[Tagging] How might we best map emergency helicopter landing zones?

Greg Troxel gdt at lexort.com
Tue Nov 22 14:30:15 UTC 2016

>> On Nov 22, 2016 8:41 PM, "Blake Girardot" <bgirardot at gmail.com> wrote:
>>     I have worked with folks doing ground surveys of helicopter landing
>>     zones during emergency response.
>>     These are ground truthed locations, observed by active search and
>>     rescue helicopter pilots collecting the basic minimum critical ground
>>     survey items for an HLZ for their aircraft type.
>>     They collect the data and provide it in the public domain and I would
>>     like to map it.
>>     I think the vast majority of the items collected are already well
>>     supported in OSM, trees, light poles, ground type, area, grade,
>>     landuse.
>>     What would be the best way to map this data? Does it need its own
>>     namespace? Just map  regular OSM tagging and render the data myself
>>     custom?

For things that exist and are describable independent of caring about
helicopters, definitely you should use regular tags.  If there is some
feature of interest that doesn't have established tagging, you'll have
to invent it.  But choose tags so that anyone who cares about the thing
in question can be happy with, rather than only people looking at the
thing from the helicopter viewpoint.  (Easier said than done, I know.)

>>     I think issues of does the data belong in OSM are separate issues, I
>>     am just interested in how to map it and tag it well. I would be
>>     mapping nothing but ground truthed data that we already map every day,
>>     trees and light poles and ground type, landuse. It is publicly
>>     available data (CC0).

Sure, that's fine, but beware that you are perhaps verging on an import.

>>     Other data could and should be added specific to HLZ's so we will need
>>     to discuss any non traditional tags that I would like to see be used
>>     for the HLZs mapped.

Yes.  Here, I think it's mostly "this is a landing zone".

Tom Pfeifer <t.pfeifer at computer.org> writes:

> aeroway=helipad should be used only for built-up infrastructure, not
> for emergency places that have a different use normally.

It sounds like in the Korean mountain case that in my cases there are
on-ground markings at these sites.  That might be an intermediate case,
not a formal helipad but a pre-prepared and marked LZ.  I have also seen
these in the US, but not that often.  One case was in a big paved area
at the end of a road used to access a frequently-used steep trail.  It
was pretty obvious they were expecting trouble.

> An emergency landing place is nothing but a predefined clear space, it
> could be a soccer pitch or a big lawn in a park in normal situations.

Yes.  My town probably has a half dozen of these.  They are used for
medical evacuation helicopters (for people extricated from bad car
crashes who are iffy on making it, basically).

> There is already "emergency=landing_site" defined and used 1800 times
> that seems to fit the purpose of Blake exactly?
> https://wiki.openstreetmap.org/wiki/Tag:emergency%3Dlanding_site

That seems to fit, although the image has an H on the ground.

So perhaps we need

  emergency=landing_site means not a formal helipad that may or may not
  have some markings

  landing_site=unmarked means there is no on-ground markings for the
  pilot. (In these cases fire/police vehicles often make a circle to show
  the safe area and light it, because it's often dark and the
  trees/power lines cannot be seen.)

  landing_site=marked means there is a stone box or ring or a painted
  circle with an H, or something that is obviously intended to let the
  pilot know the surveyed-safe area to land

Since a helicopter can land anywhere big enough and unobstructed enough,
more or less, I think there's merit in having a tag (or defining
emergency=landing_site to be this) to denote places that are on a list
of preplaned emergency landing sites maintained by the relevant

The above comment will bring out the verifiabilty extremists.  My point
is that it would be nice for the local fire departments to be able to
use OSM, and that means having medflight LZs as well as water sources
(ponds with standpipes) etc.  It's possible to verify the LZs by talking
to the fire department people, and the reality that is being mapped is
not "this space is big enough for a helicopter" but "the fire department
has this place on their list of LZs".

So I would therefore add

  landing_site:source = official

when the site is known to be on the pre-planned list of some emergency
service, or something like that.
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