Auditing 9-1-1 GIS
Data
Proving What You Have
Indiana GIS Conference
February 2010
Overview
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Decide on what you want to verify
Identify/Establish Accuracy Standards
Techniques for verifying data
Techniques used in the KY Geospatial audit
Issues discovered
Options implemented for correction
Benefits of self audit
What’s Important?
The most important components of a GIS are people.
Trained people, who understand GIS as well as E9-1-1,
play a vital role in a successful GIS. People, who
create and maintain the data as well as those who use
the GIS are key to successful E9-1-1 implementation.
The procedures, processes, and techniques these
people use in developing and using a GIS are critical
to reaching an informed decision.
What’s Important
No matter where you get your data, you have to
assume responsibility for the accuracy,
completeness, and currency of the data. The map
data must agree with the MSAG data, otherwise the
ALI will not display the correct information on the
visual map.
A Public Safety Answering Point Managers’Guide to Geographic Information Technology, A
National Emergency Number Association White Paper, October 2002
What to Test
• General GIS data
– Geocoding accuracy
– Centerline accuracy
• Wireless 9-1-1 information
– Is the right information being provided?
– How accurate is that information?
• Both
Standards? What Standards?
• Geocoding Accuracy
– How close does it need to be?
– State or local choice
– In Kentucky geocoding results shall be accurate to
within 0.1 mile
• Centerline Accuracy
– Accurate representation of the roadway?
– How close does it need to be?
Standards? What Standards?
• Wireless data standards
– FCC Standards are based on a national view
• Network Based Location Solutions
– 95% of the time <= 300 meters (984 feet)
– 67% of the time <= 100 meters (328 feet)
• Handset Based Location Solutions
– 95% of the time <= 150 meters (492 feet)
– 67% of the time <= 50 meters (164 feet)
Local Standards
• Identify or establish what you will use locally.
– National, state, local.
– Treat it like a law, you may be stricter than the
higher jurisdiction but never less.
• Document the accepted standards.
– Makes it easier to repeat the process.
– Makes it easier to compare results and measure
improvement.
Kentucky Geospatial Audit
Authority
The Commercial Mobile Radio Service Emergency
Telecommunications Board (CMRS Board) is
charged with administrating the CMRS fund for the
purpose of implementing wireless emergency
Enhanced 911 service throughout Kentucky in
accordance with State and Federal Legislation and
Regulations.
202 KAR 6:100
(4) Each PSAP's mapping shall be tested for the accuracy of road centerline
data. A minimum of twenty (20) randomly-selected address points shall be
tested in each PSAP response area. If a PSAP response area encompasses
multiple counties, a sampling of a minimum of twenty (20) randomlyselected address points per county shall be tested. Tested locations shall:
(a) Be distributed across the PSAP response area to yield a valid cross
section of urban and rural environments;
(b) Plot on the correct side of the street as shown on the base map data
supplied by the PSAP;
(c) Plot within the correct cross streets as shown on the base map data
supplied by the PSAP; and
(d) Plot within one-tenth (1/10) of a mile of their location on PSAP
supplied base maps.
Standards Influence the Process and
Techniques
• 20 random points
– Process to generate 20 random points through out
the jurisdiction.
– Distributed between urban and rural.
• Think incorporated and unincorporated
• Think city and township
• Hawth Tools
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Generate 20 points per county
Generate 3 points per incorporated area
Snap to centerlines
Random selection of 20 final points from
combined set
Standards Influence the Process and
Techniques
• Data must plot within certain parameters to
supplied data
– What elements should be compared?
