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Thursday, May 12 • 10:30am - 10:50am
911, What's Your GIS Emergency? - Using GIS to Help Emergency Response

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The GIS data in Merced 911 dispatch is being used to help people and the absence of block address points within the GIS address point file was hindering the dispatchers from being as efficient at their jobs as they could be. Also, since a point needed to be created for every block for every street within the city, it wouldn’t be as simple as adding the extra points manually. The first solution started with the existing road centerline file as the source data while using the Feature to Point tool in Arc Tool Box. This tool generated a point on the midpoint of each line segment in the road centerline file. These new points retained all the attributes of the road centerline file. A new field [BLOCK] was added to the new point file and was populated by using rounded values (to the nearest hundred) of an existing address range field ([RADD_FR]). Another field was added [ADDRESS] and it was populated using a concatenation of the new field values, string, and an existing street name field [STREET]. ([BLOCK] &""&"BLOCK OF"&""& [STREET]).

The DeleteIdentical tool was used to delete the records in the [ADDRESS] field that had identical values. These points could now be merged with the master address point file. At first glance, it seemed that the problem had been solved. However, upon further investigation, it was found that there were many blocks that didn’t have a corresponding address point. This was the case whenever the road centerline segment spanned multiple blocks from intersection to intersection. For instance, if a road centerline had a range of addresses from 200 to 800, an address point for the 200 block would be created but address points for the 300 block through the 800 block would not, since the Feature to Point tool creates just one point per line segment. Too much data was missing for these new address points to be useful for the 911 dispatchers.

The project needed to be redone, this time using a copy of the master address point file as the source data. New fields were added and populated using the same methods that were used previously, except an existing house number field was rounded instead. Records that had identical values were deleted. Upon inspection of the data, it could be seen that the new dataset was very comprehensive and there was an address point for virtually every block, with just a few exceptions. Finally, Python scripting was used to move each address point from its original location and snap it to the nearest road centerline segment with the same street name. The new points were added to the master address point file for the 911 dispatchers to use. Using ArcGIS helped to transform valuable GIS data into something even more beneficial and kept this project from being laborious and tedious. Those who distribute GIS data may need to generate points like this to make the data more useful to emergency responders.

Natalia Austin, GISP, GIS Analyst, Merced County Association of Governments, Merced, CA
RuthAnne Harbison, GISP, GIS Coordinator, City of Merced, Merced, CA

avatar for RuthAnne Harbison, GISP

RuthAnne Harbison, GISP

GIS Coordinator, City of Merced
RuthAnne Harbison, GISP, GIS Coordinator for City of Merced. Professional associations include CGIA, CentralCal URISA, San Joaquin Regional GIS Council, CalGIS, and hosted 4 GeoSummits at UC Merced.
avatar for Natalia Austin, GISP

Natalia Austin, GISP

GIS Analyst, Merced County Association of Governments
Natalia Austin has been in the GIS field for 18 years. She is a GIS Analyst for Merced County Association of Governments. MCAG disseminates GIS data and facilitates GIS projects in Merced County.

Thursday May 12, 2016 10:30am - 10:50am PDT
Palm East