I am working with QGIS and am trying to convert a raster layer into a vector layer. I have converted it to a polygon from raster (image below), and then wish to dissolve this polygon into a single vector shape. This has worked for the majority of the shape, but at some longitude there is an error, and it only dissolves vertically but not horizontally (2nd image below).
Has anyone had this error before, or can anyone recommend a different approach to get a vector layer from a raster?
I have used the Dissolve function, and also tried the GDAL/Grass dissolve functions with no success.