Problems with readOGR
On Wed, 26 Jun 2013, Renger van Nieuwkoop wrote:
Hi
I tried running the following code using the shapefiles for the city of
Zurich
require("rgdal") # requires sp, will use proj.4 if installed
require("maptools")
zh = readOGR(".",layer="Zurich")
and got following error:
OGR data source with driver: ESRI Shapefile
Source: ".", layer: "Zurich"
with 34 features and 6 fields
Feature type: wkbPolygon with 2 dimensions
Fehler in CRS(p4s) : lat_0 = 0 or 90 or alpha = 90
See: http://osgeo-org.1560.x6.nabble.com/Re-Swiss-CORINE-Bessel-1841-Hotine-Oblique-Mercator-Azimuth-Natural-Origin-td3842640.html Here alpha = 90, http://trac.osgeo.org/proj/wiki/GenParms#Parameterlist +alpha ? Used with Oblique Mercator and possibly a few others The resolution in the thread: ogr2ogr shp_dir/ -s_srs epsg:21781 -t_srs epsg:3035 clcbn85p.shp gets from an alternative encoding to LAEA, you may rather need to impose the CRS (delete the offending *.prj file, and impose after reading - but be sure to impose the right CRS). Read the whole thread on the PROJ.4 list, and go back to Cliff Mugnier's Grids & Datums piece in 2001 too. This is a particularly contentious set of projection arguments, and there are many other Oblique Mercator threads on that list. Hope this helps, Roger
ogrInfo gives me this:
ogrInfo(".","Zurich")
Source: ".", layer: "Zurich"
Driver: ESRI Shapefile number of rows 34
Feature type: wkbPolygon with 2 dimensions
Extent: (676227 241585) - (689671 254305.7)
CRS: +proj=omerc +lat_0=46.95240555555556 +lonc=7.439583333333333 +alpha=90 +k=1 +x_0=-9419820.590700001 +y_0=200000 +ellps=bessel +units=m +no_defs
LDID: 87
Number of fields: 6
name type length typeName
1 GMDEQNR 0 7 Integer
2 NR 0 9 Integer
3 NAME 4 45 String
4 GMDE 0 9 Integer
5 FLAECHE_HA 0 9 Integer
6 Quartier 0 4 Integer
I can see that lat_0 is not equal to zero, but don't know how to resolve
this issue.
Thanks in advance for help
Renger
_________________________________________ Renger van Nieuwkoop Centre for Energy Policy and Economics, ETH Z?richbergstrasse 18 (ZUE) CH - 8032 Z?rich +41 44 632 02 63 mailto: rengerv at etzh.ch<mailto:rengerv at etzh.ch> blog.modelworks.ch [[alternative HTML version deleted]]
Roger Bivand Department of Economics, NHH Norwegian School of Economics, Helleveien 30, N-5045 Bergen, Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43 e-mail: Roger.Bivand at nhh.no