Sunday, 18 March 2018

Otago Central Railway [61B]: Finishing Maps - Clyde 1

So while I am working on the Addington mosaic, that is a pretty slow process with a lot of downtime waiting for Gimp to resize images, the best part is with another computer doing only that and nothing else, I can carry on with maps on my main computer. And in actuality that is a dedicated VM which is where I do most of my mapping on different computers, because I can use multiple versions of the software, which I need to at the moment because of a serious bug in Qgis 3.0 affecting aerial photos. I need to use 2.18 to do most editing but I need 2.14 to do filtered layers editing because 2.18 deprecates that capability. 

So back into Central Otago and starting with Clyde and here is the 1976 aerial photography with everything else over the top of it.

Now this is a multi generational map that covers 1962, 1976, 1981 and later up to the present day. To make such maps work we have to be able to filter what is being displayed so that only the features like tracks, buildings, stations and so on for that timeframe are displayed. To achieve that I have extra fields for dates added to a lot of layers and run the same filter query on multiple layers at once and at the same time select the background aerial photography layers to be displayed and that is how we get to multi generational maps.

So Clyde is the westernmost area that is set up as multi generational, now I have to tidy all that up and push out the generations of maps for Clyde and then work my way eastward doing the same all the way along and just make sure all the stuff on the Google Plus collections is all nicely up to date and that we have maps up there for the entire line.

That will go on at the same time as Addington mosaics simply because it is an efficient use of time with the delays for making the mosaics while the computer does the hard work on those huge Gimp projects to make the aerial images for that part of Christchurch. I have almost completed Addington West now, I just have to mask off the area that I want from the Retrolens aerials and then save back the geojpegs for Qgis, probably finish that tonight. Then Addington North and Addington East to start on.