Intro to GIS - Week 12
This week was a three part assignment. In Section 1: Geocoding, we downloaded a Tiger All Lines shapefile for Lake County, Florida. This file included streets, water features, railroads and trolleys. We then also imported a table of EMS site addresses from out student assignment files to the same geodatabase. The information in the two files was then standardized using the Address Locator function. With this new feature class we were then able to geocode our data, matching addresses from the table to geographic locations on the map. This process was successful in matching most of our addresses, but our unmatched rate was over the general guideline of 5% or less so we then had to manually rematch some of the unmatched addresses. We did this in two steps. For some of the unmatched addresses there were possible candidates listed. We zoomed to these candidates and compared them to the location of the unmatched address in Bing Maps. If a candidate seemed a close enough match we selected it. Otherwise, we handled it as we did in the next step of rematching unmatched addresses that didn't have any candidates. Using Bing Maps we found the location, then used a cross street as a reference to zoom to using Select by Attributes and determined the most likely location on our map. Once we were pretty sure we knew where the address was located we selected the Pick Address from Map option and linked the address to it's geographical location.
In Section 2: Network Analyst, we used the geocoded data from Section 1 to create a simple route map of three of the EMS sites using the Network Analyst tool. This was a pretty simple process. We started by creating a route analysis layer using the New Route tool, then added stops to the route using the Create Network Location Tool. Once our stops were selected we set up the parameters for analysis. There were lots of options here to choose from including Impedance, Using Start Time, Use Time Window, Restrictions and several more. After setting all the parameters we selected solve and it created a route of our three stops as shown in the enlargement of this map.
For Sections 3: Model Builder we got most of our instructions from the ESRI Virtual Campus Training. For this exercise we used a model that had already been created and just made a few adjustments to it. The model was designed to locate areas around schools where the gas utility company will regularly check for gas leaks that are too close to the school. We opened this model through the edit feature then explored some of the elements. The first half of the model was in color and so ready to run, but the second half was still white, indicating it was missing a piece of data. One of our variables was missing a value so we had to enter that. Once we did the rest of the model switched to colored and was ready to run. With the model now ready to run we chose Run Entire Model from the Model menu.
When a model has been successfully run the model tool and output data elements will be shadowed. Mine weren't. I went back through the instructions step by step and knew I had run it correctly, but I couldn't figure out what I had done wrong. Since I didn't know where the problem was I deleted everything and recopied all the files for the assignment and started again from scratch. And failed again. After the third failure, before starting again from scratch, I went back to the beginning of the lab instructions before the ESRI instructions and reread them..a few times. Finally the last line of instruction clicked and I realized while I had "explored" all of the elements in the model I never went in and reset the output location for anything to my own working folder. So I went back in and checked every element again, to verify if there was anything in each one that required any changes, fixed what needed fixing then ran the model again. Finally with success.
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