Talk:WikiProject Greece/National Road Network

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i think the main page has become too dense and needs some modifications to be more readable (someone needs to scroll too far to find the list of roads) --JayCBR (talk) 11:35, 30 April 2017 (UTC)

Issues and responses (main page)

The extremely limited application of National and Provincial Road numbers on road signs means that mapping them is extremely difficult, and has been a source of major confusion and uncertainty to two major national-level mappers, ika-chan! and JayCBR. Unlike the ongoing financial issues in Greece, OpenStreetMap has been able to address nearly all of these problems.

Inconsistent numbering


The National Highway numbering system sees regular use on many road maps and legislation. However, they rarely appear on actual road signs, and in some cases they show the wrong National Road number.

In 1998, the National Roads of Greece Register, from the National Statistical Service of Greece (ΕΣΥΕ/NSSG, replaced by the Hellenic Statistical Authority (ELSTAT) in 2010) complicated the situation further (especially with suffixes),[1] with the 1998 register numbers and suffixes (e.g. ΕΟ9γ and ΕΟ65β) being widely ignored, even by the ΟΚΧΕ.

Thus, the consensus in the Greek road community regarding the suffixes is that ΕΟ1α, ΕΟ8α, ΕΟ9α, ΕΟ16α and ΕΟ34α are the only official numbers — all of which dated before 1998 register.[2][3]


For the numbers alone, the way in which OpenStreetMap maps the National Highway numbers is not a major issue since the legislation already shows how to do it (e.g. Ε.Ο. 1, Ε.Ο. 2): however, OpenStreetMap omits the full stops and spaces for sake of brevity (e.g. ΕΟ1, ΕΟ2). Nevertheless, the way in which legislation shows the road numbers has become the basis for how OpenStreetMap maps Provincial Road numbers on ways (e.g. ΕΠ1, ΕΠ2, albeit using reg_ref=* instead of ref=*).

Vague or fragmented routing


With the extremely limited application of National and Provincial Road numbers on road signs, the only clue for the routing of National Highways in the early days of OpenStreetMap was the quality of the roads between the destinations that ΦΕΚ A 47/1956 and ΦΕΚ B 319/1963 (and later revisions) defined.

The former Hellenic Mapping and Cadastral Organization (ΟΚΧΕ/HEMCO, taken over by the Ministry of Environment & Energy in 2013) has a Database of National and Provincial Roads. However, the ΟΚΧΕ map is not only out of date, but it also has many gaps and ambiguities, and inappropriately shows all service roads as part of the secondary National Road network.

For OpenStreetMap, these errors lead to severe fragmentation because the National Highways are now divided into the primary, secondary or tertiary network, and that the community has agreed that each subcategory warrants a different highway type (currently highway=trunk, primary and secondary respectively).[4]


Thus, while the ΟΚΧΕ map is a helpful guide, mappers must use judgement for the sake of maintaining network integrity and take new or realigned roads in account.[5] For example:

In order to reduce confusion and uncertainty, mappers are strongly advised to use note:highway highlight ways that are affected by errors or unrealised sections in legislation or the ΟΚΧΕ map: note:highway would have notes such as:

“ΟΚΧΕ shows this as ΠΕΟ1, but this would have left an unacceptable gap between ΕΟ8 and ΕΟ54.”


“ΕΟ1 shown as current, because ΟΚΧΕ shows it as a extant national road, and also due to the extent of deviation from the Α1 motorway.”

In some case where toll motorways have replaced National Roads in situ (e.g. the Α1 replacing many parts of the ΕΟ1 or ΕΟ1α), we can invoke ΦΕΚ Β 30/1996 (page 227) to map the most appropriate service roads around the tolls as part of the secondary or tertiary National Road network (highway=primary or secondary respectively, depending on the extent of the deviation). For all other service roads, use tertiary or lower instead.

Occasionally, there have be issues with the physical condition of a section of National Road for wheeled vehicles. With surface and smoothness, as well as lanes, width, etc., it is possible to relay the physical condition without changing the classification in nearly all cases. Again, mappers should use note:highway to highlight cases where the physical condition is so bad that no wheeled vehicle can safely use it.

Multiple names


One National Highway can have multiple names. For example, the following non-street names describe the ΕΟ8 (in order of length):

  • Εθνική Οδός 8
  • Εθνική Οδός Αθηνών - Πατρών
  • Εθνική Οδός Αθηνών - Κορίνθου
  • Εθνική Οδός Κορίνθου - Πατρών
  • Εθνική Οδός Αθηνών - Κορίνθου - Πατρών
  • Εθνική Οδός Αθηνών - Κορίνθου - Κιάτου - Δερβενίου - Αιγίου - Ρίου - Πατρών (if we have every destination that ΦΕΚ B 319/1963 defined!)


The resolution for the example above is that:

  • The ways along the route of the ΕΟ8 will use either name=<local street name> or name=Αθήνα - Κόρινθος, with the signed street name having unquestionable dominance.
  • The relation for the ΕΟ8 (relation 5863927) will use name=Εθνική Οδός 8 (Αθήνα - Πάτρα) and official_name=Αθήνα - Κόρινθος - Κιάτο - Δερβενί - Αίγιο - Ρίο - Πάτρα.

Owing to the international nature of OpenStreetMap, the names are repeated in English, French. OpenStreetMap advises against transliterating, but such practice remains common even outside Greece, because many of the widely used renderers ironically rely on int_name=* for official transliterations.

  1. National Roads of Greece Register, 1998
  2. Re: (GR) Greece - road infrastructure • Ελληνικοί Αυτοκινητόδρομοι, 2017
  3. Re: (GR) Greece - road infrastructure • Ελληνικοί Αυτοκινητόδρομοι, 2017
  4. In Greece, highway=tertiary is reserved for unclassified roads that connect towns, villages and points of interest to each other, or to the classified road network. Both unclassified and residential are for local roads (depending on landuse), while track is for rural use.
  5. In 2016, for example, a large section of ΕΟ39 in Laconia was re-routed to avoid Sparta as part of a growing trend of many European trunk roads bypassing small towns.