Saturday, 9 May 2020

North Auckland Line [0F]: Volume 1 Progress Update 6

Good morning. Work on Volume 1 as we know is waiting for Volume 6 to be completed. Earlier this week Volume 6 made a major advance and then we took a day's break from V6 and during that time we have done some additional work on V1 and also completed an aerial mosaic of the Auckland station and wharves using 1972 aerial images from Retrolens, which is part of Volume 2 whenever that is next worked on.

We are very keen to get to work on Volume 1 next week as we have to get back to work on Volume 6 to finish it with three small corridors waiting to be mapped and the maps produced for Volume 6 which will only take a day or two. 

Since our last update for Volume 1, we have completed mosaics for the North Auckland Line from Westfield to Newmarket, the Newmarket Branch and the Onehunga Branch, and have started on a mosaic project for the first section of Newmarket-Waimauku. In other words the first three tasks in the list of four for mosaics have been completed. However Newmarket-Waimauku is the most complex because it covers a total distance of 43 km from Newmarket and therefore it is a very long section and we will not be able to give continuous coverage even although we do have continuous 0.075m aerial coverage available for Auckland City the entire distance. We will have to see which areas do need coverage but there are continuous station and corridor surveys all the way out that we have already downloaded from Retrolens to create the mosaics.

In accordance with the "Basic+" definition for this project once we have the mosaic tiles we will not be putting in any historical information from them except two or three places, which are the Ellerslie Racecourse platforms (already done), Mt Albert Ballast Pit, and Swanson Deviation. We may reconsider if it becomes apparent any historical data can be added quickly without requiring a lot of time. However the usual problem is that mosaic project files quickly grow and reach an unmanageable size for processing (it can often take 2 hours to save a large project file) and then have to be split in multiple pieces. We would probably only seek to add additional historical coverage in a few places, and not at all at this stage of the project.

The section from Newmarket to New Lynn will be completed in mosaics today and we are currently downloading the files needed to cover the rest of the urban rail corridor out to Waimauku. However the highest resolution continuous station survey coverage only goes as far as Henderson. From there to Waitakere and beyond relies on corridor surveys and probably as there is far less history, the last parts at Kumeu and Waimauku will not be completed as a continuous mosaic section from Waitakere. Work will be stopped after completing Newmarket-New Lynn to allow Volume 6 completion to resume, and we will then be back into working on Volume 1 sometime next week.