From a picture it's very hard, because it's never exactly 1:1 scale.
The image is a CAD drawing - very very accurate - the PDF is a vector file (rather than a resolution dependent bitmap) - rasterize it so that a know dimension (preferably a long dimension like the Wheelbase) is 1:1 at a given resolution.
The image is a CAD drawing - very very accurate - the PDF is a vector file (rather than a resolution dependent bitmap) - rasterize it so that a know dimension (preferably a long dimension like the Wheelbase) is 1:1 at a given resolution.
1 min work = sub mm accurate result.