[Qgis-user] Convert huge shapefile to small size

[Madry, Scott]

Thanks Chris, but I do think that this is a topic is worth considering by the QGIS community, beyond the limitations of the archaeic shapefile format. We are moving into an era of very big data, both raster and vector, and QGIS should be able to meet this challenge. This will require some foresight and planning, thus my raising the issue. Or not...

Best,

Scott

On Jul 28, 2022, at 4:05 PM, chris hermansen <clhermansen at gmail.com<mailto:clhermansen at gmail.com>> wrote:

Scott and list,

With respect I think this conversation is moving off the point, which was related to a 5gb shapefile

https://en.m.wikipedia.org/wiki/Shapefile

Which is beyond the design limits of the Shapefile standards and perhaps therefore the source of the problem that the OP has.

Notably not a limitation of QGIS

On Thu, Jul 28, 2022, 10:45 Madry, Scott via Qgis-user <qgis-user at lists.osgeo.org<mailto:qgis-user at lists.osgeo.org>> wrote:
Dear colleagues,

As we move more into the world of big data, IOE, data mining, and data analytics, dealing with larger and larger data sets will become required, and, eventually, the norm.

GRASS GIS has made very good progress in this regard, optimizing the code to run on massively parallel computer architectures, with very good effect:

https://grasswiki.osgeo.org/wiki/Supercomputing

Perhaps it is time for QGIS to consider this in its future development plans? We will certainly be needing this in the future.

And thanks to all the team who keep the QGIS train running, I am constantly amazed at the energy, effort, and availability of people to the broader community.

Scott

Scott Madry, Ph.D.
Research Associate Professor of Archaeology
The University of North Carolina at Chapel Hill

Tel         1-919-448-4493
Email:    madrys at email.unc.edu<mailto:madrys at email.unc.edu>
https://scottmadry.web.unc.edu<https://scottmadry.web.unc.edu/>
Skype:   scott madry



On Jul 28, 2022, at 10:14 AM, jhubbslist--- via Qgis-user <qgis-user at lists.osgeo.org<mailto:qgis-user at lists.osgeo.org>> wrote:

Past a point, trying to run a GIS app with very large data structures just doesn't work well. If you really need all the information you're carrying around for your analysis or whatever, you may need to reach for different tools or use the tools you have differently.

I assume it's not so much the >5GiB of disk space that's the issue and that you've maxxed out the CPU, graphics, and disk I/O rate as much as is practical so mostly it's a matter of how long it takes maps etc. to paint onscreen. It may help you to move the heavy-lift onto PostgreSQL/PostGIS where you can make use of spatial indexing. Or, you can craft your operations the way you want them in QGIS but do the actual work with e.g. GDAL calls in Python. I spoke with someone a couple weeks ago whose particular GIS process worked better in GRASS than in QGIS, so that's something you might look into as well.

On 7/28/22 7:52 AM, krishna Ayyala via Qgis-user wrote:
dbf file itself is 5.1GB. Rest all other files are less than 500MB. It is the number of records which is huge. It has about 117,2100 points.

On Thu, Jul 28, 2022 at 12:02 AM Bernd Vogelgesang via Qgis-user <qgis-user at lists.osgeo.org<mailto:qgis-user at lists.osgeo.org>> wrote:
how big is the dbf file of that shape? Maybe you can also drop some
attributes.

Am 28.07.22 um 03:46 schrieb krishna Ayyala via Qgis-user:
> Hello,
> I have a shapefile of 5GB in size. Is it possible to convert this
> shapefile to a smaller size file? It can be any format, not
> necessarily a shapefile. But, preferably a vector format. I tried to
> convert it into tiles, but that didn't work as it was losing the
> resolution. I am looking to convert this 5GB size file to about 500MB.
>
> Regards.
>
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