I did a quick test (qgis 3.10 / postgresql 12 / postgis 3)
If I am opening a table for editing in qgis, I have no problem editing the same row from a psql prompt. It seems to me that the only locking that is going on is at the moment the row is stored.
So - I can open the attribute table for the layer "sns" in qgis and set comment to 'something' for the ...
To remove gaps and overlaps you should use the Topology tool. The Topology tool helps validate your data based on different rules you choose appropriate.
One of the many rules available in that tool is: (features) "Must not Overlap".
The tool has an "Error Fix" button that let you zoom to the error (in your case, an overlap) and let you choose what to do - ...
This solution works using the Attribute Editor, but does not work through the Attribute Table.
Select the records you want to update to NULL
Open the Attribute Editor from the Editor toolbar
If you have more than one feature you want to update, select the top row (this makes any attributes you edit update all selected records)
In the field you want to ...
You could replace any empty strings with another string from the field calculator.
Using python, where STATE_NAME is the field:
If you mean Null not as a string you could try using a codeblock:
if x =="":
Under field, replace(!STATE_NAME!)
i am not really sure i understand your question, but it seems i had a similar problem: a large qgis project with different print layouts each representing a different print frame of a collection of 4 maps. layouts would overlap for about one inch, and i had to manually move the labels so that they would not be cut by any layout border. i have solved this ...
If I understand correctly, you are trying to remove overlap between polygons. I would suggest looking at the ERASE and CLIP tools. If you are talking about slivers (gaps) between polygons, you can use the align to edge tool on the editor toolbar, as well as the snap tool. If you can provide screenshots of your workflow and examples of your issue I may be ...
This is not how the reshape tool works. Actually, you do not select any node by double clicking: you just create a duplicated point in your new border, hence the green color (try to double click anywhere outside the polygon, you will get the same green cross).
To expand your polygon, your first and last point must be inside the orignal polygon
Before right ...
You can write to selected bands using the indexes keyword.
If you want your array to contain only zeros you can also create a new numpy array. This way you don't need to read any data at all.
import rasterio as rio
import numpy as np
with rio.open ("/src.tif", "w") as img:
band = np.zeros(shape=(img.width, img.height), dtype=img.dtype)