Hi Michaël,
The approach I'm taking to reach the same goal is quite different. If it
works, the modification will only be in one method:
ShapefileWriter.writeDbf(FeatureCollection featureCollection, String
fname). What I intend is to read fname's dbf header using DbfFile(String
file), if the file exists, and use the DbfFieldDefs contained within. At
this point I don't know when the "Replace existing file" dialog occurs, and
if it deletes it before writeDbf is called. Do you see any other pitfalls
of this approach?
regards,
Larry
2010/6/22 Michaël Michaud <michael.mich...@free.fr>
> Hi Larry,
>
> As you go on working about this feature, I just want to let you know the
> work I did in 2004 to add new attribute types in JUMP
> You'll find a patch and a complete doc here :
> http://michael.michaud.free.fr/jump/plugins/plugins.html (hoping you can
> read french)
> My concern was exactly "not to change input schema". I abandonned it
> because my concern changed, and because I could not update every piece
> of JUMP code that should have been updated to take new attribute types
> into account (especially database-access, but not only).
>
> Michaël
>
> Larry Becker a écrit :
> > I agree with Michaël. This isn't really a bug, but it is annoying to
> > have your DBF header modified. I have already spent some time trying
> > to implement a "don't modify the DBF header" approach to
> > SaveSelectedDatasets, but it seems to be a difficult modification and
> > I haven't gotten very far on it yet. The idea is to read the existing
> > header and associate with the attributes being saved (by name)
> > whenever possible, and convert using custom format specifiers.
> >
> > I'll keep working on it because this is an important feature since
> > shape files are OJ's primary dataset.
> >
> > regards,
> > Larry
> >
> > 2010/6/22 Michaël Michaud <michael.mich...@free.fr
> > <mailto:michael.mich...@free.fr>>
> >
> > Hi,
> >
> > Would be interesting to have more details.
> > Different bytes surrounded in your pdf file is related to a recent
> > discussion with Larry on the forum.
> >
> > OpenJUMP does not support length/decimal count in attribute
> > definition.
> > It exports :
> > integers to 11 bytes long dbf field (thanks to Larry who reduced
> > it from
> > 16 to 11)
> > doubles to 33 bytes long dbf field including 16 decimal digits (hence
> > the 21 10 bytes from OJ dbf instead of 0c 03 which means 12 bytes
> > including 3 decimal digit)
> >
> > It is not easy to workaround this, but it can not considered as a
> bug.
> > OpenOffice.org calc can read these files very well and write the
> field
> > length this way :
> > before :
> > poiShapeID,N,4,0 poiTypID,N,4,0 poiName,C,50
> >
> > after
> > poiShapeID,N,11,0 poiTypID,N,11,0 poiName,C,32
> >
> >
> > Notice that the character field has also been changed because
> > there were
> > no field with more than 32 characters in the dataset
> >
> > If OpenJUMP dbf cannot be uploaded to access with Borland-BDE, I
> > suppose
> > there is another problem.
> > I do not understand what is the matter with the length of file names.
> >
> > my 2 cents
> >
> > Michaël
> >
> >
> >
> > Stefan Steiniger a écrit :
> > > Hei All/Developers,
> > >
> > > I got an email from Bernd describing the following problem with
> > > OpenJUMP writing shape/dbf files. [my translation]:
> > >
> > > =============
> > > It seem like the dbf headers written by OpenJUMP are not conform to
> > > the DBASE III standard.
> > >
> > > Working with Borland-BDE dbase-tests failed and an Error 8961 is
> > > returned. The BDE was/is actually used to include the dbf files
> > into a
> > > MS Access database - in particular as the BDE supports long file
> > names.
> > >
> > > With short file names the BDE is not used and hence there are no
> > > problems, also other programs don't seem to test for the correct
> dbf
> > > header. but... short filenames are not so comfortable, etc.
> > >
> > > Attached is a file (hexdump_dbf.pdf) that shows the differences
> > before
> > > and after OJ writes the shape file - and the changes in the header.
> > >
> > > The saved file contains several spaces and quite a bit of digits
> > after
> > > the comma [sound very similar to what Michael looked into lately?]
> -
> > > hence the file size is bigger too.
> > >
> > > ==============
> > >
> > > Anyone who is interested in fixing that or has any suggestions?
> > >
> > > the dbase standard description is also attached
> > >
> > > mhm.. I actually would not be surprised when the original shape
> file
> > > writer is from the 90ies
> > >
> > > stefan
> > >
> > > -------- Original Message --------
> > > Subject: OpenJump, Shape und Dbase
> > > Date: Thu, 17 Jun 2010 13:41:52 +0200
> > > From: <bernd.we...@erfurt.de <mailto:bernd.we...@erfurt.de>>
> > > To: <sst...@geo.uzh.ch <mailto:sst...@geo.uzh.ch>>
> > >
> > >
> > >
> > > Hallo Stefan,
> > >
> > > Im speziellen Fall geht es um die numerischen Datenfelder (Typ
> > double)
> > > aus den DBF-Dateien, die nicht ganz den Spezifikationen von
> > DBASE III
> > > genügen. Mitbekommen habe ich das bei Einsatz der Borland-BDE,
> > die den
> > > Header offensichtlich genau prüft und einen Fehler 8961 meldet.
> > >
> > > Viele Programme scheint die Veränderung des Headers nicht zu
> > stören, die
> > > BDE schon. Zur Erinnerung: Ich habe die BDE ausprobiert, um die
> > DBFs aus
> > > den SHAPES in eine MS-ACCESS-Datenbank einzubinden, weil die BDE
> > auch
> > > lange Dateinamen unterstützt. ACCESS deswegen, weil ich dort mit
> > > einfachen Abfragen aus Sachdatenbanken (Informix) die Geodaten
> > ergänzen
> > > und aufwerten kann.
> > >
> > > Mit kurzen Dateinamen brauche ich die BDE nicht, habe keine
> > Probleme mit
> > > ACCESS, aber GIS mit kurzen Dateinamen sieht recht komisch aus.
> > >
> > > Hier nun meine Forschungsergebnisse:
> > >
> > > 1. Daten im Originalzustand in File hexdump_ok.pdf
> > > hier ist nach den Datentypen N=Numerical zu erkennen, daß die
> > Feldgrößen
> > > sich in typischen Werten bewegen.
> > > 2. Daten im File hexdump_err.pdf
> > > Nach "Speichern unter …" im Openjump sind diese Eintragungen
> > deutlich
> > > anders und die numerischen Werte haben führende Leerzeichen und
> ganz
> > > viele Nachkommastellen.
> > >
> > > Dieses Verhalten erklärt auch, warum Fremddaten nach Bearbeitung
> > mit OJ
> > > mehr Speicherplatz brauchen als im Original.
> > >
> > > Die DBASE-Spezifikationen habe ich Dir als 3. Datei angehängt.
> > >
> > > In der Hoffnung, daß Du jemanden findest, der das Problem lösen
> > kann,
> > > verbleibe ich mit vielen Grüßen aus dem sonnigen Thüringen.
> > >
> > > Bernd Wehle
> > > Tiefbau- und Verkehrsamt Erfurt
> > > 99085 Erfurt, Steinplatz1
> > > Tel.: 0361 655 3108
> > > Fax: 0361 655 3178
> > > e-Mail: ___bernd.we...@erfurt.de_ <mailto:bernd.we...@erfurt.de
> > <mailto:bernd.we...@erfurt.de>>
> > >
> > > <<hexdump_ok.pdf>> <<hexdump_err.pdf>> <<dbase_strukturen.pdf>>
> > >
> > >
> >
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