It would be informative to try ogrInfo from the shell prompt (i.e., outside of
R) to find out if this is an R problem or an ogrInfo problem.
-Don
--
Don MacQueen
Lawrence Livermore National Laboratory
7000 East Ave., L-627
Livermore, CA 94550
925-423-1062
On 3/4/17, 3:40 AM, "R-SIG-Mac on behalf of D G. Rossiter"
<r-sig-mac-boun...@r-project.org on behalf of d.g.rossi...@cornell.edu> wrote:
Thanks to Ken Beath, this indeed was the problem. I tested by formatting a
USB drive to Mac format with Disk Info, copying the shapefiles onto it, and
then reading with readOGR().
Problem solved, although the Mac-formatted USB drive could not be used to
transfer files to and from Windows machines.
D G (David) Rossiter
Section of Soil & Crop Sciences
Cornell University
http://www.css.cornell.edu/faculty/dgr2/
1. Re: Mac-only problem using readOGR(), which uses ogrInfo(),
to read a shapefile from a directory on a USB pen drive (Ken Beath)
From: Ken Beath <k...@kjbeath.com.au<mailto:k...@kjbeath.com.au>>
Subject: Re: [R-SIG-Mac] Mac-only problem using readOGR(), which uses
ogrInfo(), to read a shapefile from a directory on a USB pen drive
Date: 3 March 2017 at 20:28:33 GMT-5
To: "D G. Rossiter"
<d.g.rossi...@cornell.edu<mailto:d.g.rossi...@cornell.edu>>
Cc: "r-sig-mac@r-project.org<mailto:r-sig-mac@r-project.org>"
<r-sig-mac@r-project.org<mailto:r-sig-mac@r-project.org>>
My thought is that it might be that USB drives are usually MSDOS formatted.
Usually not a problem but rgdal works with directories. Formatting in a Mac
with Disk Utility might be a work-around, with the limitation that the USB will
only work in Macs.
I would also try verbose=TRUE which may give more information.
In the absence of other ideas contacting the package author can help.
Ken
On 4 Mar 2017, at 3:32 am, D G. Rossiter
<d.g.rossi...@cornell.edu<mailto:d.g.rossi...@cornell.edu>> wrote:
I ran across a Mac-only problem using readOGR(), which uses ogrInfo(), to
read a shapefile from a directory on a USB pen drive. I tested the behaviour on
a Windows 10 machine and did not get the problem.
Trying to read from the USB drive, with relative and full paths:
setwd("/Volumes/ISPRS/“) # this is my connected USB drive
list.files()
[1] "map7100.dbf" "map7100.prj"
[3] "map7100.sbn" "map7100.sbx"
[5] "map7100.shp" "map7100.shp.xml"
[7] "map7100.shx"
file.exists("map7100.shp")
[1] TRUE
usa <- readOGR(dsn=".", layer="map7100")
Error in ogrInfo(dsn = dsn, layer = layer, encoding = encoding, use_iconv =
use_iconv, :
Cannot open data source
usa <- readOGR(dsn="/Volumes/ISPRS", layer="map7100")
Error in ogrInfo(dsn = dsn, layer = layer, encoding = encoding, use_iconv =
use_iconv, :
Cannot open data source
But, readOGR reads the shapefile correctly if it’s located on the Mac’s
internal drive:
setwd("/Users/rossiter/data/edu/dgeostats/ex")
file.exists("./ds/NEweather/map7100.shp")
[1] TRUE
usa <- readOGR(dsn="./ds/NEweather", layer="map7100")
OGR data source with driver: ESRI Shapefile
Source: "./ds/NEweather", layer: "map7100"
with 7926 features
It has 19 fields
All packages are up to date. Here is the sessionInfo():
R version 3.3.2 (2016-10-31)
Platform: x86_64-apple-darwin13.4.0 (64-bit)
Running under: OS X El Capitan 10.11.6
locale:
[1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8
attached base packages:
[1] stats graphics grDevices utils datasets methods base
other attached packages:
[1] ggplot2_2.2.1 sf_0.3-4 maptools_0.9-1 rgdal_1.2-5
[5] sp_1.2-4 gstat_1.1-4
loaded via a namespace (and not attached):
[1] Rcpp_0.12.9 plyr_1.8.4 xts_0.9-7 tools_3.3.2
[5] digest_0.6.12 evaluate_0.10 tibble_1.2 gtable_0.2.0
[9] lattice_0.20-34 DBI_0.5-1 yaml_2.1.14 stringr_1.2.0
[13] knitr_1.15.1 rprojroot_1.2 grid_3.3.2 spacetime_1.2-0
[17] foreign_0.8-67 rmarkdown_1.3 udunits2_0.13 magrittr_1.5
[21] backports_1.0.5 scales_0.4.1 intervals_0.15.1 htmltools_0.3.5
[25] units_0.4-2 rsconnect_0.7 assertthat_0.1 colorspace_1.3-2
[29] labeling_0.3 stringi_1.1.2 lazyeval_0.2.0 munsell_0.4.3
[33] FNN_1.1 zoo_1.7-14
This is a problem because several of my students have OS/X machines and
like to work from USB-connected external drives.
D G (David) Rossiter
Section of Soil & Crop Sciences
Cornell University
http://www.css.cornell.edu/faculty/dgr2/
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