Wednesday, 8 January 2020

Palmerston North Gisborne Line [0H]: Volume 5 Progress Update 8

On January 4th we commenced production of maps for the main line corridor of Volume 5, which is the Palmerston North Gisborne Line (PNGL) being 390 km from Palmerston North. Progress rates so far has been as follows:
  • Day 1: 0 - 26 km in 1 hour
  • Day 2: 27 - 50 km in 1 hour
  • Day 3: 51 - 136 km in 5 hous
  • Day 4: 137 - 227 km in 5.5 hours
  • Day 5: 228 - 294 km in 1.5 hours
 As you can see, productivity has varied a lot but has particularly shown an increase in the last day or two. This is the first large corridor where we have used the Linz aerial photography backgrounds for maps and we struck some issues with alignment of some of the layers that didn't match up the aerial photos, most notably the road layer (which is supplied by Linz as well). These layers were obviously drawn for small scale maps. The net result being with our large scale maps the alignments of roads needing to be extensively adjusted and this slowed down the earlier days of production.

Because nearly every map in urban areas was needing to be corrected we made a decision that on aerial maps the roads would only be displayed with their names and not with the actual physical paths being displayed as lines. On the diagram maps the lines would be displayed. This proved to be relatively easy to implement in Qgis. The result has been no need to fix the alignments except on a small number of maps where it has been a feature displayed on the aerial maps such as a bridge that has not been in alignment. 

On Day 4 although productivity does not appear to be as high as Day 5, we output a set of 16 aerial maps and 8 diagram maps for the Napier railway yard. For the diagrams, there are 2 for each physical area, which is the new and old rail tracks. The Aerial maps have 4 for each physical area, being the old and new tracks and the 1973 and 2015 aerial photo backgrounds, the 1973 ones of course being mosaic tiles from our Gimp project that covered the Napier and Wairoa railway yards. The time needed to compose each view and then change the various parameters to produce the 24 maps total is what slowed the production down on Day 4.

Day 5 has taken us all the way to Wairoa which is only 100 km from Gisborne. We now will have to take a pause to complete some other work, mainly importing the mosaic tiles for Wairoa that were previously created and then outputting the required number of maps for Wairoa, which has in total four different historical generations plus the contemporary generation. We also need to do some other work so things will slow down for the rest of the week but the overall PNGL map generation should be finished by the end of the week.

Below is the complete map sequence for Napier.