[HOT] Damage evaluation tagging schema

Pierre Béland pierzenh at yahoo.fr
Fri Jan 23 01:33:19 UTC 2015


>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
damage:revision:building:haiyan=collapsed

Level===========================
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




Example 

    <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' />


Pierre 
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