Monday 30 December 2019

Map Development Levels [2]: Intermediate Level

In the last post we described the process of creating the maps to a Basic level. This post describes the second level of maps, the Intermediate level. The main difference between Basic and Intermediate level is that a printable PDF file is produced for each map volume.


For a printed format, like a book, the maps will have the tiles put into pages of a document in a way similar to the electronic format to enable intuitive navigation between pages of the document. The Project will only produce and distribute PDF documents that can be downloaded and printed out by an end user; we did consider online publishing but decided against proceeding with it. The PDFs should be able to be printed out and bound by any print shop, although we have not yet evaluated the real world feasibility of this. To make a printed format map easy to print or copy for casual use on a home computer or regular photocopier, the maps are purely monochrome ("diagrams"), using black, white and shades of grey, rather than colour elements. Consequently a large number of different symbols and line patterns are used, as described in the maps key. 
 
 The process needed to produce a PDF volume file is that data tables need to be compiled from various sources for each route to be included within the volume. The major amount of content is map tiles that are specifically designed to fit onto physical pages and to use the space on those pages to the highest level of efficiency whilst also being easy to navigate. These last two considerations in particular are what have led to maps being designed incorporating navigational aids such as arrows to indicate the direction origin and terminus stations of the particular corridor, as well as adjusting the map orientation so that the rail corridor always goes horizontally across the corridor (aligned more or less with the navigational arrows mentioned above) regardless of the actual direction by the  compass it is going in. Hence the maps always have a north facing arrow shown in the bottom left corner that rotates with the map tile and quite commonly, north will not be at the top of the map. 
 
We have had criticism made of this format by those who suggest that the top of a map should always be the northward direction. Whilst this paradigm may be appropriate to large format printed maps, it is not much of an aid in a situation where only a small segment of a map can be displayed at one time (as is the case in the static tiles format we use online) and where it is therefore necessary to quickly change to a new tile without losing track of orientation. Or to put it another way, you need to be able to be quickly align the way the map is displayed with the actual alignment of the corridor relative to the direction you are physically travelling in, and not to lose track of that when you scroll to the next or last tile. Having to produce all maps "north up" would not only make that potentially very difficult but also waste a lot of space on pages.

Whilst the maps used in a printed volume are the same as the diagrams published at a Basic level, they have to be regenerated at the size needed to work within the page format of a PDF. In a nutshell, whilst the format that is most useful for a phone or tablet is landscape orientation, the usual format for a PDF is portrait orientation. These differences mean that producing the PDF version of a map volume is not a simple cut and paste exercise.

The next post in this series will be made tomorrow and describe the Comprehensive level, which is the most time consuming step and accordingly, we are not doing maps at this level for all stations.