Re: [Qgis-user] Symbology

2022-06-17 Thread Kobben, Barend (UT-ITC) via Qgis-user 
Usually this happens if you have numbers (quantitatvie data) that are stored in 
your file/db as Strings (text)

--
Barend Köbben


On 18/06/2022, 04:25, "Qgis-user on behalf of chris hermansen via Qgis-user" 
mailto:qgis-user-boun...@lists.osgeo.org> on 
behalf of Qgis-user@lists.osgeo.org> wrote:

Allan and list,

On Fri, Jun 17, 2022 at 7:00 PM Allan Younger via Qgis-user 
mailto:qgis-user@lists.osgeo.org>> wrote:
Hi,
I'm trying to show assay results as simple dot plots as graduated colour and 
size scaled points based on a selected element.
Problem is that in the layer properties/symbology tab, I cannot select anything.
Had the problem in Madeira 3.4 & assumed was just a glitch that had developed 
in that copy over time.
Installed 3.22.7, same problem.
Csv file has 162000 records & 30 column with co-ords for every point; with 
locations plotting a-ok.

At the top of the Layer Properties > Symbology dialogue window, have you 
selected one of the options other than "No Symbols"?  For example, "Graduated"?

Then in the field Value one of your layer's attributes?

Then pressed the "Classify" button?

--
Chris Hermansen · clhermansen "at" gmail "dot" com

C'est ma façon de parler.
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Re: [Qgis-user] Symbology

2022-06-17 Thread chris hermansen via Qgis-user 
Allan and list,

On Fri, Jun 17, 2022 at 7:00 PM Allan Younger via Qgis-user <
qgis-user@lists.osgeo.org> wrote:

> Hi,
> I'm trying to show assay results as simple dot plots as graduated colour
> and size scaled points based on a selected element.
> Problem is that in the layer properties/symbology tab, I cannot select
> anything.
> Had the problem in Madeira 3.4 & assumed was just a glitch that had
> developed in that copy over time.
> Installed 3.22.7, same problem.
> Csv file has 162000 records & 30 column with co-ords for every point; with
> locations plotting a-ok.
>
> At the top of the Layer Properties > Symbology dialogue window, have you
selected one of the options other than "No Symbols"?  For example,
"Graduated"?

Then in the field Value one of your layer's attributes?

Then pressed the "Classify" button?

-- 
Chris Hermansen · clhermansen "at" gmail "dot" com

C'est ma façon de parler.
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[Qgis-user] Symbology

2022-06-17 Thread Allan Younger via Qgis-user 

Hi,
I'm trying to show assay results as simple dot plots as graduated colour 
and size scaled points based on a selected element.
Problem is that in the layer properties/symbology tab, I cannot select 
anything.
Had the problem in Madeira 3.4 & assumed was just a glitch that had 
developed in that copy over time.

Installed 3.22.7, same problem.
Csv file has 162000 records & 30 column with co-ords for every point; 
with locations plotting a-ok.

Cheers
Allan Younger

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Re: [Qgis-user] most efficient way to digitize polygons

2022-06-17 Thread Alexandre Neto via Qgis-user 
Hello Byron,

There are a couple of solutions I normally use in those situations.

But before that take a look at the snapping documentation:

https://docs.qgis.org/3.22/en/docs/user_manual/working_with_vector/editing_geometry_attributes.html#topological-editing

Also check the digitising on the layer properties to constantly validation:

https://docs.qgis.org/3.22/en/docs/user_manual/working_with_vector/vector_properties.html#digitizingmenu

Other than that, I normally prefer to create one by polygon and then split
it with the split geometries tool, but make sure to enable topological
editing.


The other option is using the avoid overlapping option, that way you can do
just a few click in the inside an neighbours polygons and qgis will draw
the boundary for yoy.

Third option, use the tracing tool.

Best regards,

Alexandre Neto
Users support
www.qcooperative.net



A quinta, 16/06/2022, 17:43, Nicolas Cadieux via Qgis-user <
qgis-user@lists.osgeo.org> escreveu:

> Hi,
>
> Depending on what you are doing and what kind of results you are looking
> for, could you simply use "Polygonize" and then clean those results.  If
> your map are in RGB only, you could do a raster classification analysis
> before hand.  Line would follow pixels at first but those could be fixed
> using various vector tools.
>
> Just a thought!
>
> Nicolas
> On 2022-06-16 11:26 a.m., Firstname Lastname via Qgis-user wrote:
>
> i am a qgis newby and i am beginning a large project that involves
> digitizing several geology maps.  i am trying to determine the best way to
> manage the digitizing and avoid extra work.
> my question to the group is:  If i have several coloured polygons that are
> adjacent to each other, is there an efficient way to digitize one polygon
> and then use one edge of that polygon for the adjacent polygon so that i
> dont have to redigitize the same edge twice and so that i will have
> precisely overrlapping polys with no gaps?  should i digitize one polygon,
> export and rename it?  can i digitize one have of the next polygon and
> somehow merge it with the now re-imported polygon?
> is there a more efficient way to do this?
>
> many thanks
>
> --
> Byron Veilleux, MSc. P.Geo
> Conjugate Geologic Services Limited
> Calgary, Alberta Canada
> by...@conjugategeo.com
>
>
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> Nicolas Cadieuxhttps://gitlab.com/njacadieux
>
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Re: [Qgis-user] digitizing

2022-06-17 Thread Patrick Dunford via Qgis-user 
There are some times when the libraries can run out of memory if a 
raster is very large, so you can have something that something like a 
graphics editor e.g Gimp can open OK but Qgis coujld have trouble 
opening it.


On 17/06/22 14:22, Firstname Lastname wrote:
I think that there is something wrong with the Tif file I was using.  
I had the same problem with a couple of files but I went back to the 
source file and redid the referencing and it is ok.


On Thu, Jun 16, 2022 at 7:46 PM Patrick Dunford via Qgis-user 
 wrote:


This is a generic answer, as more information would be needed to
determine exactly the situation you are experiencing.

If you zoom to the layer, is it then displayed in the same place
as the rest of your map?

My recollection of the georeferencer is it produces a world file
to go with the layer. This should have the correct top-left
coordinates and pixel resolution in it. Is there also an XML file
that specifies the CRS?

Look at the layer name where it is loaded in the GIS and see if
there is a question mark displayed next to its name, that
indicates QGIS doesn't have enough information to position the
layer, such as the information that is stored in sidecar files.

It is also possible if the file is very large that it will be slow
to display. Also have a look at the error log at the bottom of the
screen to see if any error messages are displayed.

On 17/06/22 04:23, Firstname Lastname via Qgis-user wrote:

i have been successfully using the georeferencer for some time. 
i referenced several maps and they succesfully georeferenced
and  displayed for me.
Then, i was digitizing and i ran the georeference tool and for
some reason, the new referenced maps do not display.  i have
exited and tried to georef in a new project and made sure that i
have the same CRS for the basemap and the georef tool but when i
run the referencer, the layer appear but the map will not
display.  i have tried restarting, clearing the georef tool and
running again but i get the same result.   Does anyone know what
i am doing wrong and why my referenced maps will not display?

-- 
Byron Veilleux, MSc. P.Geo

Conjugate Geologic Services Limited
Calgary, Alberta Canada
by...@conjugategeo.com
Cell:4037108414

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--
Byron Veilleux, MSc. P.Geo
Conjugate Geologic Services Limited
Calgary, Alberta Canada
by...@conjugategeo.com
Cell:4037108414___
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