Tornado History Project - WOW

Tornado History Project - Great site for information

WOW - this was posted over on Eastern by forum user jlietz

Copy and paste


http://www.tornadohistoryproject.com/torna...amp;p=1&s=1

or in plain text for copy and paste operations:

www.tornadohistoryproject.com/tornadomap.php?yr=1998&mo=4&day=16&st=%25&fu=%25&co=&l=100&submit=Search&format=basic&p=1&s=1

Over the last year he has created a database of all tornadoes from 1950-2005 (using the NWS historical tornado file) that integrates with Google Maps. Any day or range of days can be plotted, but the link above will take you directly to April 16, 1998.

Looks like some of the paths might be slightly off...would be curious how he plotted them. The tornado days look right though - lot of information on the site.
 
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Joey Ketcham

Has anyone else checked the accuracy of the data on this site?

I just looked up April 19th, 2000, the day a tornado went through Parsons, KS. The track is wrong; it shows the tornado further south and completely missing Parson’s. The tornado entered Parsons on the southwest side, travelled northeast leaving a path of destruction before it exited on the northeast side of Parsons.


It’s a nice tool, maybe I’m being picky but if the path of tornadoes is wrong on there, then the data is inaccurate and not usable.
 
Dec 10, 2003
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I looked up a tornado in Toledo, OH in April 1981 (only Toledo tor in that month) and the placement is wrong. They have it over the Toledo Zoo when it really struck near City Park Ave....

beginning to wonder if they just randomly placed markers in the city...
 

Paul Townsend

I just looked at the tornado that hit my house on April 21, 1974 and the plotted path is also to the south of the actual path...

Now I thought that maybe the path they created was a straight line made from the beginning and ending points of the path, but the ending point of this tornado is not correct either.......plotted south or even southeast of the actual ending point.
 
May 31, 2004
1,895
44
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Peotone, IL
illinoisstormchasers.com
I just looked at the tornado that hit my house on April 21, 1974 and the plotted path is also to the south of the actual path...

Now I thought that maybe the path they created was a straight line made from the beginning and ending points of the path, but the ending point of this tornado is not correct either.......plotted south or even southeast of the actual ending point.

Same with the 1967 Oak Lawn Illinois tornado. I live in a house that was completely destroyed by the tornado and the damage path was 3 mile south of my house according to that page. Overall though its a great job and great tool. Just a few glitches.
 
Apr 7, 2006
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Hm are the plots all off by the same distance? Seems most of the tracks are just south of where they actually were (from the particular tornado events mentioned in the previous posts.)
 

Joey Ketcham

It doesn't even have the tornado track for May 4th, 2003 right. At least not for the tornado that went through Franklin, KS.

It shows the tornado passing south of Franklin.
 
Wow he has a long answer to all of this...he is waiting to be accepted into the forum. Very interesting comments from him though...apparently the lines are drawn by the NWS data. Hopefully he will have his membership accepted shortly. On the same subject from Josh - the owner of the site

On a related note, some of you may have noticed this disclaimer on the tornado details page:

"*The National Weather Service (NWS) data file contains touchdown latitudes and longitudes for all tornadoes. However, lift off latitutudes and longitutudes are not given on all tornadoes. When both are given, an approximate track is displayed. Note that since a maximum of only two sets of coordinates are given, the resulting approximate track must be drawn as a straight line. In reality, the actual path of the tornado between the touchdown and liftoff points can vary significantly, particularly for longer paths. Also note that the path displayed is only as accurate as the data within the NWS data file, which gives coordinates (latitude and longitude) to 2 digits only."
 

Josh Lietz

I apologize in advance for the length of this reply...

Tornado paths are generated via the touchdown and liftoff latitude/longitude points given in the NWS historical data file, which can be found on Dan McCarthy's page here http://www.spc.noaa.gov/wcm/ . Each line within the file represents either a unique tornado or a state specific segment of a multi-state tornado (actually, a 3rd type of line exists that is just continuation data for an event that takes up more than 1 line, but, for simplicity, we can exclude that from this discussion...) For the April 19, 2000 Parsons, Kansas tornado that "jketcham" mentions (shown here http://www.tornadohistoryproject.com/map.php?i=40751) the
corresponding line in the NWS historical data file is:

2000.00,13.00,20.00,4.00,19.00,4/19/2000,19.50,3.00,709.00,1.00,,1.00,1.00,1.00,37.22,95.55,37.42,94.93,340.00,,1.87,5.60,,87.00,0.00,,71.42,125.00,99.00,133.00,37.00,"3",1.87,,"709"

Commas are used as delimiters to separate various pieces of information, but for the purposes of this discussion the relevant numbers are 37.22, 95.55, 37.42, 94.93. These numbers represent the touchdown lat/lon (37.22, 95.55) and the lift-off lat/lon (37.42, 94.93) as explained in the SPC format code instructions here http://www.spc.noaa.gov/wcm/torforma.doc.

