Questions tagged [rule-based]

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15
votes
3answers
1k views

Controlling rule-based labelling using PyQGIS?

Following on from this question: How to turn on/off all labels of all layers in QGIS, OP mentioned in his comment that he uses rule-based labels. I tried searching online as to how these types of ...
9
votes
1answer
831 views

Visualizing layer using categorized AND graduated styles in QGIS?

I have a layer with road segments that come in five different classes and each have a value. I am trying to get a graduated color for the values (say, light blue for low and dark blue for high values) ...
8
votes
1answer
217 views

cumulative atlas in QGIS 2.14 and above?

I have a question about something which I think is possible but just can't get my head round it, and haven't found any answers online. I'm using $id= @atlas_featureid in QGIS 2.14 to create an set of ...
7
votes
1answer
120 views

QGIS can't detect negative values?

I'm working with the last version of QGIS (3.8.3-Zanzibar), and I'm trying to represent a Rule-Based Symbology from a CSV file with the following rules: And the data from the prcptot column is this: ...
5
votes
2answers
4k views

Rule-based labeling in QGIS

I'm trying to label visited countries in a world map shapefile, what is wrong with my rule : if( "Visited" = 'yes', "NAME", NULL)
5
votes
2answers
482 views

How can I apply a style rule to multiple categories? (2.14 and above)

I think this used to be more straightforward in earlier QGIS versions, but with more powerful rule-based styling (great development) I am now a little confused as to how to apply a rule to multiple ...
4
votes
1answer
83 views

QGIS Draw by rule

I have a point layer with several colored dots. Each dot represent a find of a bumblebee species. E.g. red is B.terrestris yellow is B.hypnorum. In my attribute table I have a column named "nest" (...
4
votes
1answer
2k views

Changing symbol size using the “Size assistant” in QGIS?

I need to change symbol size of a categorised shapefile. For this I tried using the Size Assistant (in the style menu: right click > change size > Data defined override > Size assistant) However my ...
4
votes
1answer
190 views

How to return array from label offset expression? [duplicate]

I am trying to set the x,y offset of layer labels based on a data defined override. What I'm trying is the following: CASE WHEN name is 'Brooklyn Bridge' [3.5, 0] ELSE [-3.5, 0] END However this ...
4
votes
1answer
171 views

manage qgis rule based styling duplicates

I am new to qgis. When I am using rule based styling, duplicates for some reason show all the matching symbols and not only the first match rule's symbol. How do I make show only one symbol even if it ...
4
votes
0answers
78 views

QGIS rule based symbology for rasters in Atlas?

I'm making species distribution maps and have got the Atlas working perfectly using a polygon layer to show the quarter degree grid cells for species observation records. I have ~ 250 species. Problem ...
3
votes
2answers
356 views

Label OSM polygons above a certain size?

I'm wanting to label polygons on a map that are above a certain area. These polygons are dervied from open streetmap and consist of either ways or multipart polygons ie If polygon is more than 160 sq ...
3
votes
3answers
2k views

Categorization with multiple values- QGIS 2.18

I'm trying to represent 2 columns in polygon layer. I've tried to do it with the rule-based style but didn't understand how to do it. This is the attribute table of the polygon: I've tried to use ...
3
votes
3answers
3k views

Using 'max()' in expression with QGIS?

I want to make a rule-based style on the maximum value from a field. I set my expression like: max("fieldname") It returns every value instead of only the maximum one. Can anyone tell me the right ...
3
votes
2answers
238 views

QGIS style polylines with alternate colours

I have a bunch of shapefiles with multiple polylines. Each consistst of 5 up to 30 polylines. I would like to define a style which colours them alternating two colours. When I use the Categorized ...
3
votes
3answers
327 views

Show all points (airports) in featured country only

I need to generate maps showing all airports located in a featured country. My airport shapefile has over 8000 points, so I need to remove those that are irrelevant. Example: When Sweden is featured, ...
3
votes
1answer
238 views

How to automatically assign specific ColorBrewer ramp to polygons so that no touching polygons share the same color in QGIS 2.16

I'm creating a series of reference maps that need to differentiate between administrative regions within a country. I created a new color ramp using ColorBrewer Dark2 with 8 categories. My ...
3
votes
2answers
477 views

Displaying map labels over coordinate grid in QGIS?

