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View Full Version : Wide-line Roads for GR Products Downloadable as Placefiles



Scott Lincoln
06-20-2009, 01:05 PM
I posted this thread on the GR owners forum and thought it might be of interest here. The placefiles mentioned can be downloaded and added to GR products.

OpenStreetMap Project Overview
I wanted to bring everyone's attention to something new I have been working on that involves the OpenStreetMap (OSM) project - wide-line road placefiles. Just a reminder that OSM is a type of Volunteered Geographic Information (VGI) that contains global road, trail, water, locations, and boundary features freely editable by registered users, just like Wikipedia. To view the interactive maps rendered weekly from this database in a manner similar to Google Maps, visit the OSM website: http://www.openstreetmap.org


Central US Roads Shapefile
That other roads project that I have been working on to make radar site-specific shapefiles for the central US requires the creation of one massive, region-wide shapefile of all of the roads before it can begin clipping them to the 150mi ranges around radar sites. Using GIS, I can select only the roads from this file that I want (example: only interstates), and then create new shapefiles from that subset. I have done this for interstates, expressways, and federal highways around Iowa. Each of these subsets can then be converted from the shapefile format to another format using a conversion tool.


Converting to Placefiles
Using the conversion tool mentioned, each of the shapefiles for major road types was converted into a text file full of points for the lines. These text files end up being many megabytes in size. They require just a little bit of tweaking from a program that can handle large text files (example: MS Word), and after that they can be converted into placefiles. I wrote a script that goes through this list of points, and can figure out which points belong to which line. As it does this, it writes a text file that is formatted as a placefile for GR, using the threshold, width, and color specifications that you indicate. These output files are also quite large, and do slow down GR a bit. Despite the drawbacks, I think they turned out looking quite nice, especially for people that use the program in presentation settings, or in the broadcast media. Some example screenshots from the southeast Minnesota supercell outbreak a few days ago:

http://www.meteor.iastate.edu/~slincoln/GRS/Wide_Roads_Screenshot_1.png (http://www.meteor.iastate.edu/%7Eslincoln/GRS/Wide_Roads_Screenshot_1.png)
http://www.meteor.iastate.edu/~slincoln/GRS/Wide_Roads_Screenshot_2.png (http://www.meteor.iastate.edu/%7Eslincoln/GRS/Wide_Roads_Screenshot_2.png)


For People Editing Maps
Since this set of placefiles is based off of the OSM project just like the site-specific shapefiles, the quality of the data may not be the best at present. The good news is that people can become members of OpenStreeMap.org rather easily, learn how to use the editing tools, and fix most of the errors. Over time, this can become one of the most up-to-date, accurate road data sets that is freely available. I may also update these placefiles from time to time to keep up with major updates to OSM. For more information on editing the maps, visit my post on the site-specific shapefiles:

http://www.grlevelx.com/owners/viewtopic.php?f=15&t=5233

Also note that these placefiles refer to the road types differently than I do in my post above on the shapefiles. I renamed the road types to the general American names. Here is how they relate to the OSM project types:
Interstates = Motorways
Expressways = Trunk
Federal Highways = Primary


The Placefiles
Note: Although this required many hours of work to accomplish, I am going to make these files freely available, even to for-profit broadcast media. This is partly due to the license agreement to the open-source OSM data that makes it hard to require payment for data derived from their database. All I ask is that if a broadcast media entity or a company decides to use these, that I get sent an email or a private message so I have an idea who is getting use out of them. If more people are using them, especially groups that would require slightly better accuracy and updates, then I can take note of that.

http://www.meteor.iastate.edu/~slincoln/GRS/placefiles/Interstates_Placefile.txt (http://www.meteor.iastate.edu/%7Eslincoln/GRS/placefiles/Interstates_Placefile.txt) (7.5mb)
http://www.meteor.iastate.edu/~slincoln/GRS/placefiles/Expressways_Placefile.txt (http://www.meteor.iastate.edu/%7Eslincoln/GRS/placefiles/Expressways_Placefile.txt) (1.3mb)
http://www.meteor.iastate.edu/~slincoln/GRS/placefiles/Federal_Placefile.txt (http://www.meteor.iastate.edu/%7Eslincoln/GRS/placefiles/Federal_Placefile.txt) (7.7mb)