Toni, The entire purpose of the dbf file in the ESRI model is to hold the attributes for the shapes in the shape file. Why would you create a NULL shape just to hold data? That stands to reason that you NEED a separate database file.
What I have that is different is a set of shape files with each having a one to one relationship with data in its dbf file. I also have some "related" data in "extra" dbf files that I tie to the other data using a sql query. I can use the query because I've added it all to postgres. I think the misunderstanding for me is that you would have data not corresponding to a shape. My apologies if this is a practice that I haven't heard of before. Gail -- Things are only difficult while you don't understand them. >From: "toni" <fiorenontaglio at libero.it> >To: "pmapper mailing list" <pmapper-users at faunalia.it> >Subject: [Pmapper-users] R: attribute query and records with no geometry >Date: Fri, 26 May 2006 23:03:04 +0200 > >I think we're misunderstanding... > >I don't have an external dbf file to tie. >I'm talking about the *shape dbf* file (shp shx -->dbf<--): >this file contains records not linked to the geometry in the related shp >file. Infact all the geometries have their own data but there are plenty >data without a geometry (these are no spatial data, not linkable to the >geometries). Files are not corrupted because they're intentionally made in >this way. > >No spatial data are useful for me because when you search for them you >should have the answer: data + "unlocatable". > >Gail Long told me he added a search function to parse the shape dbf >searching for records without geometry tie, then he migrated to postgis & >postgres because search was faster. > >Any other suggestion? >thanks in advance, bye > > > > >----- Original Message ----- >From: Armin Burger >To: Gail Long >Cc: fiorenontaglio at libero.it ; pmapper-users at faunalia.it >Sent: Wednesday, May 24, 2006 11:18 PM >Subject: Re: [Pmapper-users] attribute query and records with no geometry > > >Just a more general remark using dbf files and querying them with PHP: >If for whatever reasons whatsoever you need to use them and not putting >the data into a real DB, on Windows you can speed up things via ODBC. If >you have MS Access, just define an MDB and link the dBase files to it as >external data source. Then access the MDB via the ODBC driver. Works >*much* faster than native dbf functions. > >Another remark for shapefiles and dbf: If you modify the dbf part of a >shapefile with pure dBase functions/programs, and add or remove records, >you might get into trouble sooner or later with a corrupt shapefile that >is not readable any more. > >Armin > >Gail Long wrote: > > Tony, > > > > A layer is made up of shape files for geometry and data in the dbf files >for > > attributes. If there is no tie to the geometry there are no records to >be > > returned. > > > > However, I had a similar need and know that what you want to do can be >done. > > I have several .dbf files that have lots of useful data in them. For >the > > most part I've been able to use a pmapper JOIN and tie the data uniquely >to > > a record in a shape file ( a feature) by adding a key field to the dbf > > tables that links back to my Postgres tables. This should work the same >way > > with shape files and link back to an attribute. > > > > With two of the tables however, I don't have a clean way to join them to >a > > geographic feature. So, in order to get to that data I added an >additional > > search form to search.phtml, and copied info.phtml and called a dbase >search > > using php to return records from the table with no shapefile ties. >After > > using this method for awhile and finding it slow, I've converted the dbf > > files to a postgres tables so that its easier to deal with them and I >can > > index them for MUCH better performance. > > > > This worked so well for me that I've extended this to do searches on a > > couple of mysql dbs as well. > > > > As to mapping, I'm very close to finding a quick way to create point >data >in > > a shape so that each of my featureless data records will now be able to >be > > mapped when I want them mapped. > > > > In order to do this you'll have to either write a new query class and a > > couple of new print functions, or alter the ones that Armin has >provided, >so > > that it will create a zoompoint link rather than zoomextent. Not >trivial > > but not too difficult either. Because I wasn't mapping these tables I >just > > encapsulated all of that functionality in my altered info_data.phtml. > > > > I do encourage you to setup Postgres with PostGIS if you are planning on > > doing much pure data manipulation. The windows installer for Postgres >and > > PostGIS are very simple to use and you'll find that you gain lots of > > advantages over using shape files and dbf files. > > > > Good luck! > > -- > > Things are only difficult while you don't understand them. > > > > > > > > > >> From: "toni" <fiorenontaglio at libero.it> > >> To: "pmapper mailing list" <pmapper-users at faunalia.it> > >> Subject: [Pmapper-users] attribute query and records with no geometry > >> Date: Tue, 23 May 2006 23:23:05 +0200 > >> > >> Hi everybody, > >> > >> i'm using win xp, ms4w v.1.5.0, pmapper 1.2.0, shape files for layers. > >> > >> I've set as pmapper layer a shape file including records without >geometry > >> (let me explain: my shape .dbf file contains records not linked with >the > >> objects in the .shp file, these records do not have geographic > >> localization). > >> If I use the attribute query in the search frame looking for a record > >> without geometry I get: "no data found", when instead data are stored. > >> > >> Does the attribute query work only if the geometry exists or not? > >> I created a "conventional geometry" for these records just to make the > >> query > >> work, but it doesn't seem the most correct way to avoid the problem >(bigger > >> file for nothing, slow map loading) > >> > >> thanks > >> toni > >> > >> > >> > >> _______________________________________________ > >> Pmapper-users mailing list > >> Pmapper-users at faunalia.it > >> http://faunalia.it/cgi-bin/mailman/listinfo/pmapper-users > > > > > > > > _______________________________________________ > > Pmapper-users mailing list > > Pmapper-users at faunalia.it > > http://faunalia.it/cgi-bin/mailman/listinfo/pmapper-users > > > > > > >_______________________________________________ >Pmapper-users mailing list >Pmapper-users at faunalia.it >http://faunalia.it/cgi-bin/mailman/listinfo/pmapper-users
