Questions tagged [values]
The values tag has no usage guidance.
67
questions
28
votes
3
answers
58k
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Reading attribute values using PyQGIS
What is the way to get the information contained in the attribute table, say in column 2, row 2 using PyQGIS?
- 299
11
votes
1
answer
2k
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Creating predefined values in field using PyQGIS
I would like to make programmatically (with Python) the same thing than we can do directly in QGIS when you create a list of values for a field.
I would like to create a new field and specify a list ...
- 557
8
votes
2
answers
2k
views
Finding the minimum value of different columns in QGIS
I'll try to calculate the minimum value of four different columns in my QGIS table like:
The min. value would be 1,50286 in the first row.
Is there any expression or tool to find the minimum value ...
- 183
7
votes
2
answers
407
views
Classifying raster layer by number of equal values in given area using QGIS
I am using QGIS 3.16.12 - Hannover. I have a binary raster layer which consists of 2 values, either 0 or 1 (in my screenshots, 0 = black, 1 = white). The 1 values are scattered throughout the layer in ...
- 113
5
votes
1
answer
193
views
Connecting points to the two closest highest values grouped by category
In a points layer with the fields "POP" (corresponding to the population value) and "CATEG" (corresponding to municipality id), my goal is to connect the points of each ...
- 2,419
4
votes
1
answer
419
views
Return a set of unique pixel values in a raster with PyQGIS? [closed]
I am trying to test whether a value exists in a raster against all the values present. I am using pyqgis (Python 2.7) in in QGIS 2.14. I have found a number of ways to get point location values and ...
- 131
4
votes
1
answer
383
views
QGIS 3.22: problems with dropdownlists (attribute forms)
I discovered the nice possibility in QGIS to create dropdown lists in a field, with which I (should) choose in a simple way one of several species (in my case) - while entering new features. I tried ...
- 483
4
votes
2
answers
1k
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Replacing all "NULL" values in multiple rows with "0"
I am looking for a way to replace all "NULL"-Values throughout multiple rows/ all "NULL"-Values in an attribute table. The table is from a SHP-File (shapefile).
Is there any easy ...
- 41
3
votes
1
answer
971
views
Setting a default value in a QGIS creates empty field
I use Qgis 2.18.3 and tried to set default values in new column in a existing shapefile via the layer properties as described here: Setting a default value in a QGIS field
or here
How to set a default ...
- 931
3
votes
1
answer
469
views
Invert raster's min with max values (as well as the in between values) and vice versa using R
I have a raster with pixel values, 1 to 255 (no decimals). I want to invert their values in a way that pixels with value 1 will get value of 255, pixel with value 2 will get 254, pixel with value 3 ...
- 1,093
3
votes
1
answer
1k
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How to create a Value Map widget type to select multiple values (checklist) from the dropdown?
I have a polygon layer that represents tree/shrub planting sites that were done. As part of the attribute table, I have fields representing things like tree density, species, soil work, tree size, etc....
- 43
3
votes
2
answers
2k
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Reading raster values in points gives back a generator object instead of actual value
Given a raster TIF file and a point feature class in a geodatabase, I am trying to extract the values of the raster on the points and add them as a new column on the point feature class. I am using ...
- 1,236
3
votes
1
answer
252
views
Importing CSV results in NULL values for decimal column in QGIS
I am importing a .csv file and one of the "integer" columns ("ZVH Density") is all NULL values when imported as a Delimited Text file. Whole numbers import (known through trial and ...
- 31
3
votes
1
answer
162
views
Creating buffers with values, and finding areas with high value overlap of these buffers
I'm working on a project where, essentially, I'm measuring threat levels based on geospatial patterns. I have different groups with higher or lower threat levels based on the distance from their ...
- 31
3
votes
1
answer
95
views
QGIS attibute form with value relation avoiding table
Is it possible to use some expression or text containing a values list for the dropdown control to display them?
The goal is to use a short list of values and not have to create a related table for ...
- 2,419