For the last few years I have been drawing the best ever maps of the Otago Central Railway. Right now I am drawing the best ever maps of the Nelson Section. What have both those got in common? A lot of readily available online documentation, including the all important aerial photos.
Does this mean every closed line in New Zealand can have maps this good? Unfortunately the answer is no. Many closed branch lines are in areas with limited aerial photography coverage. It's just a fluke that we had such good coverage of the Cromwell Gorge and most of the Nelson Section. Mainly it has come about from the fact there were other features there that were of interest. In the case of Nelson, the forestry in the area, and in the case of Cromwell, the hydro development.
Simply put, I don't expect to get such good detail for a lot of other lines and I don't expect they will be able to be drawn with as much detail as the current maps of Nelson Section I am doing are. That doesn't mean I won't put in the effort for these maps - I am putting that in just because the aerial coverage is good enough to show up a lot of details that were missed when I was drawing maps in GE. But there have been on the Otago Central some features that got missed because there was next to no aerial coverage in some areas, and the same also being true of the NS.