My grid overlaps labels placed on a map. Is there a way of forcing the labels to be displayed in front/on top and the grid placed behind the text? Despite looking I cannot find a solution. Using ...
3
votes
1answer
142 views

dynamic legendlabel for a rule-based style

I have a rule-based style that is linked to a print-composer. In that composer I activated the atlas-function with a filter. Because of that filter the outcome of the rulebased style varies. Is ...
3
votes
1answer
81 views

Nested rules in QGIS 2.18

I work with QGIS 2.18. I have a polygon shapefile with two atrributes: id (unique for each polygon) and type. I visualize the shapefile using the "type" attribute, but I would like to add a nested ...
3
votes
0answers
68 views

SOL help in QGIS: rule based styling to show timestamp increase via gradient

I have some polygon data from a tractor that shows it's route among other things. It has a timestamp column which I'd like to use to show the route in which the tractor drove through the field via a ...
2
votes
6answers
131 views

Rule based coloured background for labeling in QGIS

I am a newbie working on QGIS 3.6 / Windows 10. I need to label a polygon layer which is categorised by colour. (pls refer to attached pic as a graphical reference) The labels need to have a ...
2
votes
2answers
59 views

Displaying 2 different color lines based on 2 different table attributes in QGIS?

I have a line shapefile that has a bunch of data and it is broken down into different features which is assigned a different number. It is then styled on the rule based approach so each feature gets a ...
2
votes
2answers
241 views

QGIS Atlas map composition to show only points inside Polygon?

I want to create an atlas map where I have some 40 polygons, 100 points and 200 lines as different shapefile. Now I want to automate the atlas map preparation for each polygon and needs to show the ...
2
votes
1answer
131 views

Categorizing multiple values_multiple atributtes - QGIS 2.14

I have a problem with a polygon layer. Its an equipment and services layer... I want to aggregate different types of services in similar legend, like this: For example, these four : "Ensino ...
2
votes
1answer
245 views

Categorizing multiple entries in QGIS?

I am trying to categorize a polygon layer with several buildings, by the number of floors. I want to aggregate by classes like this way: 1 floor = 1 to 2 floors; 2 floors = 1 to 2 floors; 3 floors = ...
2
votes
1answer
48 views

QGIS styling a legend

I am a newbie working on QGIS 3.6 / Windows 10 I need to style a legend for map with headings and sub headings The main divisions of the legend item need to be subdivided into sub-classes i.e. The ...
2
votes
1answer
66 views

Catching signal when rule toggles (active/inactive) using PyQGIS?

I would like to catch a signal when a rule within a rule based layer toggles visibility. How to permanently check this layer.renderer().rootRule().children()[0].active()==True the same way we can ...
2
votes
1answer
157 views

QGIS 3 - Variables in rule-based rendering?

I'll try and lay this out clearly, I have most of it covered, but there's a very specific thing I'm looking for in the rules - whether or not it can be done and if so, how? Key things I have done and/...
2
votes
1answer
28 views

How to find objects which are styled twice (in rule based styling) in QGIS 2.18.10

I have the problem of a complex rule based styling (with 10 different styles and multi-line rules in each style) with several thousands objects. My problem is that the sum of all styled objects in one ...
2
votes
1answer
239 views

Is it possible to show all label on a polyline layer with minimum overlaps, by automatic changing of the font size?

My goal is the following: I would like to show every street name/label, without overlapping (the scale I use is <20000, and it is changing). The default label is curved, 8p, but if the software ...
2
votes
1answer
572 views

How to write a string based rule, e.g. If “Name” contains 'NRG'

I have created a field called 'Name' in QGIS and I wish to create a rule-based style for a gridded vector. The grids are either 'NEP1' or 'NEP1NRG' etc. with values to 5000+. I want a rule to colour ...
2
votes
2answers
163 views

Rotation field is missing in rule-based renderer in QGIS 2.6

I am trying to do rotation of point symbols in QGIS. I am working with rule-based renderer. In other types of classification there is a button advanced (for example in categorized renderer), where I ...
2
votes
1answer
133 views

Rule based styling with select-by-intersection syntax

I want to do rule based styling for a selection of gridded polygons dependent on their position relating to another layer. I want to show the polygon that a point feature based in an atlas falls ...
2
votes
1answer
321 views

Adding new rule by using QgsRuleBasedRenderer to existing one in PyQGIS?

