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