Hej Sabrina,<div><br></div><div>I don't have imagery for you but if you're interested I am happy to share you my thoughts on some of the quality issues related to VTC-based damage assessment quality.</div><div><br>
</div><div>This is based on my experience living in Haiti since September 2010, mapping it since right after the quake (as a more or less newbie OpenStreetMapper, now the most active mapper _on_ the island), but perhaps most importantly based on my experience with evaluating hundreds and hundreds of building=collapsed, etc earth quake damage objects in the OSM database over the time I've done mapping here -- and ending up deleting practically all of them partly because they (without any additional information such as image links, names of collapsed buildings or other building / POI-in-the-building details) are no longer useful in OSM in general but to good extent because of the problems in data.</div>
<div><br></div><div>Very clearly The Biggest single problem that I found in the building damage assessment data in Haiti (which was partly traced to the db by OSM-volunteers, mostly imported -- iirc) was that many who had done the assessment had clearly never been to Haiti nor any other similar country. .. I say this because I saw countless buildings that -- for someone who has been here / a developing country -- were very clearly not collapsed but marked as such simply because they were (and many still are) under construction and missing the roof -- possibly only from the top floor. And as in many developing countries this is completely normal and quite common.</div>
<div>The other problem of especially the imported collapsed buildings data for keeping in the OSM longer was that since it was nodes only and very dense at some points it was practically useless combined with the various absolute and relational inaccuracies that exist in geo data (starting from misalignments/offsets of various imagery, inaccuracies of various data added over time, etc). So, I've nuked them from the OSM database. ... Which also means that if you want to asses the damage assessment data that once was in OSM you need to look at a data snapshot from, say, from fall of 2010.</div>
<div><br></div><div>Now, there's something to think about -- or perhaps look into a bit more first -- for someone who's interested related to this.</div><div>I don't know if many people on this list have read/heard but there was a study/evaluation done on the Feb 2010 quake damage perhaps a year ago or so. In short it concluded that there could not have been more than about 80,000 casualties in the quake (in stead of the official number of closer to 300,000). .. I haven't digged into this more but I know one of the people who were part of conducting the study who's a solid guy and can ask for the report / put anyone who might be interested in contact with him.</div>
<div>The study was obviously not accepted broadly (as the official numbers still stand "unchallenged") and there are reasons not to flaunt it regardless of how right the study would be. And some of those reasons might be good. </div>
<div>But for the sake of an academic discussion for this case/topic-at-hand I am wondering if it _could_ be possible that _<i>should</i> the official casualty numbers of the quake be bloated_: </div><div>What might the reason_s_ / enabling factor_s_ of that be? </div>
<div>.. And more so, based on experience with the issues with the quick building damage assessment data: </div><div>Could the bad quality (and bloated) building damage assessment data have given an impression or base for larger-than-true casualties?</div>
<div>Now, if I remember right the casualty numbers came out so fast in the beginning that _it seems_ (to someone like me who doesn't know better) that nobody had data to back it up and I think that not even the new-imagery-based building damage assessment data was out then so (if this was the case) one can draw one's own conclusions from that. </div>
<div><br></div><div>But in any case: it's a pretty clear fact to me that there were some real issues with some of the building damage assessment data and that should give food for thought in preparing for similar future cases. .. You might want to look at / do some comparisons of different source of damage data. .. And you should most certainly also (try to) compare your evaluations with the official on-the-ground evaluations of MTPTC(/UNOPS).</div>
<div><br></div><div>Cheers from Haiti,</div><div>-Jaakko</div><div><a href="http://osm.org/user/jaakkoh">http://osm.org/user/jaakkoh</a></div><div><br clear="all"><div>--</div><div><a href="mailto:jaakko@helleranta.com" target="_blank">jaakko@helleranta.com</a> * Skype: jhelleranta * Mobile: +509-37-269154 * <a href="http://go.hel.cc/MyProfile" target="_blank">http://go.hel.cc/MyProfile</a></div>
<br><div class="gmail_quote">On Mon, Jul 2, 2012 at 5:06 PM, Sabrina Grimsrud <span dir="ltr"><<a href="mailto:sabrina.grimsrud@geodata.no" target="_blank">sabrina.grimsrud@geodata.no</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div lang="NO-BOK" link="blue" vlink="purple"><div><p class="MsoNormal"><span lang="EN-US">Dear Humanitarian OSM team, <u></u><u></u></span></p><p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p><p class="MsoNormal">
<span lang="EN-US">I am an MSC student writing my thesis about the quality of volunteered geographic information in disasters and using Haiti as an example. <u></u><u></u></span></p><p class="MsoNormal"><span lang="EN-US">I would like to try to re-create the disaster mapping but I am having difficulties finding pre-earthquake imagery to compare to: there are a lot of links for imagery that can be used in one of the OSM editors and images for individual damaged buildings, but I haven’t found anything free that I can download and use in ArcGIS. I am looking for imagery of Port-au-Prince before the earthquake happened.<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US">Do you have any suggestions? Thanks in advance for your help!<u></u><u></u></span></p><p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p><p class="MsoNormal"><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1f497d">Kind regards, <u></u><u></u></span></p>
<p class="MsoNormal"><b><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1f497d"><u></u> <u></u></span></b></p><p class="MsoNormal"><b><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1f497d">Sabrina Grimsrud</span></b><span lang="EN-US" style="font-size:10.0pt;font-family:"Arial","sans-serif";color:#1f497d"><br>
MSc GIMA student </span><span lang="EN-US"><u></u><u></u></span></p><p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p></div></div><br>_______________________________________________<br>
HOT mailing list<br>
<a href="mailto:HOT@openstreetmap.org">HOT@openstreetmap.org</a><br>
<a href="http://lists.openstreetmap.org/listinfo/hot" target="_blank">http://lists.openstreetmap.org/listinfo/hot</a><br>
<br></blockquote></div><br></div>