Re: [Qgis-user] Write vector attribute table from pandas dataframe
Thanks, Wouter and Nicolas I will give it a try. Cheers Ming On Sun, Apr 24, 2022 at 9:33 AM Wouter Impens via Qgis-user < qgis-user@lists.osgeo.org> wrote: > Hi, > > If you have a field to join on, you could export the dataframe to > something that is readable in QGIS like csv or xlsx > > Greetings > Wouter > > Op za 23 apr. 2022 om 19:34 schreef Nicolas Cadieux via Qgis-user < > qgis-user@lists.osgeo.org>: > >> Hi Ming, >> >> The best thing would be to show your code and ask others how it can be >> optimized. I find that https://gis.stackexchange.com/ is the best place >> to do this but this user list definitely has some very competent >> programmers. Not being one of those competent programmers, I will just >> state that pandas and geopandas use a process called vectorization where >> the “for loop” is done for you. >> >> >> https://medium.com/analytics-vidhya/understanding-vectorization-in-numpy-and-pandas-188b6ebc5398 >> >> This means that looping over elements in a dataframe can be MUCH slower >> than using vectorization. So basically, you need to figure out the right >> code and avoid “for loops“ when using dataframes. >> >> Hope this helps >> >> Nicolas Cadieux >> https://gitlab.com/njacadieux >> >> Le 22 avr. 2022 à 11:50, ming han via Qgis-user < >> qgis-user@lists.osgeo.org> a écrit : >> >> >> Hi everyone >> >> Is there an efficient way to copy data in a pandas dataframe to the >> vector attribute table? >> >> I am looping element by element, which is very slow. >> >> Thanks >> Ming >> ___ >> Qgis-user mailing list >> Qgis-user@lists.osgeo.org >> List info: https://lists.osgeo.org/mailman/listinfo/qgis-user >> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user >> >> ___ >> Qgis-user mailing list >> Qgis-user@lists.osgeo.org >> List info: https://lists.osgeo.org/mailman/listinfo/qgis-user >> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user >> > ___ > Qgis-user mailing list > Qgis-user@lists.osgeo.org > List info: https://lists.osgeo.org/mailman/listinfo/qgis-user > Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user > ___ Qgis-user mailing list Qgis-user@lists.osgeo.org List info: https://lists.osgeo.org/mailman/listinfo/qgis-user Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
Re: [Qgis-user] Write vector attribute table from pandas dataframe
Hi, If you have a field to join on, you could export the dataframe to something that is readable in QGIS like csv or xlsx Greetings Wouter Op za 23 apr. 2022 om 19:34 schreef Nicolas Cadieux via Qgis-user < qgis-user@lists.osgeo.org>: > Hi Ming, > > The best thing would be to show your code and ask others how it can be > optimized. I find that https://gis.stackexchange.com/ is the best place > to do this but this user list definitely has some very competent > programmers. Not being one of those competent programmers, I will just > state that pandas and geopandas use a process called vectorization where > the “for loop” is done for you. > > > https://medium.com/analytics-vidhya/understanding-vectorization-in-numpy-and-pandas-188b6ebc5398 > > This means that looping over elements in a dataframe can be MUCH slower > than using vectorization. So basically, you need to figure out the right > code and avoid “for loops“ when using dataframes. > > Hope this helps > > Nicolas Cadieux > https://gitlab.com/njacadieux > > Le 22 avr. 2022 à 11:50, ming han via Qgis-user > a écrit : > > > Hi everyone > > Is there an efficient way to copy data in a pandas dataframe to the > vector attribute table? > > I am looping element by element, which is very slow. > > Thanks > Ming > ___ > Qgis-user mailing list > Qgis-user@lists.osgeo.org > List info: https://lists.osgeo.org/mailman/listinfo/qgis-user > Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user > > ___ > Qgis-user mailing list > Qgis-user@lists.osgeo.org > List info: https://lists.osgeo.org/mailman/listinfo/qgis-user > Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user > ___ Qgis-user mailing list Qgis-user@lists.osgeo.org List info: https://lists.osgeo.org/mailman/listinfo/qgis-user Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
Re: [Qgis-user] Write vector attribute table from pandas dataframe
Hi Ming, The best thing would be to show your code and ask others how it can be optimized. I find that https://gis.stackexchange.com/ is the best place to do this but this user list definitely has some very competent programmers. Not being one of those competent programmers, I will just state that pandas and geopandas use a process called vectorization where the “for loop” is done for you. https://medium.com/analytics-vidhya/understanding-vectorization-in-numpy-and-pandas-188b6ebc5398 This means that looping over elements in a dataframe can be MUCH slower than using vectorization. So basically, you need to figure out the right code and avoid “for loops“ when using dataframes. Hope this helps Nicolas Cadieux https://gitlab.com/njacadieux > Le 22 avr. 2022 à 11:50, ming han via Qgis-user a > écrit : > > > Hi everyone > > Is there an efficient way to copy data in a pandas dataframe to the > vector attribute table? > > I am looping element by element, which is very slow. > > Thanks > Ming > ___ > Qgis-user mailing list > Qgis-user@lists.osgeo.org > List info: https://lists.osgeo.org/mailman/listinfo/qgis-user > Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user ___ Qgis-user mailing list Qgis-user@lists.osgeo.org List info: https://lists.osgeo.org/mailman/listinfo/qgis-user Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
