Re: [Qgis-user] Join multiple Linestrings to single Linestring
Hi, just to clarify things (all info is AFAIK): 1) Processing: a) processing always creates a new layer as output b) Dissolve always creates multi features c) running multi-to-single afterwards creates single features for any connecting parts d) b) and c) can be put into a model to run them in one step e) Depending on its settings processing processes either the selected or all features of the input layer 2) Digitising: a) works within the current layer and manipulates certain features b) "merge selected features" creates single features if the lines are connected (= endpoints are snapped) and the geometry column is defined as Linestring in PostGIS (just tested with QGIS 2.14.13); may behave differently for other data providers c) "merge selected features" deletes all existing datasets and inserts a new one; if you want to keep an existing dataset (foreign keys!) use DigitizingTools plugin's "merge selected features" instead Bernhard Am 20.04.2017 um 08:40 schrieb fuenfer-koenigstein.benja...@swm.de: Hi Richard, thanks again for your reply! I’m really amazed about the active community around QGIS, never experienced that with any other GIS-Software! ‘Merge Selected Features’ is exactly the tool that I initially wanted to use and then realized that it creates multiline-features which causes problems with my linestring db table. Meanwhile I will use QAD plugin that creates linestring or I will work with a local copy as you suggested. So for me it works quite OK with this workaround, but maybe it would be helpful to have an option to choose between creating multilinestring or linestring when using the ‘Merge’ tool. What do others think? Useful and important enough to open an issue? Regards Benni *Von:*Richard McDonnell [mailto:richard.mcdonn...@opw.ie] *Gesendet:* Mittwoch, 19. April 2017 16:02 *An:* Fuenfer-Koenigstein.Benjamin G-PRA; qgis-user@lists.osgeo.org *Betreff:* Re: AW: [Qgis-user] Join multiple Linestrings to single Linestring Another option, you could try is using the*Advanced Digitising Toolbar* under *View, Toolbars *Select the lines you want to merge/Join and click *Merge Selected Features*. This should also allow you to edit the DB directly from QGIS. I have not tried it, so your issue with Multi-Lines instead of single linestrings may still apply. You could still use the above example on the locally saved version of the table though and upload and overwrite the changed dataset. Sorry I cant be of more help. Reagrds, Richard. On 19/04/2017 14:07, fuenfer-koenigstein.benja...@swm.de <mailto:fuenfer-koenigstein.benja...@swm.de> wrote: Hi Richard, thanks for your suggestion! I think Dissolve won’t work for me as it’s applied to the whole layer (hope I understood this right). I’m looking for a way to easily merge certain linestrings when I, for example, want to create one geometry by first creating a spline and then a straight line feature. I will try out your workaround with local files. But as the db-source is very large (> 500.000 rows) I’m happy for any other suggestion to solve it directly in QGIS with db-source. Regards Benjamin *Von:*Richard McDonnell [mailto:richard.mcdonn...@opw.ie] *Gesendet:* Mittwoch, 19. April 2017 10:10 *An:* David J. Bakeman; Fuenfer-Koenigstein.Benjamin G-PRA; qgis-user@lists.osgeo.org <mailto:qgis-user@lists.osgeo.org> *Betreff:* Re: [Qgis-user] Join multiple Linestrings to single Linestring Benjamin, You could try Dissolve, under Geoprocessing Tools, alternatively you could try saving the dataset locally as a shapefile, edit using either of the methods you outlined below, In relation to saving the edits back to the table as linestring, use the DB Manager tool, select the table you wish to update, tick the options you want, making sure both *Replace destination Table (if exists) *and*Create single-part geometries instead of multi-part* This has worked for me in the past, admittedly for polygons, but it should also work for linestrings. Hope this helps, Richard. On 18/04/2017 17:24, David J. Bakeman wrote: On 04/18/2017 02:17 AM, fuenfer-koenigstein.benja...@swm.de <mailto:fuenfer-koenigstein.benja...@swm.de> wrote: Hi there, I want to merge multiple linestrings with same start/endpoint to a single linestring (all lines within one layer). As I use a PostGIS source with geometry type linestring, it is important that the new geometry is still linestring and not multilinestring type. "Merge selected features" tool and "JOIN" in QAD-Plugin both create multilinestrings. Has anyone an idea how to directly merge into linestring or how to change geometry type after merging? Thanks for your suggestions! I'm not sure I completely understand what you want but you could ru
Re: [Qgis-user] Join multiple Linestrings to single Linestring
