Convincing the Chief Continued from page 51 6. Open the table for this file and locate the East and North fields. Using these and applying the correct Washington State Plane coordinates, the data can be registered. 7. In the TOC, right-click Trial_Runs_1. dbf and choose Display XY Data. Set the X Field to East and the Y Field to North. Click Edit. 8. In the Spatial Reference Properties dialog box, click Select and specify NAD_1983_ S t a t e P l a n e _ Wa s h i n g t o n _ N o r t h _ FIPS_4601_Feet from the choices under Projected as the coordinate system. Click OK and OK to exit both dialog boxes. 9. After Trial_Runs__1Events loads, rightclick on it and choose Data > Export Data. Apply the data frame's coordinate system, name it Trial_Runs_1.shp, and store the file in \SHPFiles\WASP83NF. Do not add the shapefile to the data frame. 10.Next, double-click on Time Runs, the layer that has a broken data connection, and set Trail_Runs_1.shp as its data source. Remove Trial_Runs__1Events. 11.Make the Trial Runs layer visible and inspect its points. Each point is labeled to show the station, time interval, and run code. Switch from Layout View to Data View. 12.Save the project. Building and Solving an OD Cost Matrix for Station 71 The next task will be building three origindestination matrices--one for each station and its time run data. There are many ways to build and analyze this run data, but creating a separate matrix for each station will allow quick viewing of statistical data for each time subset. There are more sophisticated ways to model and present this data, but this exercise uses a simplified approach. After creating the matrix for Station 71, the process will be repeated for Stations 74 and 76. 1. Be sure that the Network Analyst toolbar and window are available. Click on the Network Analyst drop-down in the toolbar window and choose New OD Cost Matrix. 2. In the TOC, right-click on OD Cost Matrix (just created) and select Properties. In the General tab, rename the layer Station 71. Click the Accumulation tab and check the Length_Mi and Minutes boxes. In the Analysis Settings tab, verify that Impedance is set to Minutes. 3. Open attribute tables for Time Runs and Selected Fire Stations layers. In the Selected Stations table, select the only record for Station 71. In the Trial Runs table, use an attribute query to highlight all 22 records for Station 71. 4. In the Network Analyst window, right-click on Origins and select Load Locations. In the Load Locations dialog box, set Sort Field to INDEX. For the Name Property, click on Field and choose LABEL. Under Location Position, choose Use geometry and specify 500 and Feet for the search tolerance. Click OK. Verify that the single Station 71 record in Selected Fire Stations is selected. 5. Right-click on Destinations, choose Load Locations, and select the 22 records for Station 71 selected in the Trial Runs attribute table. In the Load Locations dialog box, set Sort Field to INDEX and the Name property field to LABEL. Be sure that the correct (i.e., selected) 22 records load. If non-Station 71 records load, delete them and reload the correct ones. (Note: Do not delete records when modeling Concentration because the tabular join to INDEX, necessary for this operation, will fail.) 6. Create new OD Matrices for Stations 74 and 76 using this procedure. Be sure to select and load the correct origin and destination records. Rename each OD matrix and group all matrices in one group layer named OD Cost Matrix Group. 7. Save the project. In ArcCatalog, create a new network dataset. Create a new attribute, Length_Mi, for this network dataset with Cost as the Usage Type and Miles as the Units. Set the default values for the Minutes evaluator and use the new Global Turn Delay for the type of turn. Create an events layer from Time_Runs_1. dbf and export the georeferenced data to a shapefile. Set the Seconds delays field values in the Global Turn Delay evaluator as shown here and listed in Table 1. 52 ArcUser Spring 2009 www.esri.com