Peter; The canonical description of DBase files seems to be
http://www.clicketyclick.dk/databases/xbase/format/ On Tue, 2009-12-01 at 17:28 +0100, Peter Hopfgartner wrote: > Mark Cave-Ayland wrote: > > Peter Hopfgartner wrote: > > > >> Dear PostGIS devels, > >> > >> since we right in the middle of comparing interoperability of shape > >> files between some FOSS programs and ArcGIS, we encoutered also the > >> following: > >> > >> gvSIG chokes on the Bigint as produced by pgsql2shp. Looking at > >> ArcGIs generated files, the max length for numbers is 19, compared to > >> 20 for integers and 32 for floating points as in pgsql2shp. This > >> seems to be confirmed by some Borland tools, when configured for > >> dBase III+. > >> > >> Another limit seems to be that of text fields, that must be no longer > >> then 254. This is the maximum as given by ArcGIS and by the Borland > >> tool. > >> > >> Another point is Boolean: ArcGIS seems to not allow the creation of > >> boolean fields and the Borland Tool ("Database Desktop") says that > >> Booleans have a length of 1. > >> > >> Regards, > >> > >> Peter > > > > Hi Peter, > > > > You've brought up some interesting points here. Can you actually > > clarify these changes with regard to parts of the official shapefile > > spec, or have they been found purely through experimentation? > > > > > > ATB, > > > > Mark. > > > Hi Mark, > > I do still have to figure out, if there are public specs for this. All > I've found is, that attributes should be in data base files which are in > dBase format > (http://www.esri.com/library/whitepapers/pdfs/shapefile.pdf). From the > analysis of the file (and Wikipedia: > http://en.wikipedia.org/wiki/Shapefile), it seems that this should be > dBase III. I do not have any evidence that there is a public spec for > dBase III. > So all we did is basically gather some experimental data, where ArcGIS > and gvSIG are our references. The first, because ESRI introduced the > shape file format and gvSIG, because it is the desktop environment that > we encourage our customers to use. Anyway, we have an old > Borland/Inprise tool ("Database Desktop") here for managing dBase files > and used it for our tests. > > Peter > -- Regards, Chris Hermansen · mailto:[email protected] tel+1.604.714.2878 · fax+1.604.733.0631 · mob+1.778.840.4625 Timberline Natural Resource Group · http://www.timberline.ca 401 · 958 West 8th Avenue · Vancouver BC · Canada · V5Z 1E5 _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
