Tag Archives: Helsinki

Directions of streets in Helsinki

A Shiny app that shows the orientation of the streets of Helsinki by district, and of the whole city. Data comes from Register of public areas in the City of Helsinki.

The whole exercise might seem a little silly (and probably is too) but if anything, it made me realize e.g. how the district of Viikki looks like a galloping horse when you look at its streets from this perspective.

Having done that, I used the Python library OSMnx to plot polar histograms. Here is a notebook where I tell how it went, and why Pasila is not where it should be.

Trees and areas

The city of Helsinki is home to quite a big number of trees. Trees are interesting living organisms, and their sheer existence makes your life better in so many ways. This is how I personally feel anyway.

Thanks to the newly opened Urban tree database of the City of Helsinki we can now look at trees’ whereabouts also digitally. Note that the database is not exhaustive, error-free, nor regularly updated. The coverage is better on trees growing along streets, less so on trees within parks, which I find understandable.

To start with, let’s take a sample of 5000 (10%) and plot them as points on top of the Helsinki district map.

Here we can start to get a general understanding of where Helsinki is as its greenest at street level. The southernmost green points fall on the island of Suomenlinna so imagine that you see the shoreline somewhere above those.

Where are the tree hotspots? A density map reveals that they are not far from the city centre; around Töölö bay and Hietaniemi cemetery, and in Kaivopuisto by the sea.

I was surprised by the number of different tree families, 115! Yet, the top 8 families are far more common than the rest: linden (Tilia), maple (Acer), birch (Betula), elm (Ulmus), rowan (Sorbus), oak (Quercus), pine (Pinia), and alder (Alnus).

Rowan trees are the most widespread ones whereas pines are very concentrated to SW.

How about the age of the trees? Data does not tell about the age very much at all, but a good proxy is the size.

Smallish trees seem to the most widespread. Their density is relatively high especially in the city centre which sort of sounds right; in recent years, Helsinki has been quite busy in rejuvenating its tree population. Note that only about 3% of the trees are missing the size info, i.e. the size is given as a NA.

While at it, I also checked which tree grows closest to where I live, and which one the most far.

Turns out that the nearest one is 150 m from my home door, on the bank of the Itäväylä highway. An Amelanchier laevis, planted last year.

The most remote one on the other hand was planted earlier this year on the southern shore of the Kerava River, 11 km to the North from here. The family? Thuja, my namesake 🙂 More exactly, a Thuja plicata, a Western red cedar.

These Thujas can become tall if all goes well. The Finnish name Jättituija (“giant Tuija”) reflects this fact. In North America where the species is native, its wood has been frequently used in e.g. Haida totem poles, few of which I only this week had the chance to see in British Museum, London.

With almost 50K items in the dataset, there is really no easy and practical way to show information from every tree at the same time. Instead, I decided to combine data with another open dataset from Helsinki, Valuable environments in the public areas of the city of Helsinki. This interactive web app shows, which trees are located inside these areas. The bigger the tree (diameter on the chest level), the bigger the circle that points to its location. Be aware that all text in tooltips and pop-up boxes is in Finnish.

R code is available here.

Streets of Helsinki

Helsinki streets on a map

Walking is fun, and there are always new ways to move forward, literally. Some people (not unlike me) have had this silly idea to walk all the streets of Helsinki, in alphabetical order. Johannes Laitila is one of them, and his blog is a good read (in Finnish). Recently Sanna Hellström, the head of Korkeasaari Zoo and former member of Helsinki City Council, mentioned in Twitter that since last fall, she had started to follow in Johannes’ footsteps.

Sanna’s tweet made me think about the size of her plan.

Spatial data of addresses of Helsinki are available from the city’s WFS API, via e.g. the key data site of Helsinki Region Infoshare. Of course addresses are not quite the same thing as streets but will do. Because addresses can refer to almost anything urban, I filtered them with a list of Official street names, the domain name of which tells something about the pragmatism of my home city; the name translates to Plans for cleaning.

The number of unique address names in my filtered data is 3788. The total sum of the geographical distances of individual addresses is 783 km (486 miles). There are some caveats though. Firstly, not all streets are populated by addresses from start to finish. In my home suburb Kulosaari for example, the two longest streets are Kulosaarentie and Kulosaaren puistotie. However, the former starts as a motorway exit road and meets its first address only after a few hundred meters. The latter is equally without addresses a long stretch from both ends. Secondly, distances are not calculated by the street level, so the meters you walk are bound to be more than what the figure says, except in those rare cases where the street forms a straight line.

Anyway, let’s assume a very rough error rate of 20 km to end up to a convenient total length of 800 km. To put that in perspective, Sodankylä, the venue for the legendary annual Midnight Sun Film Festival in Finnish Lapland, is about 800 km North from Helsinki. Given a modest rate of 5 km walking per day, starting about now, I’d reach Sodankylä in time for the next festival. In Helsinki, were I to walk one or two streets every weekend, the project of Walking Them All would be finished in 15 years.

What does Helsinki look like, street-wise?

The opening state of the interactive web app hkistreets that marks the first and last address on every street, shows how the bulk of them is spread along the North-South axis. Helsinki sits on a tip of a peninsula with a slight bending towards right. This North-Eastern area is fairly new. In 2009, a slice of Sipoo was annexed in Helsinki.

Notice the few markers above the sea. Helsinki occupies 315 islands, and from these, a couple have got an address which reveals that there’s something else on the island than just summer cottages, if anything. Rysäkari for example, the most Southern island, is a former military base, and a future tourist attraction (news in Finnish).

Most of the streets of Helsinki can be walked in 5 minutes if you are in a hurry; over 90% are under 500 m (1640 feet). 6% have only one address which means that they are an obscure lot. Either the street do is short or in fact it is some other place of interest (to be cleaned) like the centrally located square Paasikivenaukio 2 with the 40 ton granite statue of the former President of Finland Juho Kusti Paasikivi. 2% are under 1 km, and 0.9% between 1 and 3 km.

Only two streets in Helsinki are longer than 3 km. Mannerheimintie is a giant, almost 14 km, and known to all, whereas Jollaksentie (5 km) in South-East is a less visited suburban stretch. At the end of it, you are close to the last big unbuilt island of Helsinki, Villinki.

Google Street View does not cover all coordinates in Helsinki, as neat as it would be – sometimes because my coordinates are too far from streets – so popup links will often hit a black screen. Technically, I guess I could scrape all targets beforehand and only serve those that have something to look at, but Google TOS might not like it so I’ll let that idea be.

The R source code is available at Github.