Well today I had hoped to get the revised maps of Cromwell Gorge out. Unfortunately a mistake was found with the positioning of one of the aerial photos, which you can see reflected in the wrong position of the riverbed (light blue) as seen in the lower left of the image below. Fixing this has…

One of my favourite ways of illustrating the changes at Cromwell is this “bathtub” analogy in which a clear water representation of the lake as it exists today is overlaid over the top of the yard as it historically existed. As with all of the georeferenced historical imagery we are using for these maps, it…

In a number of locations in the Cromwell Gorge some remnants of farm or orchard properties can still be found today. This contrasts with my earlier portrayal of the Gorge as a sterile barren place. The use of the historical imagery in georeferenced form is driving these discoveries. The first two photos are the maps…

Here are samples of the side by side maps. These will be produced alongside full size versions of both types of map, this one is just for an easy comparison. The reason for having the disclaimer on these photos is that the aerial photography will not perfectly align so that in places, misalignment is readily…

So after a lot of tidying up and adjustment I have started revising the maps from Clyde to Cromwell. The reason for all this photoshopping is I have felt that having the original aerial photography as a background is better than trying to draw a lot of features on a map that aren’t a complete…

So what you can see here is part of the Gimp project for all the aerial images for the Cromwell gorge. So a few days hard work has seen all the aerials get put together and the bulk of the work needed to merge the 1962 aerials with the georeferenced Linz aerial photography has now…

I think a reasonable effort has been made to show where the lake is today as distinct from some of the other areas where old black and white aerial footage has been rendered.

So a lot of hard work, a lot of fun, and this is just a beginning, there is going to be a lot more tweaking to get this all done this week. And I am prioritising everything to get these maps finished this week.

So this layer mask thing turns out to be really simple. Here’s what about an hour’s work this morning has achieved with one out of seven large images (which had already been overlapped yesterday) and one small area at the middle left. In other words I have taken the images I had yesterday and just…