Can I make a multi layers pdf from a mapnik xml?

Question

I am playing with mapnik and trying to export multiple vector files as one pdf with multiple layers.

For the moment, my vectors get merged when rendering. Is there a way to keep each vector in a separate layer of my rendered pdf?

Answer 1

That's actually easier than what I expected.

The PDFPrinter needs to have its use_ocg_layers parameter set to True. The .finish() method implicitly calls the convert_pdf_pages_to_layers() method if use_ocg_layers is True.

The code looks like this in Python:

page = mapnik.printing.PDFPrinter(use_ocg_layers=True)
m = mapnik.Map(100,100) 
mapnik.load_map(m, "my.xml", True) 
m.zoom_all() 
page.render_map(m, "my.pdf")
page.finish()   # implicitly calls convert_pdf_pages_to_layers()