Our own derivation: There is
no usable tree register here — see below. The tree
locations therefore come from the official normalised surface model
nDOM50 of Geobasis NRW (dl-de/zero-2.0), flown between 2022 and
2024, mostly in late May with the trees in leaf, 50 cm grid spacing.
The method looks for local height maxima in the 5 to 45 m band; hits on
official ALKIS building footprints and everything outside the city area
are discarded.
Limit: Every crown from about five metres
up is captured — including on private land and in forests,
unlike a register. Younger plantings below that are missing, as are
species and planting year. The crown diameter is estimated from the
height, not measured. The computation deliberately runs on a 1 m grid
rather than the available 50 cm: on the finer grid the method finds
every fork of a branch in a closed canopy as a separate tree and returns
roughly six times the number.
A single GeoPackage from the state holds both land use and building footprints. The use category is given there as German plain text, not as an AAA key as in Bavaria. Heterogeneous catch-all categories are deliberately not coloured in, rather than being assigned a colour that would be wrong. opengeodata.nrw.de
From the same package, as grey context beneath the other
layers. Canopies, carports, passageways and projecting parts of upper
storeys are filtered out.
Limit: The storey-count column exists in
the schema but is empty throughout the simplified state delivery. This
source does not support any statement about shading from building
heights; the layer therefore remains pure context.
Better than the Bavarian analyses in three respects, and all three change what this map is allowed to say: 25 m instead of 100 m grid spacing, fine enough for individual streets; two scenarios (a typical and an extreme summer day) instead of one; and a genuine night-time air temperature as the quantity measured, instead of a class scale. State Office for Nature, Environment and Climate NRW
City boundary, 849 gathering places, roadside parking and the address search via Nominatim. No official parking survey exists for this city; the number of spaces is estimated from OSM parking strips and is therefore a lower bound. openstreetmap.org
Because absolute PET values are available, the five classes are cut at the thresholds of VDI guideline 3787 (23 / 29 / 35 / 41 °C) instead of, as usual, by quantiles of the respective city's distribution. „Strong heat stress“ here therefore literally means „PET of 35 °C and above“ and not „the hottest fifth of this city“. Only that makes this layer comparable between cities — exactly the property whose absence was the reason to drop the quantile layer entirely for the Bavarian municipalities. Result: 60.3 % of the city area at 35 °C and above, 11.7 % at 41 °C and above.
The night layer uses the modelled air temperature at 4 am, cut at 16 / 18 / 20 / 22 °C. The 20 °C line deliberately falls on a class boundary, so that „class 4 or 5“ matches the German Weather Service definition of a tropical night exactly. The difference between the scenarios is drastic: in a typical summer night 0.0 % of the area reaches tropical night level, in an extreme night 64.1 %, with peaks up to 23.9 °C. The map layer therefore shows the extreme night — a map of the typical night would be a single colour.
Crown areas are estimated from tree height (diameter = 0.55 × height, capped at 14 m) — the same relationship as in Ludwigshafen and Mannheim, so the figures stay comparable between cities. Search areas are connected stretches of street space of
150 m² or more without crown cover and without a tree closer than
eight metres — 1,031 across the city.
The heat indicator (24.6 % of street area at 35 °C and
above without a tree within 17 m) was recomputed with an
independent script on a 5 m grid. The radius corridor of
15–20 m yields 17.8 to 28.4 %: the statement does not
hinge on the choice of radius.
Unlike Bergisch Gladbach or Cologne, Meerbusch keeps
— as far as is publicly visible — no tree register of its
own. Checked on 1 August 2026: the municipal geoportal lists only
land-use plans, standard land values, heavy-rain hazard maps, a solar
potential register and historical maps. The shared open data portal of
the Rhein-Kreis Neuss district holds 40 datasets on Meerbusch —
cycle routes, playgrounds, cemeteries and the like — but not one
on trees. Neighbouring Neuss, by contrast, publishes
„Baumbestand“ (tree stock) and „Baumkronen“
(tree crowns) in that same portal explicitly under CC0; a tree register
would therefore have a place in this portal if one existed.
Hence the derivation from the surface model. Should it turn out that
the city does keep a register internally, a request following the
Bergisch Gladbach pattern would be the next step.
The simplified ALKIS delivery carries no storey counts. A real shading computation — which tree stands in a building's shadow at what time, and where only a tree can help — would require the unsimplified delivery or the LoD2 model.
The search area analysis works exclusively on the designated street traffic area (3.74 km²). Private plots, yards and commercial sites are left unassessed, although shade may be missing there too. Whether a tree can actually stand in a given search area depends on underground utilities, emergency access routes, sightlines and parking spaces that would be lost — all unchecked.