As for the actual plotting, the Google Maps API allows for the drawing of "polylines" between any number of points (polylines are the same things that show you your route when viewing driving directions....) In this case, there are only 2 points given in the NWS file: touchdown and liftoff. So,
necessarily, the path generated from these coordinates is a straight line (except for multi-state tornadoes, which have a new set of points at state lines...) Obviously, tornadoes don't move in a perfectly straight line, but zig and zag. The longer the path, the more potential for variation. Additionally, coordinates are only given to a precision of 2 digits. So, the coordinate (37.22, 95.55) could have in reality been (37.2167, 95.517) or something similar, which can probably add up to a difference of a couple hundred feet or so. But since the NWS only gives 2 digits we'll never know. Also, the width (thickness) of the polyline (tornado path) is currently a fixed number of pixels (although I could, in theory, adjust the thickness of the polyline to reflect the reported width of any specific tornado....) One must account for the actual width of the tornado on either side of the polyline. So, a tornado that appears to miss a town (such as Parsons, Kansas) on the map may look that way due to a combination of rounding errors in the coordinates and the non-displayed total path width.

Having said that, I suspect that a good deal of the discrepancies in the displayed paths stem from less than perfect record keeping by NWS, or just plain incorrect information given by NWS personell in their survey (remember, much of the coordinate information was generated in a pre-GPS world...) What I am absolutely sure of is that the information displayed on the map is consistent with the information given in the historical data file. Short of manually researching all 48,000+ tornadoes in the database or collecting eyewitness accounts, I think its the best we can hope for ;)

Even taking the above comments into account, I know that some paths are spot on. For example, a tornado that hopped and skipped its way directly over my sister's house (shearing off the top of a tree in the process) is displayed exactly, and I mean exactly over the location of the formerly healthy tree.

Speaking of eyewitness accounts, that's one of the reasons I have enabled users to leave comments, so that they can add their own experiences to the "official" information given by NWS. I encourage each of you that have noted path discrepancies to leave a comment on the appropriate tornado
details page in order to set the record straight.

On a related note, some of you may have noticed this disclaimer on the tornado details page:
"*The National Weather Service (NWS) data file contains touchdown latitudes and longitudes for all tornadoes. However, lift off latitutudes and longitutudes are not given on all tornadoes. When both are given, an approximate track is displayed. Note that since a maximum of only two sets of coordinates are given, the resulting approximate track must be drawn as a straight line. In reality, the actual path of the tornado between the touchdown and liftoff points can vary significantly, particularly for longer paths. Also note that the path displayed is only as accurate as the data within the NWS data file, which gives coordinates (latitude and
longitude) to 2 digits only."


Somewhere along the line this disclaimer has been inadvertently removed from the general tornado map page. I will be reinserting it shortly.

Thanks for your interest in the site. If anyone has suggestions for improving the site I welcome your comments (I also welcome criticisms :D ...)

Josh Lietz
 
May 1, 2004
3,402
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Springfield, IL
www.skip.cc
This is a fantastic site. I've been dabbling in the Google Maps too, but this is a really impressive use of the API. I think we should all chime in with links to our logs and photos for the tornadoes we've intercepted. I'll contribute to the three I've seen. ;) How do we add photos? Just provide links in the comments section?

Here's a suggestion that may or may not be worth implementing. For the tornadoes that have path width information, perhaps at a certain zoom level you could switch over from a GPolyline to a filled GPolygon rectangle, the width being the actual path width. Although this still wouldn't be that accurate of a representation as this path width would be plotted for the entire length of the track. It might give a little better indication of the size of the tornado, however. (Come to think of it, some tornadoes that only have path widths of a few yards might be really hard to see on the map.)
 

Joey Ketcham

Josh,

Thanks for the fantastic reply! I noticed that your tracks and the ones used by the NWS were similar, so I was wondering if that was the path created and used by the NWS.

