Sunday, 25 March 2018

Main North Line [11F]: Addington 6; Otago Central Railway [62B]: Km Pegs 2

So Addington is being more or less recreated from scratch. Doing the adjustment in the middle part (Addington North as it is called in my computer) covering the Main North Line going north to Riccarton was actually relatively quick and easy to fix, as with all the linked layers, moving one moved all the others, and no scaling was needed as the amount of movement needed was relatively small. The problem is, the other two extremities going east and west on the MSL have to, in effect, be hung on each side, as everything has to line up and be as smooth as possible joining up on the edges. So I have been working since then on the western side, starting with the middle part and adding things onto the left hand side of it, the base imagery and followed by the aerials that are needed to do this. 

The first aerial, 2345-B-3, is actually needed for the middle part at the extreme left hand edge, just a little tiny sliver on the side of 2345-B-5 because it doesn't quite reach the boundary of the geojpeg for that part. The rest of B-3 will make up the West project, as soon as I finish getting it set up for the North part, I then save the North project as West and then add in the rest of the stuff for West. It takes time because even on my main computer with 24 GB of RAM, these are big files for Gimp to handle, and so moving stuff around is slow work. The biggest advantage has been to be able to copy in layers from the previous versions of Gimp projects which saves a lot of time rescaling and rotating the layers from scratch. So it will come together a lot quicker than the projects last week, and I can use my second computer with 16 GB of RAM to do the rendering at the same time as working on the main computer to move the layers around. But it will still take until sometime next week to have it all back together again.

The rest of today has been working out the issues with the published articles in the NZ Railway Observer to write a complete list of them, which is currently being assembled as another post, and to inform the actual letter that will be sent to the the editor of NZRO; and doing a km peg list for the rail trail, using their street view imagery and marking the pegs on a Google MyMap. Right now I have discovered two 70 km pegs at Ngapuna. This raises the question that the rail trail trust has been putting in missing pegs and if so how accurate can they be assumed to be. The reason for doing these km pegs on a map is mainly to inform the discussion about the editing of my articles in NZRO. It does look like the rail trail trust could be taking pegs out and putting them in because I have not yet found one single half kilometre peg anywhere along the trail to date, but in a few locations I have spotted half km pegs with numbers attached to them. If the rail trail trust are putting in pegs the question is just how accurate their measurements are and perhaps they would like to explain the two pegs at Ngapuna.

Saturday, 24 March 2018

Otago Central Railway [62A]: Kilometre Posts on the Rail Trail

The Otago Central Railway maps incorporate full mile post indications for the entire length. The positions have been derived from various information in the chainage books for the line and by estimation these positions could have an error of plus or minus 100 metres.

Recently I have obtained additional information from Geoff Mackley that has enabled me to locate all of the kilometre and half kilometre pegs on the Taieri Gorge Railway up to 45 km.

The kilometre pegs for the rail trail are visible in the Google Maps Streetview data for the line. Due the onerous terms of Google Maps I believe I cannot release these locations under the Creative Commons license for the maps project. I therefore am creating two separate resources to show the locations of these kilometre pegs:

2. A separate layer in my maps which can be turned on and off as required. I will use this for internal purposes but it cannot be published under the same license as the rest of the maps.

Currently in order to get this aspect of the project started I have added a few km pegs from the first section of the trail from 64 km at Middlemarch as far as Ngapuna at 70 km. The remaining posts will be added at the same time as the overall map revision, which is currently (starting from Cromwell) up to Clyde.

Main North Line [11E]: Addington 5

Well, Friday has been a whole lot more mucking around to make various adjustments to all of the Addington stuff, mainly in the area of adjusting the masking for the partial images. This has resulted in needing to re-render all the partial map tiles which is a relatively slow process. Hence the maps have not been ready in time as expected. There are still more adjustments needed where some of the tracks don't line up, so it will be several more days before mapmaking can really get underway. Here are a couple of sample images that many readers will appreciate for their historical context.

The familiar present day view of Addington with a few extra things drawn in for context.

The historical context with present day roads and tracks.