I'm having trouble in QGIS with the symbology. I can classify and categorized my data, but I cannot with the graduated symbology?   I've try different format in Excel, and I can't find the problem here.
36559
I m working on a project on QGIS. I have a point shapefile vector that represents my store. In the attribute table, i have bunch of data such as size, unit per transaction and most importantly store turnover. When I want to graduate the symbology, the turnover isn't present in the list I can choose from. Does someone know why, and how to fix it?
96497
Just trying to run the following code already given in the pyqgis cookbook to create graduated colors symbology (as in example with 2 classes)  I define the source info for the shapefile but when I run execute the code within my test-plugin, it just adds the layer without classifiying. Just adds as usual, all polylines appear same.  Any solution or working code/method?  link to code in cookbook   from qgis.core import  (QgsVectorLayer, QgsMapLayerRegistry, QgsGraduatedSymbolRendererV2, QgsSymbolV2,QgsRendererRangeV2)  myVectorLayer = QgsVectorLayer('C:/my_test_shape_file.shp', 'test_shp_file', 'ogr')  myTargetField = 'target_field' myRangeList = [] myOpacity = 1  # Make our first symbol and range... myMin = 0.0 myMax = 50.0 myLabel = 'Group 1' myColour = QtGui.QColor('#ffee00') mySymbol1 = QgsSymbolV2.defaultSymbol(myVectorLayer.geometryType()) mySymbol1.setColor(myColour) mySymbol1.setAlpha(myOpacity) myRange1 = QgsRendererRangeV2(myMin, myMax, mySymbol1, myLabel) myRangeList.append(myRange1)  #now make another symbol and range... myMin = 50.1 myMax = 100 myLabel = 'Group 2' myColour = QtGui.QColor('#00eeff') mySymbol2 = QgsSymbolV2.defaultSymbol(myVectorLayer.geometryType()) mySymbol2.setColor(myColour) mySymbol2.setAlpha(myOpacity) myRange2 = QgsRendererRangeV2( myMin, myMax, mySymbol2, myLabel) myRangeList.append(myRange2)  myRenderer = QgsGraduatedSymbolRendererV2('', myRangeList) myRenderer.setMode(QgsGraduatedSymbolRendererV2.EqualInterval) myRenderer.setClassAttribute(myTargetField) myVectorLayer.setRendererV2(myRenderer) QgsMapLayerRegistry.instance().addMapLayer(myVectorLayer)      @Kelly's code works perfectly.   However I noticed that both the code (one I have typed in my first message and yours in the 2nd message) DO NOT work in QGIS v1.7.3 but WORKS in QGIS v1.8.0. I think this was a bug(?) that already resolved in v1.8.0  And one more question;  Do you have any sample code for (natural breaks, Jenks) classification of the "numeric_attribute_field" based on given number of classes (i.e. no of classes will be a variable in the code, say "n", and I will pass that from the plugin GUI i.e. n = spinBox.value() )
16921
Can anyone help me in giving commands for commutative diagrams in LaTeX ? It doesn't seem to appear properly in the LaTeX guides that I have. A command for a simple triangular diagram with arrows associated to maps would be good enough, or maybe some appropriate reference.
58366
I have a map with graduated symbology, with 328 unique values. I would like to add a legend to my map (as in the picture), illustrating that light blue indicates low values and dark blue high values.  I have done this in ArcGIS before. Is there a way to do this in QGIS as well?
42139
I have been trying to teach myself QGIS by using this forum and others to help. Most of my questions can be answered by downloading plugins that are available through 3rd party repositories but for some reason I am not able to connect with these. Anyone have any ideas why this is the case?
9899
QGIS allows for opening very many different file formats.  Some of these are directly editable. It is possible to open the data/file, immediately edit the data in QGIS, then save back to the original file.  Many formats can be opened/read, and at the same time it is possible to save/write to that format BUT these require that the data is saved into a second format before editing is possible. This is fundamentally different from the first situation.   The question is what data formats are directly editable by QGIS (the first situation as opposed to the second)?   Reasons a list is helpful...  I think that sometimes QGIS doesn't handle this whole issue terribly well - for example in the past I have had some Excel files look like they are editable but the process ultimately fails - which adds confusion.   Notes at gdal.org provide some information, but it can be very difficult to distinguish between the two situations above - formats which are directly editable, and on the other hand formats which can both be read and written (but aren't directly editable).  It is helpful to have information about QGIS (or ogr) version in answers.
