Next Aerial Batch

A request has been sent to Archives New Zealand for a new batch of aerials. These will cover from Galloway down to Wedderburn, with a couple of Clyde as well. The ballast pit at Chatto Creek should also be included. The specific photos requested are:

1. R18344219: Survey 71, Run C, Photo 4
2. R18344220: Survey 71, Run D, Photo 3
3. R18347187: Survey 1745, Run X, Photo 11
4. R18347185: Survey 1745, Run V, Photo 10
5. R18347185: Survey 1745, Run V, Photo 11
6. R18347184: Survey 1745, Run U. Photo 13
7. R18347184: Survey 1745, Run U. Photo 14
8. R18353409: Survey 3858, Run C, Photo 17
9. R18353410: Survey 3858, Run D, Photo 16
10. R18353415: Survey 3858, Run I, Photo 2
11. R18353415: Survey 3858, Run I, Photo 3
12. R18353409: Survey 3858, Run C, Photo 18
13. R18344440: Survey 112, Run H, Photo 7
14. R18344439: Survey 112, Run G, Photo 6
15. R18353407: Survey 3858, Run A, Photo 24
16. R18353408: Survey 3858, Run B, Photo 24
17. R18347178: Survey 1745, Run O, Photo 4
18. R18347178: Survey 1745, Run O, Photo 5
19. R18359828: Survey 8319, Run B, Photo 3
20. R18359829: Survey 8319, Run C, Photo 2

Although my preferred era has been the 1960s, aerial photography from around that period is hard to locate in Central Otago which apparently doesn't get photographed as often as some areas do. The reason there was so much around Cromwell-Clyde would be due to the hydro development which was a long standing plan for the area. Some of these aerials are therefore from the 1970s and others are smaller scales that will be unusable at 300 dpi, they are only being used in order to pinpoint the location for rescanning at hi res. Unfortunately the last batch of scans confirmed that these 300 dpi images are nearly unusable,

I expect probably only one more batch will be needed to get down to Middlemarch and from there I will consider whether to get a batch to cover the Taieri Gorge stations. There will not be a great deal of map making until I can get those hi res scans so I expect things will appear to go slower until the end of year holiday period.

It is possible I may get some hi res scans of the 1992 Cromwell Gorge set done at some point for further reference but this is not such a priority as the rest of the line and enough time has been spent looking at this area already.

Galloway, Chatto Creek, Omakau, Lauder, Auripo

So as we move on down the line, then I am about to order the next batch of scans for the line. How usable these are as I have mentioned, is difficult to know.

The current map of Galloway, showing aerial photo footprints. Since Survey 1452 only covers Alexandra to Clyde, I will have to find a new survey that is suitable, at around the same time, to work up the Manuherikia Valley. Galloway was only a small station so there won't be much detail to copy.

Chatto Creek was also a small station with not much to see. However, it also had a ballast pit, the bridge for which can be seen to the west of Bridge 76. It should be possible to pick the details of this up on aerial photography, as I understand the ballast pit was still in operation until the 1950s or 1960s.

Omakau was a more substantial station, which at one time had its own engine depot and turning triangle for locomotives. It will be useful to pick up this detail to add to the map.

Just east of Omakau we have the phantom curves. I don't think these warrant any further investigation; it seems clear enough that the surveyed corridor was never used by the railway at all.

Lauder was small enough that I don't expect to pick up much there but it will be useful for completeness.

I hope to be able to find further aerial proof of this deviation near Auripo. The nearby Auripo station is another small halt.

Otago Central Railmaps

Things are going a bit slower at the moment, for a variety of reasons. I'm busier in term time with work and study commitments.

However there is also a change due to Archives New Zealand's change in their pricing. I have budgeted to spend not more than $50 per month on aerial photos. Previously this would get me 40 scans at 600 dpi but because of their price increases, they have now chopped this to 20 scans, and worse still, have chopped the resolution of those scans to 300 dpi. If the image is a very good quality then you can still see enough detail at that resolution to be useful. If it is less in quality then the 300 dpi scan is useless.

Because of that, what I get out of each batch will vary a great deal and sometimes it will be very little. The last batch had one hi-res scan of the 1980-1990 Clyde yard, which produced a useful outcome although incomplete. The 300 dpi scan from 1979 of the same general area was good enough to add some additional detail but not really much at all. The rest of the scans have been of little use, including the ones of Alexandra. They serve only to pinpoint areas I will have to pay more for later to get scanned at a higher resolution e.g. 1200 dpi. The photos of the Cromwell Gorge taken just before the dam filling started in 1992 were of little use.

Archives New Zealand have advised they can do high resolution scans on the basis that the first scan will cost $50 and each subsequent scan in the same batch will cost $10. So I will have to batch up a pile of images for hi res scan and get them all done in one go. For obvious reasons that will happen as soon as I have a big enough batch - say $200 worth. And that itself will have to wait until I have identified enough low-res areas of interest. So for now I will be heading down the line to find all the other stations and yards and sidings etc which are of interest and will just have to see what turns up in each batch, which may not always be a lot. In the meantime there is still a bit of tidying up of what I have already to do. 

So while the maps may appear to go slowly, I expect that I will probably put in a big batch of hi res scans towards the end of this year and then be able to make best use of having the holidays available to push through a lot of progress all at once.

Archives New Zealand's new charges in relation to aerial photos

On the 1st July 2015 Archives New Zealand introduced a new scale of charges for remote research services. The key points of these charges as they relate to aerial photographs include:

• The base fee of $25 per half-hour has increased to $50
• The scan resolution that is defined as "low resolution" has been decreased from 600 dpi to 300 dpi.

Since I have determined that 600 dpi is the minimum resolution suitable for the aerial photos I am using (around 1:10000 scale), I am now faced with either paying a lot more money to Archives, or making do with the lower resolution. The indication from resampling the images I already have at 300 dpi is that I will struggle to pick out some of the detail that is visible at 600. It indicates that 600-1200 dpi is the optimum resolution for these around 1:10000 aerials but it also depends on the print size. It is pleasing to know that the option for scanning these contact prints has worked out from a technical point of view, compared to scanning from the original film, which Opus charges an enormous scale of fees for.

The fees for high resolution copying start at $30 although there is a volume copying rate of $10 that may apply to subsequent scans. The $50 fee is also payable as a minimum charge. When this fee is applied to low resolution scans it includes 20 "free". I am currently seeking clarification from Archives as to the application of the scale of charges for high resolution scanning since I may inevitably resign myself to obtaining a limited number of high res scans at the higher pricing. If the charging scale works out that there is significant advantage in getting a number done together then they will be batched. The use of the high resolution scans is going to be limited to Volume 17 otherwise it just ends up costing too much. So everywhere else will be low res except where there is free or cheaper high res coverage available.

The chainage chart referred to in a previous post turns out to have 24 pages, therefore it would only cost about $50 to have it scanned. I am planning to set up the request for this next week. Meanwhile tidying up the traces from the previously obtained aerial photography continues.