GEOG5222 Lesson 3

Analyzing Spatial Data in a GIS: Locating Tornado Relief Sites

John Taber

    
Full view   Figure 1:  This is the final data, for the state of Oklahoma, showing population density by county, as well as the Relief Priority Zones and Candidate Relief Sites created in this activity.
Close   Figure 2: This shows a close-up view of Figure 1.  Emergency Relief Zones were created by buffering the paths of tornadoes that hit the area on May 3, 1999, and then intersecting them with counties.  The relief priority (1 is the lightest, and 5 the darkest) is derived from tornado intensity and county population density.   Candidate Relief Sites were identified from schools, hospitals and churches in the relief zones.
NAME FTYPE Latitude Longitude GAVPRIMARY
Good Hope School school 35.62444 -98.36611 821
Canaan Church church 35.32833 -98.13028 1146
Broxton School school 34.98639 -98.40750 1312
Mount Zion Church church 34.98583 -98.40111 1318
Grandview Church church 35.69667 -98.26417 1377
Mount Zion Church church 35.62417 -97.92278 1397
Park View Hosptial hospital 35.53028 -97.98028 1410
Amber School school 35.15972 -97.87417 4340
Bridge Creek School school 35.23222 -97.71944 4348
Friendship Church church 35.24028 -98.02389 4377
Mennonite Church church 35.05833 -98.05750 4402
Nazarene Chapel church 36.02917 -97.83639 5601
Little Zion Church church 35.65194 -96.76972 6541
Central Church church 35.94583 -97.59500 6664
Saint Margaret Mary Church church 35.96000 -97.59417 6758
Albert High School school 35.44472 -97.35333 8835
Country Estates School school 35.45583 -97.39500 8886
Delcrest Junior High School school 35.45750 -97.43000 8901
Douglas Church church 35.62361 -97.24639 8907
Jarman Junior High School school 35.44139 -97.39972 8973
Kerr Junior High School school 35.44056 -97.42722 8978
Monroney Junior High School school 35.46306 -97.39306 9018
Nicoma Park Junior High School school 35.48167 -97.32750 9030
Roosevelt School school 35.47111 -97.39806 9078
Soldier Creek School school 35.45000 -97.36944 9111
Townsend School school 35.42556 -97.43528 9143
West Side School school 35.43778 -97.40444 9166
Willow Brook School school 35.47944 -97.38500 9181
Willow View School school 35.23139 -97.10611 10951
Figure 3: This table shows the Candidate Relief Sites gathered.

Conclusions: The data gathered and analyzed here has one critical flaw: it assumes that population denisty within a county is uniform.  This is not realistic, especially in (inconsistently) urbanized areas such as this one.  A careful examination of the Emergency Relief Zones in adjoining counties, on the same tornado path, shows that the priority might differ greatly on opposite sides of a county line based on overall county density, but the local density might be the same on either side.  One alternative might be to derive population density by census tract, rather than by county.

In addition, this study only examined three possible categories of relief site, and did not consider others.  No consideration was made as to accessibility of these facilites.  One other theme that might be considered would be one showing major highways, to help quantify the potential for accessibility.
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