[HOT] Waterway Tagging

Will Skora skorasaurus at gmail.com
Mon Jan 26 02:38:46 UTC 2015


First of all, thanks for the civil discussion and sharing your thoughts.
Here's some thoughts and reflections.

As Ralph noted, there's two issues here:
1] the rendering (how to display) waterways that are do not always flow;

2] and how to classify/tag them.

I'll write some background on how the HOT rendering works and my experience
classifying them as I try to remember all of this and look at my notes:

The HOT Tagging Presets were the basis for HOT's Web Map Rendering and JOSM
style and to describe the features encountered in HOT contexts and
developing areas whose features that were often not represented in the
'default' OSM map styling. The HOT tagging preset does not include any
intermittent or seasonal keys and the HOT (aka: HDM) tags were revised in
Spring 2013 during the Haiti mission. (

(also found at: https://github.com/hotosm/presets and

I do not have any reason to believe that this omission was intentional and
as a participant in the later half of the Haiti Mission, there were efforts
to include the seasonal and intermittent tags into all three
https://github.com/hotosm/HDM-CartoCSS/issues/105 and

Why weren't the tags added to the preset? I can only explain my reasons
which is simply that my paid time with HOT was over once the mission was
over in June '13 and there were simply not enough didn't have enough time
to continue working on it and had other priorities including the map

With the HDM map rendering, we had only accepted the values of 'yes' for
the seasonal and intermittent keys because at the time, over 90% of each
values were 'yes' according to taginfo. As of June 2013, most (90%) of the
use of intermittent was in the USA from an old import.
(I calculated this from an instance of taginfo that included only the USA.
Unfortunately, this instance of taginfo is no longer available.) That still
leaves with about 60,000 of intermittent= .

I'll admit that until this conversation, I didn't know the term wadi had
existed or that the tag existed.

Regardless of the discussion of tagging mailing list (which is actually
coming to a consensus that wadi should be deprecated), I don't know how
waterway=wadi would fit in since as I understand the tag, waterway=river,
stream, or ditch,
along with intermittent=yes or seasonal=yes would be more appropriate.

If you'd like to add the HDM Preset, remember that there isn't a particular
# of objects that the tag should be used but that whatever tag that you're
proposing isn't covered by another tag, and write a bit about how you and
your community use it in your mapping on the github page and on the HOT
mailing list. If the tag is used a specific project, even better, that
would get more support on the HOT mailing list.

When I trace from satellite imagery and see a waterway without any water in
it, I use intermittent=yes or seasonal=yes since there's no way to
determine which is more appropriate to use without further information
(like a on the ground survey).

If you have any ideas or proposals for other intermittent and seasonal
values besides yes, share them. I would believe those participating in the
Amazonia. I do see Ivan had shared his proposal - thank you - but I don't
understand its advantages of the current tagging situation.

If anyone would like to translate this to other mailing lists; you're
encouraged to do so.

Warm Regards,
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