[Talk-GB] RFC: Solar panel mapping in the UK

Russ Garrett russ at garrett.co.uk
Thu Apr 4 15:09:56 UTC 2019

Hi Dave,

On Thu, 4 Apr 2019 at 14:11, Dave F via Talk-GB
<talk-gb at openstreetmap.org> wrote:
> This would be a great project, however I think there's some confusion in
> the tagging which requires agreeing/clarifying.

Solar farms should have a power=plant covering the whole perimeter as
an area or multipolygon. I agree with you that relations shouldn't be
used because they're unnecessary. The output of the farm should be the
"plant:output:power=" tag on that object.

The use of power=plant for this was enshrined in the approved Power
Generation Refinement tagging proposal back in 2013 [1]. It also makes
sense by analogy to wind farms (where we do use power=plant on

I would argue landuse=industrial is not appropriate in this case,
notwithstanding what the wiki says, and perhaps landuse=grass is
appropriate here.

As a rule of thumb, 1 MW is probably a good initial threshold to use
when deciding whether to use the power=plant tag for solar, if only to
focus our tagging energy on larger plants to start with.

The power=generator tag should represent the arrays of panels as
closely as you can be bothered. I generally tag contiguous blocks of
panels as one power=generator, rather than every individual row. With
OpenInfraMap I'm now starting to estimate the output of solar
generators by their area, so I have a preference towards seeing them
tagged as closely as possible. However, I have little patience for
micro-mapping so I feel like each block of panels is a good


[1] https://wiki.openstreetmap.org/wiki/Proposed_features/Power_generation_refinement

Russ Garrett
russ at garrett.co.uk

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