(Summary at the end for if you don’t want to read it all)
Hi everyone. So I’ve been interested in OpenStreetMap for a while, and I’ve been looking over it and lurking around the community forum.
Something I’ve noticed in Australia is inconsistency in city boundaries, as sometimes they are the borders of a metropolitan area, sometimes an urban area, sometimes the city proper (as in the main municipality which the greater metropolitan area is centered around, also called a local government area or council area), and sometimes they are just completely incorrect and not based on anything.
If you don’t know the differences between a city proper, urban area, and metropolitan area, a city proper is the area that a city actually has administrative power over, which here in Australia is commonly called a ‘council area’. The urban area is the entire built up area around that central city, and the metropolitan area is the city and all of its surrounding areas/suburbs which have close ties. Normally in Australia when talking about a city, people are referring to the metropolitan area; most people would say that Chatswood is in Sydney, despite it technically being in the city of Willoughby.
I’d like to explain why I believe all of the boundaries of cities in Australia should be changed to the boundaries of their city proper/LGA.
The OpenStreetMap Wiki states that: ‘An administrative “city limit” boundary is often mapped separately as a boundary relation tagged with boundary=administrative + admin_level=*.’ Another page on the OpenStreetMap Wiki states: ‘An administrative boundary. Subdivisions of areas/territories/jurisdictions recognised by governments for administrative purposes.’ Most Australian cities, for example, Sydney, use an administrative boundary tag despite using a metropolitan or urban area boundary. Sydney uses its Significant Urban Area for its boundary. So, despite using an administrative boundary tag, which is supposed to be used to show city limits (the municipality), it shows the borders of Sydney’s urban area. More than this, urban areas have no administrative or government function at all in Australia.
Another reason to change city boundaries is that Wikipedia tells us ‘…a city can be defined as a permanent and densely populated place with administratively defined boundaries…’. Again, many Australian cities in OpenStreetMap do not show their actual administrative/council boundary, which is inaccurate for the actual definition of a city.
Using the city proper as a city’s boundary will also be more consistent with the rest of the world. For example, when looking at Los Angeles’s city boundary, it shows the city proper and other areas which are commonly considered to be part of Los Angeles but are technically their own municipality with city status are listed as separate cities, such as Santa Monica. You can again see this in Birmingham, UK, where the city’s boundary reflects the city proper and not the entire urban or metropolitan area.
Another reason to change all city boundaries to their municipal ones is that some cities in Australia already are based on their city propers/municipalities, which means that not all cities in the same country are defined in the same way currently. For example, Brisbane’s boundaries are already set as its city proper, which you can see on the Australian Census website to compare. Also, Logan City and Ipswich again use city proper boundaries. Logan City and Ipswich are both part of the Brisbane metropolitan area, so if the boundaries were set in the same way Sydney’s were, Logan City and Ipswich would not be labeled as cities, but they are (and I believe they should stay that way, I’m just making a point that the way cities are defined in Australia is non uniform). Perth’s boundary is also its municipality at the time of writing this.
Another reason that cities should use their municipal boundaries is that some areas which should be labeled as cities are not. For example, Victor Harbor is labeled as a town despite being incorporated as a city. In regards to Victor Harbor, the City of Victor Harbor proper does exist in OpenStreetMap, and it is labeled as a municipality, while Victor Harbor as a town also exists within that municipality for some reason, and both are labeled as having ‘administrative’ boundaries.
There are also many instances in which other cities exist within another metropolitan area. According to Wikipedia, Parramatta and Liverpool (and a handful of other places) are considered cities, not just because of the fact that they’re municipality is incorporated as City of ____, but because the NSW Geographical Names Register fully recognises them as cities within their own right. But because in OpenStreetMap they are both considered to be part of the ‘city’ of Sydney, they are only labelled as towns, not cities, which they should be and could be if Sydney’s boundary was only its city proper. And that is not to mention all of the other municipalities which have city status that aren’t on the NSW Geographical Names Register, such as Blacktown, Canada Bay, Randwick, etc.
Something else I noticed was that sometimes borders are just completely inaccurate and don’t fit any definition of a city. For example, Adelaide’s borders do not match up to its city proper, metropolitan area, Significant Urban Area, or Urban Centre definitions.
To summarise, Australian cities boundaries should reflect those of their city propers—also called municipalities, local government areas, or council areas—because that way all cities can be defined in a uniform way and be consistent throughout the country, and when compared to other countries’ cities in OpenStreetMap. It will also allow cities which are not currently labeled as cities (some as municipalities, some as towns, etc.) to be shown correctly on the map. Some cities on OpenStreetMap are already shown by their municipal boundaries and some have completely wrong boundaries that don’t match any definition of their city.
Thank you for considering these changes and I can clarify if needed.