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Geographic Information System Development
for the
Water Division of the City of Cleveland
by
The Northern Ohio Data and Information Service (NODIS)
Maxine Goodman Levin College of Urban Affairs
Cleveland State University
NODIS Responsibilities
As a subcontractor to Metcalf & Eddy, an engineering consulting company, NODIS lead the two year development of an advanced Geographic Information System (GIS) for hydraulic modeling and other GIS applications for the City of Cleveland Water Division (CWD). NODIS was responsible for evaluating and recommending GIS software and geographic databases (including the base map), GIS database design, management of the digital conversion of water distribution infrastructure maps, some specialized tool applications development, selected database enhancements, and GIS software training.
The Division serves a population of 2.3 million persons and over 400,000 customer accounts with over 5,300 miles of pipes and appurtenances, 4 water treatment plants, 17 secondary pumping stations, and 13 primary and 75 secondary pressure zones. Environmental Systems Research Institute (ESRI) GIS software was selected for the project. Base maps include the county’s digital orthophotography, associated planimetry, and cadastral databases. The infrastructure database includes water mains, valves, hydrants, and other water distribution facilities. The GIS database (managed by ESRI’s SDE database software) interfaces with an Oracle database and provides input to the hydraulic, surge, and water quality models, as well as mapping of model results. The project required very significant enhancement to the water distribution model and tools provided by the ArcGIS software system.
Project Description:
Base Map Layers & Other Data Layers:
Description
Origin or Source
Accuracy
1,132 Planimetric Files for each layer
Methodology to Convert: Translate each file from AutoCAD drawing file to ArcInfo format
Append each file to create ONE seamless coverage for the each of the 9 planimetric layers
Create the Cleveland Regional Geodetic Survey (CRGS)projection
Developed from March, 1993 Digital Orthophotographs
Files acquired from Cuyahoga County Engineer’s Office
Scale 1” = 200’ 1,132 Digital Files
Planimetric Base Map
Planimetric Base Map:
Each data layer is seamless with a geographical coverage of Cuyahoga County and approximately 2 miles outside the county extents.
Curbs
Building Footprints
Railroad
WaterwayHighway
Retention Wall
RecreationArea
Tree
Bridge
Accuracy of Planimetric Data
Approximately ± 5 feet in positional accuracy from the 1” to 200’ scale orthophotography
An additional ± 2 feet after defining the CRGS projection, a local projection, based on known control points
Missing any changes between March 1993 and the present such as new subdivision development or building demolition, etc.
Comprised of Parcel Properties
Seamless Parcel Polygon Data Layer
Geographic Coverage- all Cuyahoga (1994) and Medina County (1999), northern portion of Summit County (2000)
Cadastral Base Map
Cadastral Accuracy
In Cuyahoga County:
Parcel layer current to November 1994.
Parcel splits or combinations since November 1994 are not present.
In general, the parcel layer is relatively spatially accurate compared to the planimetrics.
However, there are many occurrences in which parcels are less spatially accurate.
Planimetric curb has higher degree of spatial accuracy
Some groups of parcels required moving to conform to the planimetric curb.
Improving Cadastral Accuracy
GOAL:
To increase the relative positional accuracy of parcels to the planimetric curbs
APPROACH:
Accomplished through moving blocks of parcels and trimming parcels where appropriate
RESULT:
Relative location of parcels and aesthetic appearance was improved
Facilitated the use of the “Connection Tool”
Moved and/or Trimmed Parcels
Example: red parcels intersect the curb on northern end.They are moved as a group to conform to the curb layer.
Moved and/or Trimmed Parcels
BEFORE AFTER
Parcel Adjustment Statistics
Total number of parcels 499,027
Parcels moved or centered in relation 120,53824%
to curb
Parcels trimmed 2 feet from curb 4,6430.9%
Summary: Planimetric and Cadastral Layers
Planimetric layer has highest spatial accuracyParcels were adjusted, where necessary, to planimetric
Relative accuracy levels are acceptable for the hydraulic modeling project and other water department applications
Recently developed areas since 1993 (planimetrics) and 1994 (parcels) have undergone change and need to be updated.
