[HOT] Damage evaluation tagging schema

Pierre Béland pierzenh at yahoo.fr
Fri Jan 23 03:30:20 UTC 2015

Hi Mark
I agree, we have to consider also aspects like how easy to extract for an event. For Haiyan, we had a specific tag. But what, if it would have be necessary to add tags recently for Hagupit?
About SQL queries, are-they any efficient way (time related) to sayselect objects where key contains "haiyan" ?

      De : Markware Software Services <markwaresoftware at gmail.com>
 À : Pierre Béland <pierzenh at yahoo.fr> 
Cc : HOT Openstreetmap <hot at openstreetmap.org>; S Volk <svolk2 at hotmail.com> 
 Envoyé le : Jeudi 22 janvier 2015 21h21
 Objet : Re: [HOT] Damage evaluation tagging schema
Hi Pierre
Excellent Thoughts. Interestingly, I am working on a 3D rendering of buildings project now, and was planning on extending this to HOT's work when done with the commercial project.
Having everything in one tag "k=" as you propose helps the query and rendering scenario a lot. The only downside from a database perspective would be if you ever needed to query for data within the key data itself. This would be very slow. 

For Example:  if someone wanted to display all Haiyan related data the query would be something like WHERE k is Not Null and lower(k) LIKE "haiyan%" which would trigger a sequential Pattern Match Scan. k would need to be indexed, which would help somewhat.
One option would be to consider a couple of specific tags to help any searches on columns that can be indexed, like 
hot:damage=type of damage string (as per your proposal)hot:crisis=Haiyan
This would allow rapid extraction of all Haiyan related data using indexes with a query like WHERE hot:damage is not null and lower(hot:crisis)="haiyan";

Also, consider adding "hot:" to the tag as this makes it very clear where the data source is.
Just some thoughts for you to consider

Also, Do you have a summary of what tagging schemes were actually used during Haiyan, I seem to recall building=damaged, or building=yes, damage=*

Mark Cupitt
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On Fri, Jan 23, 2015 at 9:33 AM, Pierre Béland <pierzenh at yahoo.fr> wrote:

>From the discusssion about mapping North of Nigeria, I open a distinct thread about the Damage evaluation discussion about the more technical aspects related to Damage evaluation and tagging schema.

This wiki page describes the schema used for the Haiyan typhoon.http://wiki.openstreetmap.org/wiki/Damaged_buildings_crisis_mapping

As we discussed at the beginning of the Haiyan activation, while establishing a temporary schema, this was be revised later to not affect tags such as building or highway.  Distinct tags should be added to reflect damages, road obstacles, debris or any other damage related objects. Any modifications will also have to be reflected in the humanitarian style to have the capacity to show damages on the map as we did for Haiyan.

While the BaseMap is our priority, there might be some emergencies where we are asked to collaborate to Damage evaluation. For each of these events, we have to discuss among us and carefully evaluate if it is pertinent to do so. 

Methodology is an other aspect. As it was discussed after Haiyan, there are limits to what can be done with Imagery. We cannot have the same classification / hierarchy of damages from an aerial evaluation (often poor quality images in the context of climate related disasters) and field evaluation.
While we might decide to not do these evaluations, it is important to establish a good tagging schema and be ready for our next such action.
It dont think that this is a solution to have two attributes on the same key like building="commercial; damaged". It would be more difficult to query and this would breaks the rules for the map renderer styles. 
There are also discussions about adding permanently tags to the database and later not revising it.  More then a year after Haiyan, there are still a lot of damage related tags.  I have started to analyze how to revise this. But not yet processed.
There are various aspects to consider. 
- Use a map style to render damages (like the Humanitarian style for Haiyan)- Distinct methodology for aerial views or survey evaluations  ->  Specific role + limits of aerial views vs structure damages- Evaluation vs Revision (either imagery or field survey)

The objects to evaluate can vary from one disaster to the other.  From the Haiyan experience, below I present proposals for tagging schema specific to an event. In this example, in the context of the Haiyan typhoon damages. Tnis same logic could be extended to  objects affected by other type of disasters.  

There are also various evaluation actions and status of actions  that sometimes need to be registered.- Type of action: aerial evaluation and revision, field evaluation and revision- Status of the revision : cloud coverage limited the evaluation.
The OSM key could be structured with various levels separated by semi-colons (ie damage:evaluation:building:haiyan).
If both evaluation and revision key where present, the style renderer rules could give a priority of revision over evaluation tags.

damage:evaluation:building:haiyan=no_damagewould supersede effect of

1 damage2. evaluation, revision
3. type, building, barrier, debris4. event (ie. haiyan)

key                                                         value--------------------------------------------------------------------------------
damage:evaluation:type:haiyan         imagery, surveydamage:revision:type:haiyan             imagery, survey
damage:evaluation:building:haiyan   damaged, collapsed, no
damage:revision:building:haiyan       damage, collapsed, no
Highway Barrier on nodes
damage:evaluation:barrier:haiyan     debris, no
damage:revision:barrier:haiyan         debris, no

Impassable highway sections
damage:evaluation:status:haiyan      impassable, passable

Area Debris

damage:evaluation:landuse:haiyan    brownfield, no
damage:revision:landuse:haiyan        brownfield, no


    <tag k='building' v='yes' />
    <tag k='damage:evaluation:type:haiyan' v='imagery' />    <tag k='damage:evaluation:building:haiyan' v='damaged' />
    <tag k='damage:revision:type:haiyan' v='imagery' />    <tag k='damage:revision:building:haiyan' v='collapsed' />
    <tag k='damage:revision:type:haiyan' v='survey' />    <tag k='damage:revision:building:haiyan' v='collapsed' />

    <tag k='highway' v='trunk' />    <tag k='damage:evaluation:haiyan' v='yes' />    <tag k='damage:revision:haiyan' v='yes' />    <tag k='damage:evaluation:barrier:haiyan' v='debris' />
    <tag k='damage:evaluation:type' v='imagery' />
    <tag k='damage:revision:debris:haiyan' v='no' />
    <tag k='damage:revision:type' v='survey' />
    <tag k=damage:haiyan' v='yes' />


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