How can I manually position these numbers for a better position in a polygon layer?
Following the suggestion of @Joseph, I solved the question by this way:
Assuming that there are already defined labels.
Step 1: created two fields; xLabel and YLabel, decimal type, length 20, precision 4.
Step 2: Layer Properties > Labels > Placement > Data defined, maped the X and Y fields in 'Attribute field' to match with the fields previously created xLabel and YLabel.
Step 3: (the only action to repeat for each problematic label - activate Edit): With the Move label tool dragged the label to the desired position. The new position is automatically recorded in the xLabel and YLabel fields.
You could use the easy custom label plugin to move them where you want. See my blog post for a longer example of how this works.
I suggest that you use a custom rule-based placement for each feature label. You do this by creating a label-placement rule associated a unique value that the feature contains (e.g a id, gid or any other field which is unique).
- Go to properties for the layer (right click layer and choose properties) and pick the 'Labels' tab.
- Choose rule-based labelling in the dropdown, and press the '+' icon.
- Filter on the unique value (in the example it is the field "id" and the integer 1). Choose offset from centroid and play around with the x,y values and quadrant placement until it looks good.
Repeat this for each point for which you want to manually place. With enough fiddling it should work.