Summit and Medina Counties both required the creation of a pseudo-curb layer.
Other Land Base Data Layers – Triangulated Irregular Network (TIN), Cuyahoga County, 1993
Developed from the Digital Elevation Model (DEM) data acquired from the Cuyahoga County Engineer’s Office
DEM files created from the orthophotos in CRGS coordinate system
From the DEM elevation mass points and breaklines, TIN was created using the linear bivariate method
TIN was re-projected to U.S. State Plane (NAD83) feet
Large file size of 826 MB
Triangulated Irregular Network
As the TIN contains the elevations of each corner, calculations can be made to find the elevation of any point within the triangle.
955.895 936.985
942.133
945.876
Accuracy of TIN Data
Positional Accuracy similar to Planimetrics: approximately ± 5 feet
90% of selected TIN elevation values were within ± ½ foot of spot elevation value from planimetrics
(elevation difference due to differences between linear bivariate method and the quintic method)
Combined TIN for Medina and Summit Counties
Developed from United States Geological Survey (USGS)7.5 ‘ quadrangles
Locational errors can be up to 200 feet
Other Land Base Data LayersModified street centerline file:For Cuyahoga County:Source is 1997 TIGER street centerline file from Census BureauConflated to fit within planimetric curb
For other 6 surrounding counties:2000 TIGER street files were appended to 1 street file Positional accuracy at any point can be ±200 foot
TIGERModifiedTIGER
Other Land Base Data Layers
Traffic Analysis Zones (TAZ)Zones developed by NOACA and AMATS for Census BureauAttribute data population values and estimates 1990 to 2025
Waterways 2000 TIGER Census Bureau waterways for 7 counties
City BordersBased on planimetric and parcel layers for Cuyahoga, Medina,
and Summit Counties. Other 4 counties are based on 2000 TIGER
files
LanduseBased on Ohio Department of Natural Resources (ODNR)
landuse maps from 1976 to 1985 for 7 counties. Appended to 1 landuse data layer
Other Land Base Data Layers
Zoning 1997 zoning developed for NOACA 5 county zoning coverage- Cuyahoga, Lake, Geauga, Lorain, & Medina Appended to 1 zoning data layer TIGER level accuracy
Wards2001 political voting wards for City of Cleveland Conflated to planimetric/ parcel layers
Telephone Area Codes and Postal Zip CodesCovers 7 countiesTIGER level accuracy
Populating the Database
Methods
Fit to base map
CWD Section Sheet Index Map
Populating Methods
Digitizing 113 section sheet maps at 1” = 400’ scale
113 section sheets scanned to create raster image
Water features digitized from image using AutoCAD
AutoCAD .dwg files converted to GIS format- ESRI shapefiles
Digitizing 113 section sheet maps at 1” = 400’ scale
113 section sheets scanned to create raster image
Water features digitized from image using AutoCAD
AutoCAD .dwg files converted to GIS format- ESRI shapefiles
Populating Methods
Example of Section Sheet
Captured Features:
Description:
PIPE
Line feature with diameter attribute. 1 pipe segment defined as pipe intersection to pipe intersection, or to diameter change.
Valves
Point features with status attribute.Types are system, control, and flush pipe valves.Status: closed or open.
Hydrants
Point feature at insertion along pipe. Hydrant type and direction also captured.
Populating Methods - Features Captured from Facility Maps:
Facility (Point Feature)
Pump Station, Reservoir, Tower, Surge Tank, Vault, Maintenance or Treatment Plant
Pump, Pump Motor, Venturi, Master Meter (Point Features)
Valve (Point Features)
Drain, check, pump control, air, control, flush, or air cock.