Hi Richard, thanks again for your reply! I’m really amazed about the active community around QGIS, never experienced that with any other GIS-Software! ‘Merge Selected Features’ is exactly the tool that I initially wanted to use and then realized that it creates multiline-features which causes problems with my linestring db table. Meanwhile I will use QAD plugin that creates linestring or I will work with a local copy as you suggested. So for me it works quite OK with this workaround, but maybe it would be helpful to have an option to choose between creating multilinestring or linestring when using the ‘Merge’ tool. What do others think? Useful and important enough to open an issue? Regards Benni Von: Richard McDonnell [mailto:richard.mcdonn...@opw.ie] Gesendet: Mittwoch, 19. April 2017 16:02 An: Fuenfer-Koenigstein.Benjamin G-PRA; qgis-user@lists.osgeo.org Betreff: Re: AW: [Qgis-user] Join multiple Linestrings to single Linestring Another option, you could try is using the Advanced Digitising Toolbar under View, Toolbars Select the lines you want to merge/Join and click Merge Selected Features. This should also allow you to edit the DB directly from QGIS. I have not tried it, so your issue with Multi-Lines instead of single linestrings may still apply. You could still use the above example on the locally saved version of the table though and upload and overwrite the changed dataset. Sorry I cant be of more help. Reagrds, Richard. On 19/04/2017 14:07, fuenfer-koenigstein.benja...@swm.de<mailto:fuenfer-koenigstein.benja...@swm.de> wrote: Hi Richard, thanks for your suggestion! I think Dissolve won’t work for me as it’s applied to the whole layer (hope I understood this right). I’m looking for a way to easily merge certain linestrings when I, for example, want to create one geometry by first creating a spline and then a straight line feature. I will try out your workaround with local files. But as the db-source is very large (> 500.000 rows) I’m happy for any other suggestion to solve it directly in QGIS with db-source. Regards Benjamin Von: Richard McDonnell [mailto:richard.mcdonn...@opw.ie] Gesendet: Mittwoch, 19. April 2017 10:10 An: David J. Bakeman; Fuenfer-Koenigstein.Benjamin G-PRA; qgis-user@lists.osgeo.org<mailto:qgis-user@lists.osgeo.org> Betreff: Re: [Qgis-user] Join multiple Linestrings to single Linestring Benjamin, You could try Dissolve, under Geoprocessing Tools, alternatively you could try saving the dataset locally as a shapefile, edit using either of the methods you outlined below, In relation to saving the edits back to the table as linestring, use the DB Manager tool, select the table you wish to update, tick the options you want, making sure both Replace destination Table (if exists) and Create single-part geometries instead of multi-part This has worked for me in the past, admittedly for polygons, but it should also work for linestrings. Hope this helps, Richard. On 18/04/2017 17:24, David J. Bakeman wrote: On 04/18/2017 02:17 AM, fuenfer-koenigstein.benja...@swm.de<mailto:fuenfer-koenigstein.benja...@swm.de> wrote: Hi there, I want to merge multiple linestrings with same start/endpoint to a single linestring (all lines within one layer). As I use a PostGIS source with geometry type linestring, it is important that the new geometry is still linestring and not multilinestring type. "Merge selected features" tool and "JOIN" in QAD-Plugin both create multilinestrings. Has anyone an idea how to directly merge into linestring or how to change geometry type after merging? Thanks for your suggestions! I'm not sure I completely understand what you want but you could run multipart to singleparts from the Vector/Geometry Tools menu on the multilinestring layer to generate a layer with just linestrings. Best regards Benjamin ___ Qgis-user mailing list Qgis-user@lists.osgeo.org<mailto: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<mailto:Qgis-user@lists.osgeo.org> List info: https://lists.osgeo.org/mailman/listinfo/qgis-user Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user -- Richard McDonnell GIS Specialist PgD GIS AssocSCSI OPW FRM Data Management 52 Stephens Green, Dublin 2. TEL: 01 6476543 [Das Bild wurde vom Absender entfernt.]<http://www.opw.ie/> -- Richard McDonnell GIS Specialist PgD GIS AssocSCSI OPW FRM Data Management 52 Stephens Green, Dublin 2. TEL: 01 6476543 [Das Bild wurde vom Absender entfernt.]<http://www.opw.ie/> ___ 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] Join multiple Linestrings to single Linestring
Another option, you could try is using the*Advanced Digitising Toolbar* under *View, Toolbars *Select the lines you want to merge/Join and click *Merge Selected Features*. This should also allow you to edit the DB directly from QGIS. I have not tried it, so your issue with Multi-Lines instead of single linestrings may still apply. You could still use the above example on the locally saved version of the table though and upload and overwrite the changed dataset. Sorry I cant be of more help. Reagrds, Richard. On 19/04/2017 14:07, fuenfer-koenigstein.benja...@swm.de wrote: Hi Richard, thanks for your suggestion! I think Dissolve won’t work for me as it’s applied to the whole layer (hope I understood this right). I’m looking for a way to easily merge certain linestrings when I, for example, want to create one geometry by first creating a spline and then a straight line feature. I will try out your workaround with local files. But as the db-source is very large (> 500.000 rows) I’m happy for any other suggestion to solve it directly in QGIS with db-source. Regards Benjamin *Von:*Richard McDonnell [mailto:richard.mcdonn...