Rasterizing only the border of a vector polygon

Question

I have a layer of very 3 x 3 m square polygons. I would like to rasterize just the border of the squares, so the interior cells just have 'nodata' values, and you can see layers below it. When I process this with rasterize in QGIS, the whole square comes out black. Any way to do this?

Answer 1

1. Convert polygons to lines.

2. Buffer the lines.

3. Rasterize the buffer.

Left: original with initial polygon (red hached), line around polygon (black) and buffer (blue). Right: rasterized (black), initial, red hached polygons included for reference/visualization purpose: