Friday, 15 December 2017

New compositions [2]

Following on from the previous post about discussing where things can go after Otago Central I have been looking at aerial imagery available for North Canterbury (Waiau Branch and MNL) and Hawkes Bay / Eastland (NGL). At the same time I am also looking at Volume 12 completion (Kingston Branch and its various branches, but not quite as actively.

With the reopening of the MNL (the highway officially reopens today) it is opportune to look at completing those maps and with the discussion about reopening part or all of the NGL (and also a friend has just moved to Napier) that is also timely.

So I have obtained the aerial photography for the Waiau Branch route to add to the earthquake coverage of the MNL which I already have. The route of the branch is nicely covered by relatively recent 0.3 metre resolution imagery which is a nice sharp resolution, although somewhat washed out in appearance as it must have been taken on a very bright day.

I have aerial images of Waipara from 1972 which will be put into this Gimp project when I have some time and then it will all be detailed in due course. 

So here is the roadmap for Volume 10:
  • Waiau Branch all stations detailed (fortunately where the aerial coverage is not such a high resolution in a number of areas I have Les Dew's book to help out)
  • MNL using the earthquake coverage only except for historical detail of Picton and Addington-Rangiora already done AFAIP
  • Oxford and Eyreton Branches finishing the historical detail already done AFAIP
And that is all the work needed for Volume 10. Should be easy, right? Except that a lot of the Addington-Rangiora stuff is a mess because of multiple times the Christchurch stuff has been changed (project and data formats/structures etc).

I'm not going to give a timeframe or priority but let's say I expect to progress that in the first half of 2018.

Napier-Gisborne Line in Hawkes Bay also has nice recent 0.3m imagery all the way to the boundary. Here is some around Wairoa:

(Note the km pegs are not likely to be published in a volume or the official maps online as they are probably KRL copyright information and I can't be bothered at this stage contacting KRL to see what their views are.) This is an old project by present standards - last used nearly 18 months ago and still in EPSG 4326 so it has to be converted to EPSG 3857, since all the aerial imagery is in the latter CRS. 

On the Gisborne side the available aerial imagery is 0.4m resolution dating from 2012-13. Still reasonable - some of the older Linz stuff is 0.7m for the Otago Central so it's quite good at 0.4m. As it happens there is 0.1m coverage of some urban areas, which is Muriwai and the Waiapaoa Bridge all the way into Gisborne.

So here is a roadmap for Volume 5:
  • NGL may or may not have all stations detailed - I am not making a firm commitment even though I have good aerial coverage for practically all of them.
  • What I will make a commitment to is the historical coverage of Napier, Wairoa and Gisborne, plus the basemap stuff anywhere else along the way.
  • Sometime in 2018 (no firm dates of course).
And here is a roadmap for Volume 12:
  • After finishing the Otago Central Railway then the Kingston line and its branches but not at a full level of detailing. I will look at detailing any branch junctions and terminii and possibly Riverton but I won't absolutely commit to those as I haven't checked out the full level of available imagery and do know that for some of the areas good coverage isn't available.
  • Volume 12 will be finished probably in 2018 but I haven't decided the priority. It is highly possible it could just be rushed out as is (without any more work on Kingston Branch stuff than what I already have) and adding any more detail is just left for sometime further down the track.
So there is some kind of development roadmap going forward. 

The priorities are largely geared around communities of interest. The Waiau Branch has a significant community of interest with which I have historically strong connections although going back roughly 25 years since I had any significant involvement. I don't expect the same community of interest for the NGL or Kingston so they are much lower priorities. The MNL as a whole has significant interest because of the quakes but not enough to bother detailing the historical aspects of much more of it than the branch lines. Of course the Otago Central railway has the biggest community of interest and that has largely driven the intensive development of the maps for the area.

Getting the aerial photography for even the current basemap is a big step in itself - four separate downloads for NGL for Hawkes Bay because of the download size limit of 3.5 GB - and then picking out just the imagery you need and deleting the rest because it gobbles up disk space - I'm down to 50 GB of free space on a 2 TB disk volume pretty quickly. So a lot of work just for that. If I do Linz basemap coverage for every area that is a lot of work and I expect that I will. Have to start deleting some of those virtual machines I have been testing Qgis on. Now that I have a second computer at my desktop running Qgis as well I can work on two projects at once without using up the RAM on the mainpc running a VM. The second computer only has 8 GB of RAM but that will have to do as another 8 GB would cost $150 and that is just too expensive.