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Geographic Information Systems

Questions tagged [rule-based]

The tag has no usage guidance.

66 questions
info Newest Frequent Votes Active Unanswered
1
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0answers
19 views

Detecting checking/unchecking of rules in a rule-based rendering using PyQgis [on hold]

Is it possible to programmatically detect checking/unchecking changes of a rule in a rule-based rendering ? I found no indication of existing signals .. I got lost reading QgsVectorLayerRenderer ...
2
votes
0answers
28 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 ...
1
vote
1answer
13 views

Rule for labeling ways not being part of OSM relation in QGIS

A brief overview of what I want to achieve: Create a map showing all cross-country ski trails in a specific region with some customizations/styling on them. The data come from OpenStreetMap ...
0
votes
0answers
34 views

Symbology or style to separate layers

I have a layer i.e. vegetation, i can split this layer in different colors using rules or categories i.e. light green = grass, darkgreen = trees. Then the colors appear 'nested the layer. When i make ...
1
vote
2answers
40 views

Altas with rules on different layer than the cover layer [duplicate]

I need to generate an atlas based on a polygon shapefile, but I'd like to see just what is inside the polygon itself. Maybe with rules that involves other shape's attributes. Any suggestion?
1
vote
1answer
25 views

Need an Expression for rule based styling in Qgis using attribute(get_feautre()) and ILIKE combined

I Have 2 Layers: I want to Filter Layer 2 by an Attribute from Layer1 for some rule based styles. I Currently using following expression to realize that: "C1" = attribute(get_feature(‘Layer 1', '...
0
votes
0answers
17 views

How to add rules to the topology from a .rul in ArcPy

I am trying to create a new topology using and ArcPy script and I have a lot of rules inside a .rul archive. The function to do that is: arcpy.AddRuleToTopology_management(out_topo, rule_type, in_fc1,...
2
votes
1answer
39 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 '...
1
vote
1answer
50 views

Rule-based rendering in qgis2web client is not working

I made a simple map with polygons of the staates of africa and used the rule-based renderer for different colors to tint them. When I tried to load or export this map with qqis2web I didn't get ...
1
vote
0answers
64 views

Rule-Based Styling not working in QGIS?

I'm trying to create a shapefile I can use as a template for a breeding bird survey. The basic gist was that each species has a two letter code and a colour depending on the BTO listing. Each bird is ...
0
votes
0answers
51 views

Multi line rule based labels in QGIS [duplicate]

I have created rule based categories for my symbology, and I would like to have multi line labels to go along with these. At the moment, I have written some expressions for specific cases, in which a ...
2
votes
1answer
77 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
71 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
3answers
137 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 ...
1
vote
0answers
37 views

QGIS - Rule-based Symbology - Added Ranges do not carry over Legend entries [closed]

When I add ranges to a rule, under Rule-based Symbology, the auto-populated (or modified) legend values do not carry over. To fix this, I would have to manually change each line in the legend ...
2
votes
2answers
153 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 ...
1
vote
1answer
33 views

Add a scale or category to a rule which is only applied to points within original subset in QGIS

I have subset a shapefile of points to only include those having a value of (for example) 33 in the variable "Bout" using a rule based assignation: Now I would like to apply a sub-category to that ...
0
votes
0answers
13 views

Automatically add Points to Line Symbol

I've got a printed Map. The points marked with arrow in the picture only appear, when line feature crosses a coherently polygon feature. You can see an example in the picture. When the line feature is ...
0
votes
1answer
49 views

Rule-based styling window freeze in QGIS 2.18.16-22

While I was working on cartographic files (QGIS 2.18.16 - Linux Mint 18.1) using the rule-based styling window, suddenly the window and the program freeze and I can not longer work on editing. By ...
2
votes
2answers
50 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 ...
3
votes
0answers
52 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
1answer
92 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 ...
2
votes
1answer
172 views

How to add 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
26 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
0answers
96 views

Set a rule for grow region in eCognition

I am using the grow region algorithm in eCognition sofrware in order to merge my candidate class. I want to set the rule : two candidated objects are merged only if the length/width ratio of the ...
9
votes
1answer
620 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) ...
3
votes
2answers
341 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 ...
2
votes
1answer
166 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 ...
1
vote
0answers
158 views

Automatic refreshing of Styles and legends in QGIS?

I am a new QGIS user. I come from an Arcgis background, but in my current work for a public administration I must use QGIS for interoperability. As an ArcMap user, I am used to certain "comforts", ...
1
vote
1answer
330 views

Rule based labeling in rule based styles

I have got a layer with distance vectors between polygons. This layer has a rule based style where I can check each polygon to show only the vectors with contact to the polygon. Each vector has as an ...
1
vote
1answer
836 views

QGIS Rule-Based Styling Expression

I have a point layer with 2 columns, company name and short name. I have many company name entries but fewer short name entries with some of them being categorised under the same alias. See below for ...
4
votes
1answer
1k 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 ...
2
votes
3answers
290 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 ...
3
votes
2answers
168 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 ...
5
votes
2answers
3k 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)
1
vote
1answer
351 views

Managing rule-based renderer in PyQGIS?

This is my first project in QGIS and I'm also quite new to Python. PyQGIS is more than a challenge for me! I found code in How to programmatically set a rule-based renderer in QGIS? to set a rule ...
2
votes
1answer
190 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 = @...
1
vote
1answer
125 views

How to treat PosgreSQL array fields in QGIS rule-based styles filters

In a PostgreSQL/PostGIS DB I have a table with an attribute declared as a 1-dimensional integer array INTEGER[] holding a value like {1,2,3,4,5}. Now I would like to build a rule-based style and need ...
2
votes
1answer
115 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
205 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 = ...
8
votes
1answer
195 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 ...
3
votes
2answers
330 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 ...
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 ...
4
votes
1answer
148 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 ...
5
votes
2answers
436 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
151 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 ...
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 ...
2
votes
1answer
179 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, ...
1
vote
1answer
1k views

QGIS: Style-“Rule-Based” [closed]

Style: Rule-Based Please be informed that the Add Categories to Rule under the "Refine Current Rules" does not filter in accordance to the selected layer that you have chosen. Instead, all ...
2
votes
1answer
222 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 ...

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