@opw.ie] *Gesendet:* Mittwoch, 19. April 2017 10:10 *An:* David J. Bakeman; Fuenfer-Koenigstein.Benjamin G-PRA; qgis-user@lists.osgeo.org *Betreff:* Re: [Qgis-user] Join multiple Linestrings to single Linestring Benjamin, You could try Dissolve, under Geoprocessing Tools, alternatively you could try saving the dataset locally as a shapefile, edit using either of the methods you outlined below, In relation to saving the edits back to the table as linestring, use the DB Manager tool, select the table you wish to update, tick the options you want, making sure both *Replace destination Table (if exists) *and*Create single-part geometries instead of multi-part* This has worked for me in the past, admittedly for polygons, but it should also work for linestrings. Hope this helps, Richard. On 18/04/2017 17:24, David J. Bakeman wrote: On 04/18/2017 02:17 AM,fuenfer-koenigstein.benja...@swm.de <mailto:fuenfer-koenigstein.benja...@swm.de> wrote: Hi there, I want to merge multiple linestrings with same start/endpoint to a single linestring (all lines within one layer). As I use a PostGIS source with geometry type linestring, it is important that the new geometry is still linestring and not multilinestring type. "Merge selected features" tool and "JOIN" in QAD-Plugin both create multilinestrings. Has anyone an idea how to directly merge into linestring or how to change geometry type after merging? Thanks for your suggestions! I'm not sure I completely understand what you want but you could run multipart to singleparts from the Vector/Geometry Tools menu on the multilinestring layer to generate a layer with just linestrings. Best regards Benjamin ___ Qgis-user mailing list Qgis-user@lists.osgeo.org <mailto: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 <mailto:Qgis-user@lists.osgeo.org> List info:https://lists.osgeo.org/mailman/listinfo/qgis-user Unsubscribe:https://lists.osgeo.org/mailman/listinfo/qgis-user -- *_Richard McDonnell_* *GIS Specialist PgD GIS AssocSCSI* *OPW FRM Data Management* *52 Stephens Green, Dublin 2.* TEL: 01 6476543 Das Bild wurde vom Absender entfernt. <http://www.opw.ie/> -- *_Richard McDonnell_* *GIS Specialist PgD GIS AssocSCSI* *OPW FRM Data Management* *52 Stephens Green, Dublin 2.* TEL: 01 6476543 OPW - Ag féachaint don am atá le teacht - Ag caomhnú ón am atá thart OPW - Looking to the future - Caring for the past *** Email Disclaimer: http://www.opw.ie/en/disclaimer/ ___ 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] Join multiple Linestrings to single Linestring
Benjamin, You could try Dissolve, under Geoprocessing Tools, alternatively you could try saving the dataset locally as a shapefile, edit using either of the methods you outlined below, In relation to saving the edits back to the table as linestring, use the DB Manager tool, select the table you wish to update, tick the options you want, making sure both *Replace destination Table (if exists) *and*Create single-part geometries instead of multi-part* This has worked for me in the past, admittedly for polygons, but it should also work for linestrings. Hope this helps, Richard. On 18/04/2017 17:24, David J. Bakeman wrote: On 04/18/2017 02:17 AM, fuenfer-koenigstein.benja...@swm.de wrote: Hi there, I want to merge multiple linestrings with same start/endpoint to a single linestring (all lines within one layer). As I use a PostGIS source with geometry type linestring, it is important that the new geometry is still linestring and not multilinestring type. "Merge selected features" tool and "JOIN" in QAD-Plugin both create multilinestrings. Has anyone an idea how to directly merge into linestring or how to change geometry type after merging? Thanks for your suggestions! I'm not sure I completely understand what you want but you could run multipart to singleparts from the Vector/Geometry Tools menu on the multilinestring layer to generate a layer with just linestrings. Best regards Benjamin ___ 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 -- *_Richard McDonnell_* *GIS Specialist PgD GIS AssocSCSI* *OPW FRM Data Management* *52 Stephens Green, Dublin 2.* TEL: 01 6476543 OPW - Ag féachaint don am atá le teacht - Ag caomhnú ón am atá thart OPW - Looking to the future - Caring for the past *** Email Disclaimer: http://www.opw.ie/en/disclaimer/ ___ 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] Join multiple Linestrings to single Linestring
On 04/18/2017 02:17 AM, fuenfer-koenigstein.benja...@swm.de wrote: > Hi there, > > I want to merge multiple linestrings with same start/endpoint to a single > linestring (all lines within one layer). As I use a PostGIS source with > geometry type linestring, it is important that the new geometry is still > linestring and not multilinestring type. "Merge selected features" tool and > "JOIN" in QAD-Plugin both create multilinestrings. Has anyone an idea how to > directly merge into linestring or how to change geometry type after merging? > Thanks for your suggestions! I'm not sure I completely understand what you want but you could run multipart to singleparts from the Vector/Geometry Tools menu on the multilinestring layer to generate a layer with just linestrings. > > Best regards > > Benjamin > ___ > 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] Join multiple Linestrings to single Linestring
Hi there, I want to merge multiple linestrings with same start/endpoint to a single linestring (all lines within one layer). As I use a PostGIS source with geometry type linestring, it is important that the new geometry is still linestring and not multilinestring type. "Merge selected features" tool and "JOIN" in QAD-Plugin both create multilinestrings. Has anyone an idea how to directly merge into linestring or how to change geometry type after merging? Thanks for your suggestions! Best regards Benjamin ___ 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
