Monday 23 March 2020

NZ Rail Maps Project Development Report [2020E]

Here is our fifth project development report for 2020. These reports give a general overview of the whole maps project for the year 2020.

As has been outlined in previous posts in this series as well as general blog posts, we started this year on the assumption it might be possible to cover the entire set of 12 volumes in 12 months. The first volume (Volume 5) ended up 10 days behind this schedule but we thought it might be possible to catch up a bit and have the second volume completed in only about three weeks. But in fact it will take about 8 weeks to complete the second volume (Volume 6) so not only have we not caught up to the schedule, we are even further behind than we should be.

The reason for Volume 6 being behind schedule is that it covers a big urban area - Wellington - which has a large amount of history associated with it, as well as having had a lot of rail served facilities like the big Wellington yard and various branches, closed sections, depots and sidings. To give reasonable coverage to the suburban area we have had to intensify the coverage of the first 32 km from Wellington to Upper Hutt and as of this date, 6 weeks in, we have only just finished mapping that relatively short distance. We still have, however, another 140 km of route to cover to reach Woodville. It gets easier to do this because north of Upper Hutt, everything thins out a lot. However, we still expect it will take until early or mid April to complete the entire volume, and as that date approaches, we will become increasingly more keen to see this volume completed as quickly as possible.

With the completion of two volumes in close to four months and the need to have a healthy life balance in the allocation of time, we are now looking at a more realistic completion timeframe of up to two years for the 12 volumes. We feel that the NIMT (Volume 2) and some of the South Island volumes will take a bit longer to complete. We will continue to push ahead at a reasonable pace because we still want to have some sort of goal to aim at, otherwise this will never get finished. So the actual deadline is a bit more flexible, but right now we are still looking at about April 10th to complete Volume 6 at the moment.

The slowest part of the process is the historical mosaics which give us a look at the way things used to be in the past, which provide actual maps in the GIS that we can trace stuff off. Various economies and improvements have been effected in map design and production that will follow through into all future maps to make more efficient use of time going forward. The most important change is to accept impossible-to-avoid misalignments between the aerial backgrounds and the vector layers (the layers that show most features such as main lines, sidings, roads etc) by removing the expectation that vectors will always appear in exactly the right place on the aerials.

Volume 6 currently has 96 distinct map views for the 32 km of main line completed so far (in other words, an average of 333 metres of track in each view). There are 96 diagram maps and 354 aerial maps (although some of those are in fact historical maps of Wellington from 1900, rather than aerial photos). So 450 individual maps have been created so far. In Volume 5, there were just over 1000 individual maps created. We could expect probably at least that number in Volume 6 despite the significantly shorter corridor length.