Pipe (Line Feature)
Contains Diameter Attribute
Fittings (Point Features)
Created at pipe segment ends and when diameter changes
Schematic DrawingsScales Vary from 1” = 5’ to 1” = 100’
Populating Methods - Feature Attribute Population
Pipe Type attribute values were populated using spatial & attribute queries:
Diameter >= 20”
Trunk MainYes
Length < 400’No
Intersect aTrunk Main
Yes
Supplemental ConnectionYes
Distribution MainYes
HydrantAttached
No
Circulation MainNo
Distribution MainNo
Populating Methods
Detailed drawings of trunk mains were used to populate the locations of the following point features:
Air cocks Access manholes Automatic air valves Drain valves Electrolysis test stations Pitometers
Attributes recorded- size, manufacturer, class, pressure rating, internal coating, material, and year installed
Populating Methods
Populate connections:Using the custom connection tool, a connection line, fitting,meter, and curb stop is generated for each water customer
to the associated parcel.
Multiple connections to a parcel can exist
From the customer billing database, customers linked to a parcel by:
Matching ppn in billing to ppn in parcel database or Matching address in billing to address in parcel
database
A connection is generated when parcel PPN or address matches billing database
Populating Methods – Single and Multiple Connections
Connections consist of the following:
Connection Line •Drawn perpendicular from the closest distribution or circulation main toward the parcel centroid.•Terminates 6 feet inside the parcel frontage.•Multiple connections to a customer parcel generated where applicable
Curb Stop •Point Feature•Created and placed 3 feet outside the street pavement.
Meter•Point Feature•Created and placed 5 feet inside the parcel frontage.
Fitting•Point Feature•Created at the junction of a pipe and connection.
Populating Methods
Populate installation date of distribution & circulation mains: Based on connection date and hydrant type
Connection features are linked to pipe features. Oldest connection date is determined (based on connection number).
Hydrant features are linked to pipe features. Ear or no ear hydrants are determined from hydrant type.
NO EARS
EARS
If pipe has oldest connection prior to 1955 (with or without hydrant ears):
Installation date is the oldest connection on the pipe If pipe has oldest connection after 1955 & hydrants without ears:
Installation date is 1955 If pipe with oldest connection after 1955 & hydrants with ears:
Installation date is the oldest connection on the pipe
Populating Methods
Populate pipe cleaning and lining data: Used Paradox cleaning & lining database from CWD Identified pipes that correspond to cleaning & lining records Generated/ updated cleaning & lining fields in geodatabase related table
Populate control valve settings & diameter: Used regulator database from CWD Settings and diameters fields updated to control valve feature
Populate pumps & storage units: Pump curve data provided by CWD linked and updated to pump table Storage unit shapes also provided by CWD and linked to storage units
All point features snapped (snap tolerance of 1/10 foot) to pipe. The snapping was performed while digitizing in AutoCAD as well as snapping features when creating the geodatabase.
To ensure network connectivity:
If there was a missing point feature present at pipe ends (when creating the water network), a network junction was generated.
The missing point feature (replacing the network junction) was added to the network.
A network connectivity tool was also used to ensure that all features were in the geodatabase network.
Checking Network Connectivity
Statistics
Schema size:Schema size:Tables Tables 223223
Attributes Attributes 3,2933,293
Relationships Relationships 230230
Domains Domains 7070
Subtypes Subtypes 1212
Schema size:Schema size:Tables Tables 223223
Attributes Attributes 3,2933,293
Relationships Relationships 230230
Domains Domains 7070
Subtypes Subtypes 1212
Pipes: 53,223 pipe Pipes: 53,223 pipe segments; 5,237 milessegments; 5,237 miles
Trunk main: 422 milesTrunk main: 422 miles
Trunk main survey points: Trunk main survey points: 11,29111,291
Fittings: 342,611Fittings: 342,611
Hydrants: 70,879Hydrants: 70,879
System valves: 56,098System valves: 56,098
Flush Pipes: 1,301Flush Pipes: 1,301
Pumps: 100 Pumps: 100