Questions tagged [calculator]
Related to a "field calculator" interface for modifying field attributes.
18
questions
2
votes
1
answer
53
views
Raster calculator expression which includes the "STATISTICS_MEAN" value from the raster properties
I'm looking for raster calculator expression which includes the "STATISTICS_MEAN" value from the raster properties. How can I build the expression, that the value is automatically adapted?
I ...
- 81
1
vote
1
answer
51
views
Copying field expression field calculator
I would like to know, how I can see the code behind a attribute field in the attribute table of a shapefile layer in QGIS 3.16.
I have created a new data column with a specific code used in the field ...
- 83
0
votes
0
answers
25
views
Averaging raster layers in QGIS, values changed, but image looks the same?
I am trying to average two raster layers together, but am getting results that are really confusing me, which is making me even question if an average is actually what I want to do to begin with. I ...
0
votes
0
answers
28
views
Updating string field with a path by using Field calculator . Version 3.18.2
Us it possible to update newly made string type field (column) with a path to a file on a local drive by using "field calculator".
I tried with first defining type of field as "String&...
- 525
0
votes
0
answers
47
views
Error when calculating NDVI using raster calculator in QGIS
I tried to calculate the NDVI with the Raster Calculator in QGIS but got doubled (see image) and distorted results. I have a problem only in QGIS as SAGA works normally. Does anyone know what is ...
0
votes
1
answer
15
views
Clip slope raster for values outside of percent grade range
I have a slope raster, but I would like to remove values (or make them no data value shading) outside a range which makes them too steep. I tried looking at the raster calculator, and I am not sure ...
- 13
1
vote
1
answer
114
views
Summing all rasters in folder using Python
I have a folder containing many raster files (.tif). I want to sum all of the rasters in this folder into a single output raster using Python in Jupyter Notebook. I have been able to use GDAL command ...
0
votes
1
answer
238
views
Unable to sum raster files in R using raster package
I am trying to sum all of my raster files (over 500) from a single folder in R, using the raster package, but am encountering an error message I cannot figure out how to solve. I am trying to use to ...
1
vote
1
answer
204
views
Unable to use gdal_calc from gdal to sum raster files
I am trying to run the following line of code from Anaconda Prompt to add all all of the raster files in a directory/folder together using gdal:
for %f in (*.tif) do gdal_calc -A %f -B result.tif --...
1
vote
0
answers
39
views
Rasterize multiple polygons and calculate average
I have a vector layer that contains many overlapping polygons, each containing a "Value" in the attribute table. I am trying to rasterize each polygon as an individual raster layer, and then ...
2
votes
2
answers
760
views
How to get directory from filepath in QGIS action
I have in QGIS layer that contains filepath (e.g. D:/file/28238/pic/D4D3-06_1.png) and I would like to get directory path only like D:/file/new/28238/pic.
Is it possible to do by expression in field ...
- 31
1
vote
0
answers
27
views
QGIS 2.14.8 - Illustrate Multiple Lots [closed]
I am having trouble illustrating multiple properties on QGIS.
Basically I want to illustrate multiple properties/polygons based on their identifying fields - lot and plan.
Can anyone give me an ...
- 11
3
votes
2
answers
115
views
Copy and transfer only the maximum values of data from one column to another in the field calculator
In the Attribute Table there is a field with the diameter and width of the pipe. I want to transfer all the data from this field to a new field. While in one line there can be several values of the ...
- 43
1
vote
1
answer
102
views
Syntax to add attributes in a line in the Expression String Builder
I have several columns with certain values, here's an example:
| Apple | Banana| Orange | Pear | Expected result
| 1 | 1 | 1 | 1 | red
| 1 | 2 | 2 | 1 ...
- 72.4k
1
vote
1
answer
4k
views
How to calculate polygon areas in acres or square miles instead of feet?
I have a layer in State Plane NAD83. When I use "Vector|Geometry Tools|Add/export geometry columns" or Field Calculator they both create the area in feet. What if I want acres or square miles? Thanks
...
- 11
10
votes
4
answers
6k
views
Getting latitude/longitude in Degree Minute Second (DMS) using QGIS Field Calculator
I have come up with the following expression to convert 5.1234 to 5°7'24.24"
toint($x) || '° ' || toint((($x) - toint ($x))*60) || '`' || substr((tostring(((($x) - toint($x))*60) - toint((($x) - ...
- 109
2
votes
2
answers
3k
views
How to select only areas bigger than x acres?
I would like to create a new shapefile from another area shapefile. The new shapefile should only contain all areas that are bigger than 5 acres (10.000 m²).
How do I do this?
- 2,161
3
votes
1
answer
544
views
Sum up area left "underneath" polygons in QGIS?
I have an area shape layer and multiple other area shape layers. Now I would like to calculate how much space (square kilometers or percentage of area) of the polygons of this area layer is NOT ...
- 31