57.3 ...
>>  .. ..$ sep: num [1:3975] 44 40.6 52.8 49.4 49.2 ...
>>  .. ..$ oct: num [1:3975] 32.4 32 35.3 34.1 34.9 ...
>>  .. ..$ nov: num [1:3975] 12.6 12.9 12.9 12.9 13.4 ...
>>  .. ..$ dec: num [1:3975] 12.8 13.2 13.2 13.1 13.6 ...
>>  .. ..$ sum: num [1:3975] 491 510 542 522 517 ...
>>  ..@ coords.nrs : num(0)
>>  ..@ coords     : num [1:3975, 1:2] -123 -123 -122 -123 -123 ...
>>  .. ..- attr(*, "dimnames")=List of 2
>>  .. .. ..$ : NULL
>>  .. .. ..$ : chr [1:2] "coords.x1" "coords.x2"
>>  ..@ bbox       : num [1:2, 1:2] -127.7 54.2 -120.6 58
>>  .. ..- attr(*, "dimnames")=List of 2
>>  .. .. ..$ : chr [1:2] "coords.x1" "coords.x2"
>>  .. .. ..$ : chr [1:2] "min" "max"
>>  ..@ proj4string:Formal class 'CRS' [package "sp"] with 1 slots
>>  .. .. ..@ projargs: chr " +proj=longlat +ellps=WGS84 +datum=WGS84
>> +no_defs +towgs84=0,0,0"
>>
>> # Convert it to a SpatialGridDataGrame, so I can writeGDAL
>> gridded(shp) <- TRUE
>> shp.grid <- as(shp, "SpatialGridDataFrame")
>>
>> # structure of my SpatialGridDataFrame
>> str(shp.grid)
>> Formal class 'SpatialGridDataFrame' [package "sp"] with 6 slots
>>  ..@ data       :'data.frame': 7130 obs. of  13 variables:
>>  .. ..$ jan: num [1:7130] NA NA NA NA NA NA NA NA NA NA ...
>>  .. ..$ feb: num [1:7130] NA NA NA NA NA NA NA NA NA NA ...
>>  .. ..$ mar: num [1:7130] NA NA NA NA NA NA NA NA NA NA ...
>>  .. ..$ apr: num [1:7130] NA NA NA NA NA NA NA NA NA NA ...
>>  .. ..$ may: num [1:7130] NA NA NA NA NA NA NA NA NA NA ...
>>  .. ..$ jun: num [1:7130] NA NA NA NA NA NA NA NA NA NA ...
>>  .. ..$ jul: num [1:7130] NA NA NA NA NA NA NA NA NA NA ...
>>  .. ..$ aug: num [1:7130] NA NA NA NA NA NA NA NA NA NA ...
>>  .. ..$ sep: num [1:7130] NA NA NA NA NA NA NA NA NA NA ...
>>  .. ..$ oct: num [1:7130] NA NA NA NA NA NA NA NA NA NA ...
>>  .. ..$ nov: num [1:7130] NA NA NA NA NA NA NA NA NA NA ...
>>  .. ..$ dec: num [1:7130] NA NA NA NA NA NA NA NA NA NA ...
>>  .. ..$ sum: num [1:7130] NA NA NA NA NA NA NA NA NA NA ...
>>  ..@ grid       :Formal class 'GridTopology' [package "sp"] with 3 slots
>>  .. .. ..@ cellcentre.offset: Named num [1:2] -127.7 54.2
>>  .. .. .. ..- attr(*, "names")= chr [1:2] "coords.x1" "coords.x2"
>>  .. .. ..@ cellsize         : Named num [1:2] 0.0625 0.0625
>>  .. .. .. ..- attr(*, "names")= chr [1:2] "coords.x1" "coords.x2"
>>  .. .. ..@ cells.dim        : Named int [1:2] 115 62
>>  .. .. .. ..- attr(*, "names")= chr [1:2] "coords.x1" "coords.x2"
>>  ..@ grid.index : int(0)
>>  ..@ coords     : num [1:2, 1:2] -127.7 -120.6 54.2 58
>>  .. ..- attr(*, "dimnames")=List of 2
>>  .. .. ..$ : NULL
>>  .. .. ..$ : chr [1:2] "coords.x1" "coords.x2"
>>  ..@ bbox       : num [1:2, 1:2] -127.8 54.2 -120.6 58.1
>>  .. ..- attr(*, "dimnames")=List of 2
>>  .. .. ..$ : chr [1:2] "coords.x1" "coords.x2"
>>  .. .. ..$ : chr [1:2] "min" "max"
>>  ..@ proj4string:Formal class 'CRS' [package "sp"] with 1 slots
>>  .. .. ..@ projargs: chr " +proj=longlat +ellps=WGS84 +datum=WGS84
>> +no_defs +towgs84=0,0,0"
>>
>> # attempt to write out a geotiff
>> writeGDAL(shp.grd, "/home/data2/gis/AT_Hailey/r_rasters/test.tif",
>> drivername = "GTiff", type = "Float32", mvFlag = NA, options=NULL,
>> copy_drivername = "GTiff")
>>
>>
>> The file that I write out only has NA values. I realize something is
>> wrong as I haven't figured out how to define which column I'd like to
>> convert.
>> Thanks in advance,
>> Hailey
>>
>
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