Diary of creating a city

[Nobby-W]

@#%$*~

So, with a bit of sodding about I've managed to extract some coastline data from the OSM data set. Japan proved to be a bit tricky as it seems to be impossible to download it without bringing across the whole of Europe and Asia as well. This took an oblique round trip through a shp-osm converter, maperitive and Inkscape to get out a SVG of Japan's coastline. New Zealand, Japan and Java have similarities in their geography due to being on active plate boundaries, so I cribbed their coastlines to get bits to make up the coastline for Ilthar.




The data sets are big enough to herniate my laptop, which has otherwise done sterling service and handles the Vetawa map with aplomb. I'm told that my Z420 will actually play nicely with registered memory (even though this is not officially supported by HP), which allows it to be twinked out to 128GB for a few hundred quid. For another couple of hundred I can get it a 2TB SSD. In a more extreme case I could get a secondhand Z820 or Z840, but that's going to cost a grand or more, so I don't want to do that.

In the meantime I'm trying to find a way to generate contour lines, from which I can abstract mountainous regions.

Even though I'm just trying to extract a little bit of information from them, these geospatial datasets are ginormous and I need to wrangle the whole lot to pull the snippets out. For the first time in about 15 years I have to say I think I need a bigger computer. In the meantime I'll keep trying to get them apart with what I've got.

 

[Nobby-W]

More progress on Northern Ilthar

After a bit of faffing about I found a GIS suite OSGeo4W (https://trac.osgeo.org/osgeo4w) that included a contour generator. There is height map data at 30m and 90m resolution available through the Shuttle Radar Topography Map (SRTM) project, and I could use a utility called gdal_contour to make a contour map. I've used the 100m contour line as a proxy for hilly terrain and then bastardised the contours to remove the hair. They're very detailed but look a bit rough in practice at this scale.

The geography is based on the western end of Java, rotated 90 degrees, with bits of other stuff grafted onto it. I used map data from Indonesia, Japan and New Zealand as they have various geographical similarities being sat on the edge of active tectonic plate boundaries. I'll also do higher mountains from the contour data at some point but what I really need is the lay of the land to plan the city. I'll also put in some rivers, other major urban areas in the region and major transport networks.

GIS is a big old rabbit hole and I'm not sure how far I really want to go down it.

In related news, I've figured out how to tile art boards in Illustrator so they overlap, which makes for a great way to split a map into individual pages while working on it as a whole.

 

[Nobby-W]

North part of Ilthar

This has the major geographic features, plus settled areas (not all smaller ones shown) and a high-speed rail or maglev network.

 

[Nobby-W]

Art boards

I figured out how to do overlapping art boards in Illustrator the other day, so this morning I tried it out on the Moseli map. This works just fine for printing page-sized chunks of the map, although there is still the bug where it renders the railways around the edge of one of the maps. As the railways are currently rendered as dashed lines, converting them to outlines for rendering should solve this, I think.

Unfortunately, Illustrator has a limit of 100 art boards per drawing. This is probably enough but there are definitely more than 100 8.5x11 tiles on the whole map. The good news is that one can convert rectangles to tiles, so a database of the tiling for various purposes can be kept on a hidden layer. It also means that (in theory), versions tiled for 6"x9" or letter could be maintained from a single source.

 

[Nobby-W]

Topology of the drawing structure

So, we have the problem of scaling a significant number of businesses and other locations on the map. The original layer structure was getting pretty unwieldy - separate hierarchies for alleys and streets, parking and other open spaces, buildings and labels. Adding a single building or other location was a location in searching through three different hierarchies, finding where to drop the parts and then finding they had wound up in the wrong hierarchy.

The amount of concentration and checking to ensure stuff wound up in the right place was getting very disruptive to the act of doing any creative work on the map and slowed work down to a crawl.

The new experimental version has the map split up into the indivudual suburbs and most stuff hanging off a hierarchy within the suburbs. There are a few globals: Roads, land railways and waterways, but these are not very complex and amenable to clippting for rendering individual tiles. The roads get used to make the blocks and then hidden.

Making the blocks consists of taking a land or suburb base (now suburbs where I have them set up) and building a cut-out mask from the roads, open spaces and alleys. These can be used to drop the spaces out of the city blocks. By colour coding the base spaces and alleys one can select them using the magic wand tool and copy them into the build area for the blocks. The actual operation uses the pathfinder tools.

It works reasonably well. One can then use the magic wand tool to select and hide the components. You can hide and reveal hidden objects by selection or globally. None of the template object need to be revealed on the final map as they're all used to cut out blocks.

You can also lock stuff you're not working on at the top suburb level.

It's getting a little tricky to describe what I'm doing without getting into the nitty-gritty of how it works.