I want to add new rules for a layer. However when I add them previous one(s) are deleted. Here is my code: layer = iface.activeLayer() symbol = QgsSymbol.defaultSymbol(layer.geometryType()) renderer =...
2
votes
1answer
206 views

Multiple rule based expressions with 2 layer styles in Atlas

I have 18 transects over a geographical extent and I am applying atlas to display a map for each transect. All is going well and I'm venturing into expressions and rule based rendering $ID = @...
2
votes
1answer
214 views

Create rule-based renderer from an existing renderer using PyQGIS

I want to make a copy from an existing layer in the legend and render it with a rule-based renderer based on the original layer's graduated symbol renderer. Then I will change its rule expressions, ...
2
votes
1answer
378 views

Rule based polygon fill in QGIS?

I'm really quite new to QGIS, I want to style polygons fill with raster imagws based on a attribute contained in the property table. What do I have to write in the description in order to get for ...
2
votes
1answer
68 views

Can qgis2web display rule-based layer style?

I’ve just made a map that has two layers: one that contains the polygons and other that contains points. For the last one, I used rule-based symbology where I define the size and colour of the points ...
2
votes
1answer
37 views

Possible to set color based on attribute while using 2.5D symbology?

I'm using 2.5D symbology to have my features display at different heights based on a certain attribute, but would also like the features displayed as different colors based on another attribute. Is ...
2
votes
1answer
77 views

QGIS raster rule-based coloring

I have a raster with different values (negative and positive). I want to color the raster based on a rule: All positive values have a certain color and all negative another. I don't want to use '...
2
votes
1answer
205 views

Qgis 2.18.14 - rulebased and categorized style in atlas

I am currently generating an atlas. I have four parts of a map, showed on each page. For the map I have a lot of polygons styled in different colours after category. Now I need to make a rulebased ...
2
votes
3answers
341 views

Rules within thematic maps in MapInfo

Is there a way to set specific rules when creating a thematic map in MapInfo? I would like to exclude the polygons that have too many of the items I want to represent from the thematic map (something ...
2
votes
1answer
207 views

Can I specify half-open scale ranges in rule-based QGIS layer styles?

In QGIS 2.16.1's rule-based symbology as well as in its rule-based labeling, it's possible to enable a "scale range" to which the visibility of the result of the respective rule (be it a symbology ...
2
votes
1answer
76 views

Rule-based rendering of one line with two line styles

I need to show parts of a network, which meet two criteria at the same time. So I would like to use the style of criteria 1 and the style of criteria 2 side by side (see picture). The problem is, that ...
2
votes
1answer
479 views

How to change rule-based Layer Styles all at once in QGIS?

Let's say I have a layer with buildings which is only shown when the scale is higher than 1:10000. When the scale is higher than 5000, I want them to show its function color (retail, residential, ...) ...
2
votes
1answer
43 views

Features color based on layer's color in QGIS

Is there a way to synchronize the selection color with a layer's color in QGIS?. Following this post https://gis.stackexchange.com/questions/111784/displaying-only-selected-features-on-map-in-qgis#= ...
2
votes
0answers
22 views

Moving individual labels & rule-based labelling in QGIS

I have been playing around with labels and came to a problem. Hopefully someone can pinpoint whether I'm doing something wrong or there is a systemic hurdle in Qgis. Are you allowed to move labels ...
2
votes
0answers
39 views

Save QGIS style created with espression string builder

I created a rule-based renderer with espression string builder, where I also use the function editor in Python. When I share the style (qml) file with others, I realized that the Python function I ...
2
votes
3answers
264 views

Multiple overriding rules for styling in QGIS 3.4.0

I am a total beginner to QGIS and still struggling with the basics. After a quick research on this forum I could not find the answer to my current issue. What I am trying to do is to colour the ...