DIGITAL TAX MAP

COMMITTEE

DIGITAL TAX MAP

COMMITTEE

The mission of the Committee is to help New Jersey governments create a digital parcel foundation that is reliable, available, and current to support government operations and facilitate the sharing of core land information.

Lewis H. Conley Jr., PLS & PP, Vice President, van note-harvey associates, pcSam DiDonato, CTA, Supervisor Tax Map section, NJ Division of TaxationKelly Heppe, County Tax Administrator, Camden CountyDavid Kunz, GISP, GIS Manager, Sussex CountyPatricia Leidner, GISP, Coordinator, Geographic Information Systems,

Hunterdon County Patrick McDonald, GISP, Senior CAD/GIS Specialist, Montgomery TwpMary Mastro, CTA, SCGREA , Assessor -Franklin Twp, Lebanon Twp, and

Readington Twp, in Hunterdon CountyDana Max, Office of Treasury Technology, NJ Dept. of TreasuryRichard Rehmann, GISP, Vice President, Civil Solutions Andrew Rowan, PhD, GISP, Director of the Office of GIS, OIT, State of NJDonald Walby, PLS & PP, Chief of Survey, KS Engineers, PC. Lyna Wiggins, PhD, Professor, Bloustein School of Planning and

Public Policy, Rutgers UniversityDIGITAL TAX MAP

COMMITTEE

• Benefits & impacts of digital tax mapping• Synergies between digital tax maps & land- based data• Support & resources for implementation

Primary Objective• Maintain a solid, sustainable foundation available for all

to support a variety of operationsDIGITAL TAX MAP

COMMITTEE

Collective Benefit• Information is cross-jurisdictional• Individual functions support multiple uses• Areas of overlap provide benefit-rich opportunities

Spatial Location• Common element to most data• Tax Map is the source for the foundation layer• Leverage for maximum use, benefit DIGITAL TAX MAP

COMMITTEE

DIGITAL TAX MAP

COMMITTEE

• 80% - 90% of all government data information relating to a geographic location – such as street address and block/lot

• Provide a powerful tool to manage & analyze resources and improve decision making

• Streamline current procedures by replacing manual procedures with automated ones

• Reduce or eliminate duplication of effort between offices and agencies

• Improve quality & timeliness of service and information to the public

• Protect against the loss of valuable maps and records due to a natural disaster

By coordinating the tax map, Assessor’s database, and building permit information- approximately $206 million in added assessments, and $531 million in additional in-lieu assessments were identified over the past 5 years.

DIGITAL TAX MAP

COMMITTEE

Approximately 205,000 land parcels on 1,700 tax maps in 37 Municipalities.

Approximately 188,000 MOD IV tax assessment records.

Discrepancy presents unique challenges.DIGITAL TAX MAP

COMMITTEE

Phase 1 – Paper Tax Map Conversion.

Phase 2 – Update map to current parcel boundaries.

Phase 3 – Maintenance & Distribution. Long- term data

DIGITAL TAX MAP

COMMITTEE

Parcels on the map have no tax record in MOD IV

MOD IV tax records are not represented by a parcel on the map

Lot 10Lot 11Lot 12Lot 15

13

10

12

15

11

14

Map

10

1512

17

11

16

Lot 10

Lot 11

Lot 12

Lot 13Lot 14Lot 15

Lot 16

Map

Table

Table

“Golden Triangle”

Municipal Planning Board

Municipal Tax Assessor

Parcel Datamaintenance process mustbe in the loop to keep map

current!!

Land Surveyor

DIGITAL TAX MAP

COMMITTEE

• Public Safety – 911• Prosecutor’s Office• Health Department• Economic Development• Legal Counsel• Election Board• Tax Board• Many Municipalities

DIGITAL TAX MAP

COMMITTEE

Citizen ServicesCitizen Services

PermitsPermitsInspectionsInspectionsHistorical Historical BldgsBldgs

UEZUEZBusinessBusinessDevelopment Development

Crime responseCrime responseCrime trackingCrime tracking

Voter RegistrationVoter RegistrationSenior CitizenSenior CitizenImmunization programsImmunization programs

BuildingBuildingEngineeringEngineering

Economic Dev.Economic Dev.

Housing, Land Use & Zoning, Housing, Land Use & Zoning, Open SpaceOpen SpaceSchools, Day CareSchools, Day Care

PlanningPlanning PolicePolice

Fire responseFire responseInspectionInspectionHazMatHazMatFire DistrictsFire Districts

FireFire

Uses for Parcel/Address DataTransportationTransportationInfrastructureInfrastructure

Mgmt.Mgmt.

