[Qgis-user] Buffer by Attribute Issue
Hi Folks Have a table full of points that I want to buffer by a variable distance. The distance is an attribute in the input table in km. Using Vector>Geoprocessing>Buffer It works fine if I specify a fixed buffer. When I run it with the attribute selected it runs fine but it will not paint the buffers. At first I thought I had a unit issue so added an expression to multiply the attribute by 1000 to get to km from m as I wasn't sure if the default was m. The buffered output behaves totally normally so I can label, and zoom to features... All looks fine except no actual buffers draw. Symbology panel looks normal. Just wondering if anyone has seen this or knows of a workaround or thoughts on what I am doing wrong. I am running 3.16.8 Hannover on mac OS 11.6 thanks Peter ___ 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] Buffer by Attribute Issue
Hi, sorry, but can't reproduce your problem (but on Linux Mint QGIS 3.22). Generated 100 random points and added a field "buffer" from $id*10. Everything fine here. Bernd Am 15.12.21 um 16:26 schrieb Peter Devanney: Hi Folks Have a table full of points that I want to buffer by a variable distance. The distance is an attribute in the input table in km. Using Vector>Geoprocessing>Buffer It works fine if I specify a fixed buffer. When I run it with the attribute selected it runs fine but it will not paint the buffers. At first I thought I had a unit issue so added an expression to multiply the attribute by 1000 to get to km from m as I wasn't sure if the default was m. The buffered output behaves totally normally so I can label, and zoom to features... All looks fine except no actual buffers draw. Symbology panel looks normal. Just wondering if anyone has seen this or knows of a workaround or thoughts on what I am doing wrong. I am running 3.16.8 Hannover on mac OS 11.6 thanks Peter ___ 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] Buffer by Attribute Issue
Peter and list, On Wed, Dec 15, 2021 at 7:26 AM Peter Devanney wrote: > Hi Folks > > Have a table full of points that I want to buffer by a variable distance. > The distance is an attribute in the input table in km. > > Using Vector>Geoprocessing>Buffer It works fine if I specify a fixed > buffer. > > When I run it with the attribute selected it runs fine but it will not > paint the buffers. At first I thought I had a unit issue so added an > expression to multiply the attribute by 1000 to get to km from m as I > wasn't sure if the default was m. > > The buffered output behaves totally normally so I can label, and zoom to > features... All looks fine except no actual buffers draw. Symbology panel > looks normal. > > Just wondering if anyone has seen this or knows of a workaround or > thoughts on what I am doing wrong. > > What is the type of your buffer item? What are the typical values? What is your CRS? -- Chris Hermansen · clhermansen "at" gmail "dot" com C'est ma façon de parler. ___ 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] Buffer by Attribute Issue
Chris The buffer input is a point the lat and long are Doubles. The buffer distance variable is a Double. Using EPSG 3857 for all. Not sure what the protocol on the list is or if it will accept a small 2 MB .mp4 but I can show what I am doing for workflow if that might help? thanks Chris Peter On Wed, Dec 15, 2021 at 6:42 PM chris hermansen wrote: > Peter and list, > > On Wed, Dec 15, 2021 at 7:26 AM Peter Devanney wrote: > >> Hi Folks >> >> Have a table full of points that I want to buffer by a variable distance. >> The distance is an attribute in the input table in km. >> >> Using Vector>Geoprocessing>Buffer It works fine if I specify a fixed >> buffer. >> >> When I run it with the attribute selected it runs fine but it will not >> paint the buffers. At first I thought I had a unit issue so added an >> expression to multiply the attribute by 1000 to get to km from m as I >> wasn't sure if the default was m. >> >> The buffered output behaves totally normally so I can label, and zoom to >> features... All looks fine except no actual buffers draw. Symbology panel >> looks normal. >> >> Just wondering if anyone has seen this or knows of a workaround or >> thoughts on what I am doing wrong. >> >> What is the type of your buffer item? What are the typical values? > > What is your CRS? > > > -- > Chris Hermansen · clhermansen "at" gmail "dot" com > > C'est ma façon de parler. > ___ 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] Buffer by Attribute Issue
