# Graph representation of NUTS-3 regions to determine adjacency

I need a graph representation of NUTS-3 regions in the European Union, which can answer the question whether a certain region is neighbor of another region.

Dataset available?

I have looked at the data available from geovocab and from EuroGeographics but I cannot find discrete adjacency information there. Is there a dataset or available transformation routine out there with this information?

Proposal for an algorithm

Otherwise I would apply the following algorithm to get this graph:

1. Get NUTS-3 data with named city
2. Find lat/lon of city and create the nodes of the graph
3. Determine pairwise distances between all nodes
4. Determine pairwise angle between all nodes
5. Given the polar coordinates from step 3/4, find the nearest neighbors in every direction
6. Create edges between these nodes

Do you have comments or improvements on this algorithm?

• You need to define adjacency, is it an exact touch or is across a river or inlet sufficient? For the algorithm q you should ask on GIS.SE Commented Dec 21, 2016 at 19:45
• The NUTS areas do not rely on physical things in the surface. They are just administrative areas and they all have one or more direct neighbors unless they are isolated, but I am not sure this case exists on level 3. Commented Dec 22, 2016 at 7:04

## 1 Answer

Based on the NUTS-3 Boundaries in Eurostat and some GeoTools code I generated this list for you. Where the first column is the NUTS_ID of the zone and the list in [] is the list of neighbours, which may be empty.

``````AT111:[AT112, AT113, AT122, HU221, HU222]
AT112:[AT111, AT122, AT127, HU221, SK010]
AT113:[AT111, AT122, AT224, HU222, SI011]
AT121:[AT122, AT123, AT124, AT222, AT223, AT312, AT313, AT314]
AT122:[AT111, AT112, AT113, AT121, AT123, AT127, AT223, AT224]
AT123:[AT121, AT122, AT124, AT126, AT127]
AT124:[AT121, AT123, AT125, AT126, AT313, CZ031, CZ064]
AT125:[AT124, AT126, CZ064, SK010, SK021]
``````