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</div><div>Hello all, </div><div><br></div><div>Ruben led out MapBox's analysis, the results of which you can see in his previous message. While these maps do a fairly good job of identifying areas that have and have not been edited, we're not entirely satisfied with their ability to identify where TIGER ways just don't represent the actual geographic location of roads on the ground. </div><div><br></div><div>Another thought we've had is to do some flavor of comparative analysis between 2007 TIGER and 2012 TIGER. This might me clipping 2007 to the 2012 dataset to identify where roads do not overlap (and then perhaps some raster/binning to identify problem areas). Just wondering what other ideas might be out there - hit me up with your ideas. </div><div><br></div><div>thanks!</div>
<div><div><br></div><div>-- </div><div>ian villeda</div><div>mapbox | developmentseed</div><div><a href="https://twitter.com/ian_villeda">https://twitter.com/ian_villeda</a></div><div><br></div></div>
<p style="color: #A0A0A8;">On Wednesday, December 19, 2012 at 8:39 PM, Ruben Lopez Mendoza wrote:</p>
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<span><div><div><div dir="ltr"><p style="margin-right:0px;margin-bottom:15px;margin-left:0px;color:rgb(0,0,0);font-family:Helvetica,arial,freesans,clean,sans-serif;font-size:14px;line-height:22px;margin-top:0px!important">We've worked out some kinks of our first attempt to identify TIGER deserts, and produced maps a couple maps along the way.</p>
<p style="margin:15px 0px;color:rgb(0,0,0);font-family:Helvetica,arial,freesans,clean,sans-serif;font-size:14px;line-height:22px">Average version of all highway =* ways <a href="https://tiles.mapbox.com/ruben/map/map-badetj1b#7.00/37.927/-78.466" style="color:rgb(65,131,196);text-decoration:initial">https://tiles.mapbox.com/ruben/map/map-badetj1b#7.00/37.927/-78.466</a></p>
<p style="margin:15px 0px;color:rgb(0,0,0);font-family:Helvetica,arial,freesans,clean,sans-serif;font-size:14px;line-height:22px">Percent version 1, highwahy=* ways per gridcell <a href="http://tiles.mapbox.com/ruben/map/map-4t3notfw#9.00/37.2805/-78.2528" style="color:rgb(65,131,196);text-decoration:initial">http://tiles.mapbox.com/ruben/map/map-4t3notfw#9.00/37.2805/-78.2528</a></p>
<p style="margin:15px 0px;color:rgb(0,0,0);font-family:Helvetica,arial,freesans,clean,sans-serif;font-size:14px;line-height:22px">Comparison: <a href="http://bl.ocks.org/d/ff2607349777ddee9181/" style="color:rgb(65,131,196);text-decoration:initial">http://bl.ocks.org/d/ff2607349777ddee9181/</a></p>
<p style="margin:15px 0px;color:rgb(0,0,0);font-family:Helvetica,arial,freesans,clean,sans-serif;font-size:14px;line-height:22px">As input we used a database of all highway=* ways and their version number created using Osmosis and a grid generated from a Natural Earth shapefile.</p>
<p style="margin:15px 0px;color:rgb(0,0,0);font-family:Helvetica,arial,freesans,clean,sans-serif;font-size:14px;line-height:22px">I created a postgres function that populates a new table called tiger_grid. For each cell, we calculated each of the following:</p>
<ul style="margin:15px 0px;padding:0px 0px 0px 30px;color:rgb(0,0,0);font-family:Helvetica,arial,freesans,clean,sans-serif;font-size:14px;line-height:22px"><li>amount_version1</li><li>amount version2</li><li>percentage _version1</li>
<li>percentage version2</li><li>average_version</li></ul><p style="margin:15px 0px;color:rgb(0,0,0);font-family:Helvetica,arial,freesans,clean,sans-serif;font-size:14px;line-height:22px">I've captured all of this work - the postgres functions, shapefiles, and tilemill projects in the a repo here:<a href="https://github.com/Rub21/tiger-deserts" style="color:rgb(65,131,196);text-decoration:initial">https://github.com/Rub21/tiger-deserts</a></p>
<h3 style="margin:20px 0px 10px;padding:0px;font-size:18px;color:rgb(0,0,0);font-family:Helvetica,arial,freesans,clean,sans-serif">next steps</h3><p style="margin:0px 0px 15px;color:rgb(0,0,0);font-family:Helvetica,arial,freesans,clean,sans-serif;font-size:14px;line-height:22px">
A few obvious steps stand out, including rendering a national version of these maps. I'd also love to figure out whether it makes sense to join forces with Mike Migurski's Green Means Go map.</p><p style="margin-top:15px;margin-right:0px;margin-left:0px;color:rgb(0,0,0);font-family:Helvetica,arial,freesans,clean,sans-serif;font-size:14px;line-height:22px;margin-bottom:0px!important">
It'd also be interesting to use a smarter Osmosis command (and the full history file) to limit the input data to just those ways created by the 3 primary user accounts associated with the TIGER import:<a href="https://github.com/MapQuest/TIGER-Edited-map/blob/master/inc/layer-tiger.xml.inc#L45" style="color:rgb(65,131,196);text-decoration:initial">https://github.com/MapQuest/TIGER-Edited-map/blob/master/inc/layer-tiger.xml.inc#L45</a> (h/t Migurski)</p>
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