New Zealand Rail Maps Project Development Report – May 2022

During the past month the Project has focused, following the mid-April field trip, on completing Volume 11 maps for the Main South Line corridor from Lyttelton to Oamaru and all branch lines thereof. Subject to the adjustment of boundaries referred to in last month’s report, Volume 11 will now start just south of Rolleston, or approximately 35 km, and continue through to Mosgiel, at about 394 km. This enables the whole of Christchurch to be in one volume, Volume 10, the southern boundary of Volume 11 being set to make the total distance covered in this volume around 1000 km including the main line and all branches, with the southernmost 1000 km (main line and all branches) being placed in Volume 12.

All mosaics have been completed except for Oamaru itself and possibly a couple of ballast sidings which may be added later following further research later in the year. The Oamaru mosaics are about to be started and will be added to maps within the next week or so. The work will then move back north. There is no current plan to move to completion of the full Volume 11 this year at least as work will then shift to Volume 10 and eventually back towards the North Island. But there will be full maps produced at the completion of the current V11 work to provide full coverage for the first 220 km of main line and the branches off this part so an interim release will be made to the Volumes site for that which has been completed to date.

The webmaps site has not been altered substantially in the last year and some updates are being considered to take effect from the end of 2022. These include possibilities of adding the Linz basemap topographical layer as a base layer option, and implementing a layers selection slider to make it easier to choose different bases, especially aerial photo eras. The site would probably get a general redesign and the content would be updated to the latest available. It is probable in future the webmaps would only get updated annually. Apart from the above changes, being able to add aerial photography to the site in future is important as there is only a little aerial photography from Christchurch currently captured and adding all available which has been mosaiced into the various volumes for map production is something that has always been intended to take place as the current layers control lists various aerial photo eras. There are no other substantive updates planned to the site in the foreseeable future, for example no changes to the backend or any processing that might improve the general usefulness of the site like the speed at which tiles are retrieved and updated, nor in the current GIS-based tile creation process. It is known that various limitations do exist in the creation of tiles in that there are various issues with the way the tiles display in a browser, but addressing or fixing these would be a more substantial effort that could not be addressed without either updating the processing scripts in Qgis or changing to a completely different system of generating the tiles, and as such, no work in this area is planned for the present time. Updating the web maps site depends on the availability of time and resources over the rest of this year and this timeframe is reasonable for the amount of work needed given other time demands and priorities in the Project as a whole.

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