Overlay Webmaps Development Preview – Greater Christchurch [3]

This post is a series on the development of a new web maps preview for the Greater Christchurch area. The creation of this preview is currently intended to be used to promote the utility of the maps for the Greater Christchurch area, to give access to historical and current day information about the Greater Christchurch, to promote rail development initiatives in Greater Christchurch, and to evaluate the suitability of the technical structure of this particular preview for deployment of the full web maps site.

This is a general progress report as to where things have got to since the last update. It was resolved to try and include as much coverage of Greater Christchurch as possible within this preview, since the delays in creating it had led to the suggestion that some of the region might be excluded in order to meet a deadline. However it is clearly understood that a deadline is necessary because other commitments exist in light of the whole project and the completion of this project is holding up other related work that is not directly part of this project but falls more within the objectives listed in the first paragraph of this post. Hence close attention is being given to a balance between a reasonable completion timeframe and making the preview incorporate as much of Greater Christchurch as possible.

After the second week of preview creation work, the focus has again been on creating the aerial photography necessary for the completion of the Greater Christchurch web maps preview. No maps have actually been drawn in the past week with all work being done on the aerial photos. Quite a lot of new aerial photography for the 1950s has recently been added to the Retrolens site which has impacted on parts of the Christchurch aerial mosaics that are being prepared in various areas. The mosaics for Middleton through to Islington have just been completed and the overlaps between different sections are currently being adjusted before they are imported into the GIS. Hornby to Lincoln is almost complete and work is about to commence on Islington to Burnham and Addington to Kainga.

The next progress update should take place a week from now and it is confidently expected to be able to report that all aerial mosaics have been completed and map drawing will be well underway. Accordingly, the new timeframe for completing the web maps preview has been extended to approximately the end of the third week of November.

Overlay Webmaps Development Preview – Greater Christchurch [2]

Last time we talked about the process of developing a preview for Greater Christchurch and it was hoped we could have it ready in a few days. Now we are a week into this process and although good progress has been made on this task, it’s been necessary to juggle whether to spend time getting the preview reasonably correct before publishing, or just push it out and fix the mistakes later. This meant inevitably the timetable being pushed out.

The conclusion so far has been to fix as many issues as can be reasonably achieved within a capped time frame, and although that time frame keeps getting pushed out, it is only a few days at a time. So far the deadline for completing the map data is now at the end of October, from which it is probably about another three days to a week to prepare all the layers for uploading, and create the custom home page Javascript code to display them.

As usual, the most time consuming aspect is to fix various aerial photo layers, and so far this has been performed in Heathcote, Hornby-Lincoln, Christchurch-Addington and Middleton-Sockburn. As this is written, we have the complete set of aerial coverage for Middleton that have been corrected and have just finished drawing the 1967 layout of Middleton. From there, checking the other generations available at usable resolution (1961, 1975 and 1984 in this case) for changes (which are mainly expected to be in private sidings) follows. Then after that, repeating that process for Sockburn, where the reference generation is 1980, with 1961, 1972-75 and 1984 also being available.

After that it is on to Hornby and Islington which may require more mosaic work. By the time we have finished to Islington, it might be time to decide whether to just create the preview at that point, with only the MSL from Lyttelton to Islington completed (around 20 km) completed, and then add other GC coverage later. It is reasonably certain that it could take weeks to add all of GC and that pushes too much into the planned timetable for other maps previously planned. So completing GC on just a part of the MSL that is within Christchurch City, is the most likely scenario for the preview for the purposes that we want to use it for at the moment.

Overlay Webmaps Development Preview – Greater Christchurch

Good afternoon. Here is this week’s update summary for the NZ Rail Maps Project. So far, in order to aid the development model for the new web site, we have created two different development previews: Volume 1 (North Auckland Line) and Volume 6 (Wairarapa Line). These have reflected several development levels proposed for the maps:

  • The Volume 1 preview demos a map style that has two layers, being selectable from Diagram layers and one era of aerial photography, both available at various zoom levels.
  • The Volume 6 preview demos a map style that has around 16 layers, being selectable from Diagram layers and 15 eras of aerial photography, all available at zoom levels 12-19. It is an advance on the Volume 1 preview by providing for a much greater range of aerial photography in web maps. This has subsequently been modified by adding a transparent overlay for part of the Wellington railway yards.

Last week we started work on a new preview originally proposed to be of Wellington station. With further consideration, we have now changed this to be a preview of Greater Christchurch. The intention is to add four transparent overlays and thus make it possible for users to overlay various levels of symbology on top of their chosen era of aerial base maps. Using the Greater Christchurch area instead enables more evaluation of it by people we work with in Christchurch and with considerably more information included in all of the maps, it will be quite detailed and comprehensive and thus showcase very well what is possible to be achieved in this web maps system. In other words, it will be good advertising 🙂

As we are currently reviewing the completeness of information included in the Greater Christchurch maps and there is a fair amount of editing/updating needed, it will take several days to complete all of the source layers to the preferred standard. Mostly, there are several yards and sidings which have only been partially completed to date, and these will have to be added. Once this work is complete, the generation of the web maps will be relatively straightforward.

As we detailed in previous posts, once the new preview has been completed and any issues corrected, we will be in a much better position to determine what is the best development model going forward. The next stage after that being the development of automated scripts to speed up much of the maps generation from the various volumes. At that point the focus will go back onto actual production versions of Volume 1 (still requiring some digitising work), and Volumes 5 and 6 (mostly completed in a previous format).

So look forward to the Greater Christchurch preview, we expect it to be very good.