•Owner

•Address

•Land usage/zoning

•Sales

•Property Value

DIGITAL TAX MAP

COMMITTEE

• Majority of parcel data is not mathematically constructed based upon a uniform standard

• Created from individual tax map sheets that were not tied to a defined coordinate system

• Data from separate sheets warped to fit

•Current process often involves editing tax maps on paper, then reproducing the same changes in the GIS data.

•Maintaining two products through separate processes is needless duplication of effort

•Goal with digital tax maps is a seamless flow of information from the tax map into GIS and other information systems

Read and follow the Division of Taxation’s Rules •N.J.A.C. 18:23A, revised, effective June 4, 2007.

DIGITAL TAX MAP

COMMITTEE

Appointment of a New Jersey Licensed Professional Land Surveyor

• N.J.A.C. 13:40-5.1(k) requires that Tax assessment maps must be prepared by a New Jersey LicensedProfessional Land Surveyor.

• Recommended appointment longer than 1-year term, 3-years term is suggested.

• Surveyor and Tax Assessor develop a working relationship and ease of sharing information on atimely basis.

DIGITAL TAX MAP

COMMITTEE

Information such as a copy of the MOD IV, deeds, subdivisions, street vacations should be supplied to the land surveyor as they occur and revisions made when time allows.

DIGITAL TAX MAP

COMMITTEE

Use of Coordinate Geometry (COGO) for creating digital tax maps.

• DO NOT SCAN THE EXISTING TAX MAP!DO NOT SCAN THE EXISTING TAX MAP!

• Provides for a geo-referenced seamless tax map• Provides for layering conventions compliant with aNational and Statewide standard.

• Will ultimately provide for a statewide seamless tax mapDIGITAL TAX MAP

COMMITTEE

The Tax Map Backbone is established using: • New Jersey State Plane Coordinate System Control forthe base network (GPS Control)

• Current and existing Orthophotography• Photogrammetry• Deeds of Record• Road Returns• Filed Maps such as:• Subdivision Plats• Highway Right-of-Way plans• Railroad Right-of-Way plans• Right-of-Way Vacation plans• Easement plans• Easements

DIGITAL TAX MAP

COMMITTEE

DIGITAL TAX MAP

COMMITTEE

DIGITAL TAX MAP

COMMITTEE

DIGITAL TAX MAP

COMMITTEE

Digital Tax Maps – Ease of Maintenance

•Digital or COGO drafting is faster than hand drafting and does not require erasing the original, thereby preserving the historical map.

•Digital Seamless Tax Maps can be viewed via computer as a seamless map or in sheet layout as paper/mylar maps.

•Provides for a quick conversion to a seamless parcel layer for GIS.

DIGITAL TAX MAP

COMMITTEE

Time for insertion from digital subdivision submission: 1 staff hour. Manual erasing mylar and hand drafting onto tax map sheet, estimated: 12 staff hours.

SAVINGS = 11 staff hours for one revision of a total of 108 new lots.

DIGITAL TAX MAP

COMMITTEE

• Keep pace with updating data as it is discovered, as then information will beavailable when needed

• Visual information is easily digested by thetaxpayer, courts, and public

• Less time in litigation = $$$ SAVINGS

• The municipal land surveyor is the key to creating these reports

DIGITAL TAX MAP

COMMITTEE

• Advantages of Digital Tax Maps• NJ Digital Tax Maps - CAD Standards • NJ Digital Tax Maps - CAD Layer Template June 2008• NJ Digital Tax Map key sheet – beta version• NJ Digital Tax Map detail sheet – beta version• Examples of Municipal Uses of Tax Map, Parcel andTax Assessor Data

• CAD Tax Map Best Practices• Sample municipal ordinance for digital submission of

subdivisions• Sample RFP for a digital tax map• League of Municipalities Presentation on Digital

Tax Maps

DIGITAL TAX MAP

COMMITTEE

DIGITAL TAX MAP

COMMITTEE

https://njgin.state.nj.us/NJ_NJGINExplorer/ jviewer.jsp?pg=digital_tax_map

OR•Go to njgin.state.nj.usnjgin.state.nj.us•Click on ResourcesResources•Click on Digital Tax Map and SubdivisionDigital Tax Map and Subdivision

BEWARE OFBEWARE OFDATUMS!DATUMS!

DIGITAL TAX MAP

COMMITTEE

Problems when converting State Plane - Latitude & Longitude

What was the source datum?

DATUM

• A system of values that serves as a reference or base for measurements of position.

• A horizontal datum (example: North American Datum of 1983, or NAD 83) is a reference for x,y measurements.