Your site is still awesome, a one of a kind. Tonight I will add a link to your site from mine, www.kschaser.com

Joey
 

Josh Lietz

This is a fantastic site. I've been dabbling in the Google Maps too, but this is a really impressive use of the API. I think we should all chime in with links to our logs and photos for the tornadoes we've intercepted. I'll contribute to the three I've seen. ;) How do we add photos? Just provide links in the comments section?
Thanks! Yes, I think that sharing photos, logs, even videos if you have them via the use of links in the comments section is a great idea. I had initially thought that I would get users to submit photos, videos, etc..., and then store them on my server, but the more I think about it the more I think that just posting links in the comments section is the best way to go. Plus, it might drive more traffic to your site, so its a win-win situation. I encourage everyone to do this...

Here's a suggestion that may or may not be worth implementing. For the tornadoes that have path width information, perhaps at a certain zoom level you could switch over from a GPolyline to a filled GPolygon rectangle, the width being the actual path width. Although this still wouldn't be that accurate of a representation as this path width would be plotted for the entire length of the track. It might give a little better indication of the size of the tornado, however. (Come to think of it, some tornadoes that only have path widths of a few yards might be really hard to see on the map.)
I had considered something similar. However, as you have indicated, the "path area" would be the same for the entire path. Complicating this, the methodology for reporting the path width has changed over the years. To quote the SPC format instructions:

Prior to 1996, this is mean tornado path width (if known)...The mean width along the entire track is reported...The minimum width is assumed to be 30 feet...For 1996 and later years, this is maximum path width to correspond to maximum damage used for the F-scale.

I guess I'm just not sure how I could effectively portray the entire path area, particularly for large tornadoes that start rather small :confused:
 

Josh Lietz

...Tonight I will add a link to your site from mine, www.kschaser.com
Thanks! The more links to the site the better...I've had the site up and running for a couple of months now, but am only averaging 64 visits a day. Although yesterday set a new record with about 330 visitors, mainly thanks to this topic and another one over at easternuswx.com.
 
May 1, 2004
3,402
734
21
Springfield, IL
www.skip.cc
In addition to centering when the user clicks a marker, how about a pop up with a link to the tornado's information/links page when you click the marker? And perhaps an added filter feature at the top for tornadoes with additional user added information such as pictures/video/comments.
 
Thanks! Yes, I think that sharing photos, logs, even videos if you have them via the use of links in the comments section is a great idea. I had initially thought that I would get users to submit photos, videos, etc..., and then store them on my server, but the more I think about it the more I think that just posting links in the comments section is the best way to go. Plus, it might drive more traffic to your site, so its a win-win situation. I encourage everyone to do this...



I had considered something similar. However, as you have indicated, the "path area" would be the same for the entire path. Complicating this, the methodology for reporting the path width has changed over the years. To quote the SPC format instructions:

Prior to 1996, this is mean tornado path width (if known)...The mean width along the entire track is reported...The minimum width is assumed to be 30 feet...For 1996 and later years, this is maximum path width to correspond to maximum damage used for the F-scale.

I guess I'm just not sure how I could effectively portray the entire path area, particularly for large tornadoes that start rather small :confused:
When I have some free time I will go back and try to add some links to the bigger events in this region. KPAH does a great job of keeping archives.

Good work!!!!
 

Josh Lietz

In addition to centering when the user clicks a marker, how about a pop up with a link to the tornado's information/links page when you click the marker?
I think I might do something similar to what you suggest, but instead of a pop up, the index number of the tornado that is clicked on will automatically appear in the "See Details/Comments" section on the left menu. Then the user will simply need to click "Go" to be forwarded to the details page.

And perhaps an added filter feature at the top for tornadoes with additional user added information such as pictures/video/comments.
I'm not sure if I'll be able to integrate that on the map page (screen real estate is getting scarce!), but your suggestion has inspired me to retool the comment section so that the user can also "classify" his/her comment. For example, a user that is posting a link to a photo will be able to check a box labeled "photo" adjacent to the "Add Comment" button (or for a link to a video a checkbox labeled "video", or chase log with checkbox labeled "chase log"...) Since comments will now have classifications, I'll be able to easily integrate a filter for pictures/video/etc in the Tornado Database section. I hope I described what I have in mind somewhat clearly, but if I do it right should be easy to use once I get it done (could be a few weeks...)

In the meantime, go ahead and keep submitting comments. I'll retroactively classify them when I'm done.