[R-sig-Geo] Import from Geodatabase

[Roger Bivand]

On Mon, 13 Jun 2011, afischbach wrote:

> For shape files the package maptools has worked for me.
>
> require(rgdal)
> require(maptools)
>
> prj <- CRS("+proj=aeqd +lat_0=70 +lon_0=-170")  #Azimuthal Equadistant -170,
> 70
> fileName <- 'YourShapeFile.shp'
> shape=readShapeLines(fileName, proj4string=prj, verbose=FALSE, repair=FALSE,
> delete_null_obj=FALSE)
>
> For ASCII rasters the package sp works well.
>
> require (sp)
> map <- readGDAL( 'Your_ASCII_raster.asc')
>
> Being able to pull in ArcGIS personal geodatabase features would be nice to
> do.

As you may be aware, personal geodatabase are MS Access-based objects, and 
are being replaced by ESRI with file-geodatabase solutions (if I 
understand correctly). There is no effective cross-platform support for 
personal geodatabases anywhere, and in practice they are very bloated, 
contain multiple copies of the same information, and generally not 
portable. For interfacing any other software than ESRI on the same 
platform and architecture, they are not a helpful solution, and the open 
source world has abandoned attempts to try to reverse engineer them - see 
notes in the OGR part of GDAL as implemented in rgdal.

As ESRI moves towards openly documented data storage standards, we may be 
able to interface more easily, for example, ESRI now used GDAL for reading 
and writing rasters for which it doesn't have its own support, and is 
active in improving code. So look at the drivers available in rgdal for 
raster and vector objects in rgdal: ogrDrivers() and gdalDrivers(), and 
export data from Arc in those formats if you want to avoid unnecessary 
delay; think workflow before committing to a choice of format.

Roger

>
> -----
> Tony Fischbach, Wildlife Biologist
> Walrus Research Program
> Alaska Science Center
> U.S. Geological Survey
> 4210 University Drive
> Anchorage, AK 99508-4650
>
> AFischbach at usgs.gov
> http://alaska.usgs.gov/science/biology/walrus
> --
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>
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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.Bivand at nhh.no