On Thu, 18 Mar 2010, Robert J. Hijmans wrote:
I believe that this is part of the DBF specification (there is also a
limit on the number of characters in a variable name. 12?). This was
largely ignored by ArcView (and the versions of excel that write dbf
files), but apparently not by ArcGIS (apart from the missing warning
message, that is probably a good thing). Perhaps a future version of
readOGR could check for and fix variable names that are not DBF
compliant when writing shp files?
Since OGR uses drivers, incorporating lots of driver-specific fixes is not
a practical solution, as many others accept field names that DBF chokes
on. If I get a well-tested patch in R for writeOGR() with no side-effects,
I might consider it. There is C code in foreign/src/Rdbfwrite.c, but I
think that it will permit a leading underscore - it crops to 11 characters
plus a closing \0. The only driver-specific check in writeOGR() now is to
to warn when KML files not in geographical coordinates are written.
Roger
Robert
On Thu, Mar 18, 2010 at 9:40 AM, Wayne Richter
<[email protected]> wrote:
This should indeed be the problem. From the Help: "Field names must start with a
letter. Field names must contain only letters, numbers, and underscores."
Unfortunately, ESRI software can behave in a cryptic, inconsistent or unhelpful way when
it encounters a field name that it doesn't like. A hidden trailing space can really mess
you up.
Wayne Richter
New York State Department of Environmental Conservation
625 Broadway
Albany, New York 12233-4756
518-402-8974
From: "Robert J. Hijmans" <[email protected]>
To: caspar hallmann <[email protected]>
CC: r-sig-geo <[email protected]>
Date: 3/18/2010 12:30 PM
Subject: Re: [R-sig-Geo] writeOGR issue in dbf
I think the problem is an illegal variable name "dist.m"
This works for me:
data(meuse)
coordinates(meuse)=~x+y
names(meuse)[12] = 'distm'
writeOGR(meuse,".","test",driver="ESRI Shapefile")
Robert
On Thu, Mar 18, 2010 at 9:26 AM, Roger Bivand <[email protected]> wrote:
On Thu, 18 Mar 2010, caspar hallmann wrote:
Dear list,
I am using writeOGR to create an ESRI shapefile from a
SpatialPointsDataFrame. When opening the shapefile in ArcMap and ask
for the attributes, I get an error "A column was specified that does
not exist".
I only have other tools using OGR (GRASS, QGIS) and Excel 2003 SP3 on
Windows XP. Your example cannot be reproduced using those. I suspect from
trying to interpret the entrails of ESRI "help", that an integer column is
required reproducing the FID values already encoded in the *.shp. Try:
meuse$FIDs <- 1:nrow(meuse)
and write out again. This doesn't match your simple copying to get it to
read, though. If others could comment who have access to Arc (which
version), that would be useful. Please include a copy of the messages
displayed when rgdal is loaded, so that we have control of the versions.
Does changing locale make a difference?
Roger
Similarly, when opening the dbf of the shapefile in Paradox I get
"Unable to open table. Corrupt table/index header".
This does not only happen to my own Dataset but also the meuse data.
data(meuse)
coordinates(meuse)=~x+y
class(meuse)
writeOGR(meuse,".","test",driver="ESRI Shapefile")
# then try ArcMap or Paradox fails as mentioned above.
#Strangely, when i do
write.dbf(read.dbf("test.dbf"),file="test2")
#then renaming test2 into test, my attribute tables open up fine, and
Paradox stops complaining.
any clues?
Caspar.
sessionInfo()
R version 2.10.1 (2009-12-14)
i386-pc-mingw32
locale:
[1] LC_COLLATE=Dutch_Netherlands.1252 LC_CTYPE=Dutch_Netherlands.1252
LC_MONETARY=Dutch_Netherlands.1252 LC_NUMERIC=C
[5] LC_TIME=Dutch_Netherlands.1252
attached base packages:
[1] stats graphics grDevices utils datasets methods base
other attached packages:
[1] pscl_1.03.3 coda_0.13-4 mvtnorm_0.9-9
automap_1.0-5 MASS_7.3-5 lme4_0.999375-32
Matrix_0.999375-33 maptools_0.7-29
[9] lattice_0.18-3 foreign_0.8-39 raster_0.9.9-24
rgdal_0.6-24 gstat_0.9-66 sp_0.9-57
loaded via a namespace (and not attached):
[1] grid_2.10.1 tools_2.10.1
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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: [email protected]
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https://stat.ethz.ch/mailman/listinfo/r-sig-geo
_______________________________________________
R-sig-Geo mailing list
[email protected]
https://stat.ethz.ch/mailman/listinfo/r-sig-geo
--
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: [email protected]
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