72240
I have a polygon feature dataset, and an attribute from a different table that I join (one-to-one) within QGIS in order to symbolise the attributes as a choropleth map. However, not all polygon fields have a matching field in the table of numerical attributes, so there are some null values when producing the graduated symbology.  From my research, the most common piece of advice in this situation is to include a copy of the polygon dataset (or some other background) that defines a default symbology. This works because the null values are not classified in the graduated symbology, so one can see "underneath" them. I have attached an image of exactly this. The dark grey features do not exist in the join table (mb_percentile_isochrones_all), but do exist in the boundary polygons table (mb2013_wgtn). So I need two instances of the mb2013_wgtn table in order to show the "no data" features.    However, this does not seem elegant to me. Much more intuitive would be to define a null value symbol. Perhaps this could be perfectly transparent to be consistent with what currently exists, or perhaps it would be some kind of muted grey—whatever the user wants. The point is, at present one needs two different layers in the contents in order to handle the symbology of null values. This means that to change the symbology of all your features at the same time (say, if you want to increase the width of all borders), this has to be handled twice: once in the properties for the feature with the graduated symbology, and once for the "background" layer that handles the null symbol.  Is it possible to define a "null" value symbol without using a "copy" of the same layer used for the graduated symbology, in QGIS (2.6.1)?
5930
I am using QGIS 2.6.1 and have worked in an Excel file database (which was actually converted from a Shapefile). I have managed to convert it as CSV file and load it into QGIS (displays data fine) but I have trouble to convert it to a shapefile.  I can view it but I can´t add or alter data in this file. I think I have to save it as a database.   Any clues how to convert the xlsl-data to a database and finally to a shapefile?
66980
I do not understand why there can be in QGIS different CRS for project and for layers. I have worked previously with subsurface petroleum software and there CRS &quot;stuff&quot; was lot more strict in that sense that data was almost always tied to the CRS of the project. Will the data be prone to inconsistency if there is different CRS for project and layers?
70041
I'm new to QGIS and have been seeing what it can do for me – seems good. I imported shape file data from a UK Ordnance Survey data file and saved the file in a new folder. It was very good, doing all I wanted. I exported and got exactly what I wanted ( a tiff image).   I closed the file in order to try a new experiment. When I went to re-open it I got a dialogue box saying 'Handle Bad Layers. I don't understand what is at issue and what to do.
56805
I work on QGIS 2.2, and I am unable to edit my attribute table to change the field type from string to double.  I have gone through several tutorials. - I can not run the table manager plugin, probably because its latest version is for qgis 2.0, (well it appears broken on my plugin manager UI).   I am unable to edit my layer so that I can use the field calculator (as several tutorials stipulated). I am not versed with python to use the python console
77525
After a few hours I am about to give up on finding a kind of documentation for the QGIS Python API that actually works/gives the correct information. It is obvious that there is no actual code documentation besides the one for the C++ API which differs from what works in Python. Ok, there is the help()-function, too, to get information about classes which is more than ust tedious to use. As an entry point, I thought I could use the tutorials/cookbook: . Even simple things like adding features does not work the described way in the current QGIS Version 2.4.0-Chugiak (there is no addFeature-function for example).  I wonder how working with the Python console and writing plugins makes sense under such unfavorably conditions.  What sources can actually be used to lookup and learn the Python API for QGIS for current versions?
92596
Does anyone know where the Processing menu moved in QGIS 2.4? Specifically, I am trying to install the LAStools box for QGIS following these instructions:
50250
I have some layers in my project and I would like to alter their styles, since ranges of values for underlying columns have changed.  Normally it would require to enter each layer style settings separately and trigger "Remove All", and "Classify" button, however I would like to execute it from the code.   I found such method for graduated symbol:  renderer.updateClasses(layer,0,bins)   ,however I'm having trouble to find corresponding method for categorized symbol class  Is there any way to do this from pyqgis without the need to specify the layer style from the scratch (create category, label etc.) ? Some equivalent of "Classify" button from below screenshot:
76461
I'm having an issue with QGIS version 3.2 Bonn. For my class, a question asks, "What city corresponds to row number 1713 for the Colleges and Universities shapefile?". I'm having issues answering this, because each time I load the shapefile into QGIS, the attribute table order is randomized, giving me a different city each time.   How can I open the "default" version of the attribute table for this layer, so that the order of rows is not randomized each time?
100324
On a map I used different symbols to indicate different structures. I used  to draw on the screenshot of a map website. I defined three types of symbols:   \tikzstyle{ARA} = [blue,regular polygon,regular polygon sides=3, draw, shape border rotate=180,inner sep=0pt,minimum size=10pt,fill=blue] \tikzstyle{wfluss} = [-&gt;,blue,thick] \tikzstyle{probe} = [red,diamond,draw,inner sep=0pt,minimum size=10pt,fill=red]   I want to have the legend (i.e. the part explaining the symbols) to be in the caption, i.e. that the red and blue symbols are explained in the caption.
121664
After I did styling my vector data set to be classified by graduated circle and categorized by type, it appears beautifully consistent in the map canvas as shown below:   But when I create a print map layout and after adding the map, I add the legend and it come out ugly inconsistent like this:    So, I would like to ask for help to make the legend in the map print layout consistent as the legend shown in layer panel. I use the latest version QGIS 3.10.2 64bit.