I have a raster layer with the day of the year on which we observe temperature above 15 degrees. There are large differences (image below):
I have vectorized this layer based on the Band including the information on day of the year, and now I would like to dissolve these into two different polygons.
The two different areas, seen in the raster image, are adjacent to each other so they will never become two different polygons with the simple
dissolve tool. However, the neighbouring pixels differ by more than 5 days, so I would like to dissolve these conditionally. More specifically, I would like to dissolve the individual vectorized pixel into one polygon if the neighbouring pixel does not differ with more than 5 days.
Is this possible in QGIS or eventually Python? If so, how?
According to Babel's comment, I potentially have to use
aggregate. My data is relatively large - with lots of these "heat islands" ranging from day of the year 65 to 345.
- I want to aggregate/merge/join adjacent polygons if their values of the field
- So I cannot use specific values like
"doy" > 130 AND "doy" < 136, as it would leave out the other pixels.
How can I use an expression that allows me to aggregate neighbour pixels if their (
"doy" < 5)?