Thursday 15 March 2018

Main North Line [11A]: Addington, etc

Having completed sorting through aerial photos of the MNL and now having a complete set, the next task is to start doing stuff with the photos. The first thing that will happen is I will do a set of historical maps for Addington, as that is where the MNL starts. When I first started looking at Christchurch yards about three years or so ago I had Canterbury Maps coverage and I used to overlay it in Google Earth and then import the lines and shapes into Qgis. Even though those old layers still exist, I am going to redo it all from scratch and create mosaics for all the stations on top of current Linz coverage, because I can use the mosaic aerials when I publish the maps.

So for part of today I will have two computers both running Gimp to create the mosaics of Addington, which is both a MSL and a MNL station, being a junction. It is a very interesting location that like many other areas of Christchurch has seen huge change over the past 40 years. Doing two Gimps side by side is basically having one of them resizing and rotating as quickly and roughly as possible, and then the second doing the absolute minimum number of these operations to get a result that is as sharp and clear as possible, because every such operation reduces the final quality. 

I haven't forgotten the Otago Central Line but have just needed a break from it over the past few weeks but I will be pushing on with it today as well. I have to reorganise the aerial photography resources for it as well, and that will take some time to complete. But most of it is just editing the project files to find the new folder paths where the aerial photo collections have been moved onto a different server, and shouldn't actually take too long. 

The optimisation / VRT preparation script is going to be started fairly soon, maybe at the weekend, because I need to get on to the task of both making my life easier with fewer layers in VRTs, and reducing the number of images I need to keep copies of on the computer, because they are using up so much disk space. The Volume 10 resources are using 200 GB, Volume 11 we are only just starting on is 70 GB, and Volume 12 is 90 GB. However, an earlier series, Volume 7, is well optimised and only uses 3 GB. Volume 10 and 11 are expected to use a lot of space because the MNL and MSL both cover a lot of territory in Canterbury and pass through major urban areas. But I can't sustain the amount of space that some of these volumes are taking up because it fills up the disk and makes the backups too big as well. So this rationalisation improvement really has to happen, but it means more delays that will take me off mapmaking for a while.