Feature request #4450: Legend symbols (in print composer) are ignoring the "scale size field" option in vector symbology - QGIS Application - QGIS Issue Tracking

Feature request #4450

Legend symbols (in print composer) are ignoring the "scale size field" option in vector symbology

Added by Giovanni Manghi over 12 years ago. Updated almost 7 years ago.

Status:	Open
Priority:	Normal
Assignee:	Vincent Mora
Category:	Map Composer/Printing
Pull Request or Patch supplied:	No	Resolution:
Easy fix?:	No	Copied to github as #:	14380

Description

As result all the symbols do show of the same size.

proportional_symbols.png (69.6 KB) julie -, 2011-11-02 02:06 AM

History

#1 Updated by Marco Hugentobler over 12 years ago

Not sure what you mean.
If the size comes from a field, the symbol size will be different for every feature. How should the legend handle this other than showing the symbol in a standard size?

#2 Updated by Giovanni Manghi over 12 years ago

Marco Hugentobler wrote:

Not sure what you mean.
If the size comes from a field, the symbol size will be different for every feature. How should the legend handle this other than showing the symbol in a standard size?

Example:

take a layer of cities (points), and make them represented with the categorized renderer (for example using the city region to classify with different colors) and then have them with different sizes using "scale size field", using for example the city population.

I would expect to have the different sizes represented in the legend of the print composer, but this doesn't work.

On the other end if you just uses the categorized renderer, without using the "scale size field", but then you manually change the size of the symbols manually, then in the print composer the legend works as expected -> a different symbol size for every feature.

I guess that if it works manually, it should work also with the "scale size field", also because sometimes the classes/features are just too many...

#3 Updated by Marco Hugentobler over 12 years ago

Tracker changed from Bug report to Feature request

I would expect to have the different sizes represented in the legend of the print composer, but this doesn't work.

Hm, but if you have 3000 cities with different sizes, you get 3000 symbols in the legend. I guess this option would mainly be useful in case of few objects in c composer map
Changing the ticket type to 'feature'.

#4 Updated by julie - over 12 years ago

File proportional_symbols.png added

Hi,
The idea is to get only a few example of symbols with different sizes in the legend. You usually get three, but being able to set this number would be great. I enclose an example for better comprehension. If you get only one size of symbol in the legend you can't really interpret this kind of map, so in my opinion this would be quite useful. Getting as many symbols in the legend as on the map would be, as you point out, quite useless as well.

#5 Updated by Giovanni Manghi over 12 years ago

julie - wrote:

Hi,
The idea is to get only a few example of symbols with different sizes in the legend. You usually get three, but being able to set this number would be great. I enclose an example for better comprehension. If you get only one size of symbol in the legend you can't really interpret this kind of map, so in my opinion this would be quite useful. Getting as many symbols in the legend as on the map would be, as you point out, quite useless as well.

I agree, moreover in the case you want represent (for example) cities with proportional symbols (so not making classes) it is likely that in the composer you want to have just a few, but still it is needed to use the "scale size field" to render them in the canvas.