On 12/16/21 16:08, Peter Devanney wrote: Chris The buffer input is a point the lat and long are Doubles. The buffer distance variable is a Double. Using EPSG 3857 for all. So your data is in lat/lon so in degrees? Or in EPSG:3857 units (more or less meters)? Can you show the coordinates of your point layer (also EPSG:3857 ?) What if you select/copy one point, does it look like (a point in NL) wkt_geom Point (542953.32029126526322216 6792876.35233329329639673) or wkt_geom Point (5.50943334180317645 52.15814766031191851) ? Not sure what the protocol on the list is or if it will accept a small 2 MB .mp4 but I can show what I am doing for workflow if that might help? Nope, I think attachments > 75kB are removed or held back Regards, Richard ___ 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] Buffer by Attribute Issue
The list accepts, I think, 100kb, so you might want to dump your .mp4 somewhere else and post a link. EPSG 3857 is not the most clever CRS to work with, but that depends on your points locations and what you want to do with them. Am 16.12.21 um 16:08 schrieb Peter Devanney: Chris The buffer input is a point the lat and long are Doubles. The buffer distance variable is a Double. Using EPSG 3857 for all. Not sure what the protocol on the list is or if it will accept a small 2 MB .mp4 but I can show what I am doing for workflow if that might help? thanks Chris Peter On Wed, Dec 15, 2021 at 6:42 PM chris hermansen mailto:clherman...@gmail.com>> wrote: Peter and list, On Wed, Dec 15, 2021 at 7:26 AM Peter Devanney mailto:pe...@devanney.ca>> wrote: Hi Folks Have a table full of points that I want to buffer by a variable distance. The distance is an attribute in the input table in km. Using Vector>Geoprocessing>Buffer It works fine if I specify a fixed buffer. When I run it with the attribute selected it runs fine but it will not paint the buffers. At first I thought I had a unit issue so added an expression to multiply the attribute by 1000 to get to km from m as I wasn't sure if the default was m. The buffered output behaves totally normally so I can label, and zoom to features... All looks fine except no actual buffers draw. Symbology panel looks normal. Just wondering if anyone has seen this or knows of a workaround or thoughts on what I am doing wrong. What is the type of your buffer item? What are the typical values? What is your CRS? -- Chris Hermansen · clhermansen "at" gmail "dot" com C'est ma façon de parler. ___ 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] Buffer by Attribute Issue
Example point in the project CRS ( EPSG:3857) -11923424,5461258 I have had the buffer problem with a GCS like but just usually convert to a UTM to do analysis. I was using a pseudo mercator here because the web maps are in that CRS and don't distort as a base map for a quick view of some data. Buffer works with a fixed distance specified in the Buffer dialog; but not when I try to use an attribute from the table as a buffer distance variable. thanks Peter On Thu, Dec 16, 2021 at 10:19 AM Richard Duivenvoorde wrote: > On 12/16/21 16:08, Peter Devanney wrote: > > Chris > > > > The buffer input is a point the lat and long are Doubles. The buffer > distance variable is a Double. Using EPSG 3857 for all. > > So your data is in lat/lon so in degrees? > Or in EPSG:3857 units (more or less meters)? > Can you show the coordinates of your point layer (also EPSG:3857 ?) > > What if you select/copy one point, does it look like (a point in NL) > > wkt_geom > Point (542953.32029126526322216 6792876.35233329329639673) > > or > > wkt_geom > Point (5.50943334180317645 52.15814766031191851) > > ? > > > > Not sure what the protocol on the list is or if it will accept a small 2 > MB .mp4 but I can show what I am doing for workflow if that might help? > > Nope, I think attachments > 75kB are removed or held back > > Regards, > > Richard > ___ 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] Buffer by Attribute Issue
Peter and list On Thu, Dec 16, 2021 at 7:08 AM Peter Devanney wrote: > Chris > > The buffer input is a point the lat and long are Doubles. The buffer > distance variable is a Double. Using EPSG 3857 for all. > I just created a point shapefile in EPSG:3857, added a field called "bufferdist", added three points with bufferdist set to 1000, 2000 and 5000 respectively. EPSG:3857 is in metres, are readily visible and as far as I can tell from measuring the buffers were correctly created in the correct size. In the buffer dialogue did you click on the button next to the distance / units pair and next to "field type >" select your field, which would deactivate the distance / units pair? Your mention of "lat and long" troubles me. EPSG:3857 is a projected coordinate