• Field collected points both XY and field collected
addresses
– Using GPS equipment
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Navigate to the random point
Identify the nearest posted address and record address
Take a GPS fix of the driveway or actual structure
Repeat as necessary
Standards Influence the Process and
Technique
Standards Influence the Process and
Technique
• Equipment used:
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ArcView with Network Analyst
Trimble GeoXT with external antenna
ArcPad 7.x on laptop
Digital camera
Access
Overview of the Initial Kentucky Audit
• Collected data in 120 counties and 5 additional
PSAP jurisdictions
• 2666 data points collected
• Teams traveled more than 13,000 road miles
Overview of the Initial Kentucky Audit
Applying the Standards
• Test collected data
– Test in the dispatch office with the data being used there
and the mapping solution being used.
• Discoveries
– 46% of the field data points failed the standards.
– GIS data not necessarily the same as in the dispatch office.
• Out of date data in dispatch
• More current in dispatch center
– Mapping solutions did not display data according to the
standards.
• Did not offset to left or right of centerline segment
• Introduced rounding errors that reduce accuracy
• Would not accept LAT LONG entry
Results of 1st part of Geospatial Audit
• PSAPs that passed
– Very involved in address assignment and GIS data
maintenance
– Active communication and data exchange between
governmental agencies and emergency services
– Proactive on data verification and validation
Results of 1st part of Geospatial Audit
• PSAPs that did not pass
– Reviewed results and created a correction plan
• Data improvement
• Software/hardware updates and changes
– Improving communication and data exchange
– All PSAPs re-audited have passed showing
significant improvement in data and function
Correction Plans
• Update, upgrade, change mapping solution
– Several software issues were corrected by the
vendors of the CAD/Mapping solutions.
• Update, correct, rebuild GIS data
– Scrub and correct all segment ranges reflecting
actual ranges and not theoretical ranges
– Develop point address layer
Wireless Data Audit Criteria
(3) Audits shall verify that upon receipt of a wireless
911 call the PSAP's mapping component shall:
(a) 1. Display the X, Y coordinates on digital base maps used
by the PSAP;
2. Identify the incoming 911 call on the map display; and
3. Identify the closest assigned address to the X,Y [of the
caller] coordinates provided; or
(b) In the absence of the X, Y coordinate information, [of the
caller] identify the cell site, and cell-face.
[CMRS interpretation is that it should be done automatically
upon receipt of the call]
Why this Criteria?
• Currently the majority of wireless 9-1-1 calls
are routed to PSAPs based on tower face.
• Next Generation 9-1-1 (NG9-1-1) will
incorporate routing based on X, Y.
Tower Sectors
•Most Towers are divided
into “faces” or “sectors”
•Each has a unique routing
number and should have a
unique address entry.
•123 Any St – NW
•123 Any St – E
•123 Any St – SW
•pANI/ESRD/ESRK directly
related to cell face/sector
Tower Sectors
Wireless Audit
• Function or accuracy or both
• If accuracy, consider auditing the accuracy of
the data provided with the intent of fully
understanding the capabilities of the current
implementations.
– Do not expect to take the data and bring about
change in the wireless carriers
Wireless Audit Approach
• #1 – Analysis of data captured at the PSAP
– Run a report for wireless calls that are related to a
specific street address.
– Plot distribution of the X, Y data provided.
– Compare the X, Y data provided with the address
data. Test if it meets the wireless criteria.
Wireless Audit Approach
Wireless Audit Approach
• #2 – Field data collection
– Navigate to random addresses similar to the
approach described earlier
– Make test 9-1-1 calls
– Compare the collected X, Y with the address
Wireless Audit Findings
• Some Phase II calls acted as Phase I calls
– X, Y was of the receiving tower
– X, Y did not change with rebid
• Large variance in location accuracy
– Issues based on system being used
– Some very accurate
– Some very inaccurate
Benefits of a GIS Audit
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Opportunity to get more people involved
Identifies areas for improvement
Provides a better product
A better product means better service
Questions?
James Morse
GIS Project Manager
Stantec Consulting Services Inc.
1901 Nelson Miller Parkway
Louisville, Kentucky 40223
Ph: (502) 212-5044
Fx: (502) 212-5055
james.morse@stantec.com
stantec.com