[QGIS-Developer] How does QGIS parses the shapefile so quickly (? ??)

[Colin Sare-Soar]

I can't say why QGIS handles Shapefiles so quickly but I do have experience of reading and writing them for myself. 
I didn't want to use Shapelib - too big and cumbersome so I just added read/write functions to my application and used the ESRI document for reference. It is quite easy to follow but you have to be careful with the endian-ness of the different fields.
Just search for 'ESRI Shapefile format' and you should find their document.
> On 28/03/2023 02:00 +07 qgis-developer-request at lists.osgeo.org wrote:
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>    1. How does QGIS parses the shapefile so quickly (? ??)
>    2. Re: How does QGIS parses the shapefile so quickly
>       (Alessandro Pasotti)
>    3. Re: How does QGIS parses the shapefile so quickly (Even Rouault)
>    4. Re: How does QGIS parses the shapefile so quickly (Werner Macho)
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> Dear All,
>   Sorry to interrupt, I'm newer to QGIS, whe I use QIGS, I find that it is so quick for QGIS to parse shapefile even it is a very big file, I try to decode the file by my own with shapelib library, but the result is disappointed, I try to learn it by myself with QGIS source code but failed, so anyone can help point the entry of  decoding process?
> 
> Thanks.Hi,
> 
> QGIS is using the GDAL/OGR library to read the shapefiles.
> 
> On Mon, Mar 27, 2023 at 9:51 AM 余 绍健 via QGIS-Developer
> <qgis-developer at lists.osgeo.org> wrote:
> >
> > Dear All,
> >   Sorry to interrupt, I'm newer to QGIS, whe I use QIGS, I find that it is so quick for QGIS to parse shapefile even it is a very big file, I try to decode the file by my own with shapelib library, but the result is disappointed, I try to learn it by myself with QGIS source code but failed, so anyone can help point the entry of  decoding process?
> >
> > Thanks.
> > _______________________________________________
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> > QGIS-Developer at lists.osgeo.org
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> 
> 
> -- 
> Alessandro Pasotti
> QCooperative:  www.qcooperative.net
> ItOpen:   www.itopen.it
> 
> 
> Le 27/03/2023 à 10:06, Alessandro Pasotti via QGIS-Developer a écrit :
> > Hi,
> >
> > QGIS is using the GDAL/OGR library to read the shapefiles.
> which uses shapelib
> >
> > On Mon, Mar 27, 2023 at 9:51 AM 余 绍健 via QGIS-Developer
> > <qgis-developer at lists.osgeo.org> wrote:
> >> Dear All,
> >>    Sorry to interrupt, I'm newer to QGIS, whe I use QIGS, I find that it is so quick for QGIS to parse shapefile even it is a very big file, I try to decode the file by my own with shapelib library, but the result is disappointed, I try to learn it by myself with QGIS source code but failed, so anyone can help point the entry of  decoding process?
> >>
> >> Thanks.
> >> _______________________________________________
> >> QGIS-Developer mailing list
> >> QGIS-Developer at lists.osgeo.org
> >> List info: https://lists.osgeo.org/mailman/listinfo/qgis-developer
> >> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-developer
> >
> >
> -- 
> http://www.spatialys.com
> My software is free, but my time generally not.
> 
> 
> Hi!
> Just to add some side information regarding Shapefiles:
> (ignore it if understanding shapefiles ist a must in your case)
> 
> http://switchfromshapefile.org/
> 
> ;)
> regards
> Werner
> 
> On Mon, Mar 27, 2023 at 5:16 PM Even Rouault via QGIS-Developer <qgis-developer at lists.osgeo.org> wrote:
> > Le 27/03/2023 à 10:06, Alessandro Pasotti via QGIS-Developer a écrit :
> > > Hi,
> > >
> > > QGIS is using the GDAL/OGR library to read the shapefiles.
> > which uses shapelib
> > >
> > > On Mon, Mar 27, 2023 at 9:51 AM 余 绍健 via QGIS-Developer
> > > <qgis-developer at lists.osgeo.org> wrote:
> > >> Dear All,
> > >>    Sorry to interrupt, I'm newer to QGIS, whe I use QIGS, I find that it is so quick for QGIS to parse shapefile even it is a very big file, I try to decode the file by my own with shapelib library, but the result is disappointed, I try to learn it by myself with QGIS source code but failed, so anyone can help point the entry of  decoding process?
> > >>
> > >> Thanks.
> > >> _______________________________________________
> > >> QGIS-Developer mailing list
> > >> QGIS-Developer at lists.osgeo.org
> > >> List info: https://lists.osgeo.org/mailman/listinfo/qgis-developer
> > >> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-developer
> > >
> > >
> > --
> > http://www.spatialys.com
> > My software is free, but my time generally not.
> > 
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