system, not a lat/lon system. > > Not sure what the protocol on the list is or if it will accept a small 2 > MB .mp4 but I can show what I am doing for workflow if that might help? > > thanks Chris > > Peter > > On Wed, Dec 15, 2021 at 6:42 PM chris hermansen > wrote: > >> Peter and list, >> >> On Wed, Dec 15, 2021 at 7:26 AM Peter Devanney wrote: >> >>> Hi Folks >>> >>> Have a table full of points that I want to buffer by a variable >>> distance. The distance is an attribute in the input table in km. >>> >>> Using Vector>Geoprocessing>Buffer It works fine if I specify a fixed >>> buffer. >>> >>> When I run it with the attribute selected it runs fine but it will not >>> paint the buffers. At first I thought I had a unit issue so added an >>> expression to multiply the attribute by 1000 to get to km from m as I >>> wasn't sure if the default was m. >>> >>> The buffered output behaves totally normally so I can label, and zoom to >>> features... All looks fine except no actual buffers draw. Symbology panel >>> looks normal. >>> >>> Just wondering if anyone has seen this or knows of a workaround or >>> thoughts on what I am doing wrong. >>> >>> What is the type of your buffer item? What are the typical values? >> >> What is your CRS? >> >> >> -- >> Chris Hermansen · clhermansen "at" gmail "dot" com >> >> C'est ma façon de parler. >> > -- Chris Hermansen · clhermansen "at" gmail "dot" com C'est ma façon de parler. ___ 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] Buffer by Attribute Issue
Chris and list It is working for me now. Sorry, when I said lat/long I had meant the points were imported as Lat/Long EPSG:4326 from a text file. But subsequently projected to 3857. Example point in the project CRS ( EPSG:3857) -11923424,5461258 So I think I found the problem. Seems one workflow works and the other doesn't. You must select the Attribute Field from the field list and then edit the expression. This works. I thought I had tried it yesterday but suspect I didn't have the expression right. What I spent time with was using the Assistant dialog. That did not work. I was able to reproduce that it does not work. So the workflow that works is select the attribute Field and then go to Edit the Expression. I was unable to get it working using the Assistant dialog. thanks for the great help! Peter On Thu, Dec 16, 2021 at 2:50 PM chris hermansen wrote: > Peter and list > > On Thu, Dec 16, 2021 at 7:08 AM Peter Devanney wrote: > >> Chris >> >> The buffer input is a point the lat and long are Doubles. The buffer >> distance variable is a Double. Using EPSG 3857 for all. >> > > I just created a point shapefile in EPSG:3857, added a field called > "bufferdist", added three points with bufferdist set to 1000, 2000 and 5000 > respectively. > > EPSG:3857 is in metres, are readily visible and as far as I can tell from > measuring the buffers were correctly created in the correct size. > > In the buffer dialogue did you click on the button next to the distance / > units pair and next to "field type >" select your field, which would > deactivate the distance / units pair? > > Your mention of "lat and long" troubles me. EPSG:3857 is a projected > coordinate system, not a lat/lon system. > >> >> Not sure what the protocol on the list is or if it will accept a small 2 >> MB .mp4 but I can show what I am doing for workflow if that might help? >> >> thanks Chris >> >> Peter >> >> On Wed, Dec 15, 2021 at 6:42 PM chris hermansen >> wrote: >> >>> Peter and list, >>> >>> On Wed, Dec 15, 2021 at 7:26 AM Peter Devanney >>> wrote: >>> Hi Folks Have a table full of points that I want to buffer by a variable distance. The distance is an attribute in the input table in km. Using Vector>Geoprocessing>Buffer It works fine if I specify a fixed buffer. When I run it with the attribute selected it runs fine but it will not paint the buffers. At first I thought I had a unit issue so added an expression to multiply the attribute by 1000 to get to km from m as I wasn't sure if the default was m. The buffered output behaves totally normally so I can label, and zoom to features... All looks fine except no actual buffers draw. Symbology panel looks normal. Just wondering if anyone has seen this or knows of a workaround or thoughts on what I am doing wrong. What is the type of your buffer item? What are the typical values? >>> >>> What is your CRS? >>> >>> >>> -- >>> Chris Hermansen · clhermansen "at" gmail "dot" com >>> >>> C'est ma façon de parler. >>> >> > > -- > Chris Hermansen · clhermansen "at" gmail "dot" com > > C'est ma façon de parler. > ___ 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