• A vertical datum (example: North American Vertical Datum 1988, or NAVD 88) is a level surface of reference for measurements of elevation. “Mean sea level” is not specific enough for survey measurements.

METADATA

• Information about the content of a data set, for example the methods used for creating the data, when it was created, by whom, accuracy, etc.

• Documentation.

NAD 83 (North Atlantic Datum, Adjustment of 1983) vs. NAD 27 (North American Datum, Adjustment of 1927.

NAD 83 (North Atlantic Datum, Adjustment of 1983) vs. NAD 27 (North American Datum, Adjustment of 1927.

NAD 27 (North American Datum, Adjustment of 1927 vs. NAD 83 (North Atlantic Datum, Adjustment of 1983) .

The NAD 27 is a horizontal datum for the continental United States based on the Clarke ellipsoid of 1866 (Clarke 1866). The fixed datum reference point is located at Meades Ranch, Kansas. The longitude origin of NAD 27 is the Greenwich Meridian with a south azimuth orientation. The original network adjustment used 25,000 stations. The relative precision between initial point monuments of NAD 27 is by definition 1:100,000, but coordinates on any given monument in the network contain errors of varying degrees. As a result, relative accuracies between points on NAD 27 may be far less than the nominal 1:100,000. The reference units for NAD 27 are US Survey Feet. This datum is no longer supported by NOAA/NOS/NGS. Approximate conversions of points on NAD 27 to NAD 83 (1986) may be performed using the NADCON model. Since NAD 27 contains error approaching 10m, transforming highly accurate GPS observations to this antiquated reference system is not the best approach.

NAD 27 (North American Datum, Adjustment of 1927 vs. NAD 83 (North Atlantic Datum, Adjustment of 1983) .

While The North American Datum of 1983 (NAD 83) is a 3-D reference system it also serves as the horizontal control datum for the United States, Canada, Greenland and Central America using the Geodetic Reference System 1980 (GRS 80) ellipsoid, an earth-centered reference ellipsoid. The NAD 83 was readjusted in 1986 by the NOAA/NOS/NGS and is referred to as NAD 83 ((1986)). While NAD 83 (1986) is 3-D in scope, NOAA/NOS/NGS adopted only horizontal coordinates (latitude and longitude) for over 99% of the approximately 250,000 stations to readjust the national network. The longitude origin of NAD 83 is the Greenwich Meridian with a north azimuth orientation. NAD 83 (1986) coordinates have an average relative precision of 1:300,000. With increasingly more accurate uses of GPS, the errors and misalignments in NAD 83 (1986) became more noticeable (approached 1m), hence refinements such as High Accuracy Reference Network (HARN) and Continuously Operating Reference Stations (CORS) have been made to correct the inconsistencies in NAD 83(1986).

NAD 83 (North Atlantic Datum, Adjustment of 1983)NJSPCS – (NEW JERSEY STATE PLANE COORDINATE SYSTEM)

NAD 83 (North Atlantic Datum, Adjustment of 1983)NJSPCS – (NEW JERSEY STATE PLANE COORDINATE SYSTEM)NATIONAL SPATIAL REFERENCE SYSTEM

National Geodetic Reference System

The National Geodetic Reference System (NGRS) exists as a collection of discreet geodetic elements. Horizontal positions (latitude and longitude, State Plane Coordinates) referenced to a two-dimensional datum, the North American Datum of 1983 (NAD 83), and elevations (Helmert orthometric heights) referenced to a one- dimensional datum, the North American Vertical Datum of 1988 (NAVD 88) define the major components of the NGRS.

Both datums are the latest definitions of systems that began with the first geodetic surveys conducted by the Survey of the Coast, founded in 1807 (later renamed the Coast Survey-1836, U. S. Coast and Geodetic Survey- 1878, and National Ocean Service-1970). NGS, a component of C&GS/NOS, is responsible for most of NOS' geodetic mission.

These geodetic systems were developed independently with little regard to being correlated. That is, a survey monument that provided accurate horizontal coordinates was not normally connected to the vertical network, nor were vertical points related to the horizontal reference network. Today (1994), the NGRS contains information on approximately 300,000 horizontal control points and 600,000 vertical control points.

David R. Doyle,Senior GeodesistNational Geodetic SurveyCoast and Geodetic Survey

National Spatial Reference System

To address the changing requirements for positional information, NGS began a strategic planning evaluation in 1992. Formally adopted in March 1994 (NGS 1994), this plan details, in a series of 15 strategic goals, the steps necessary to accomplish the transition from NGRS to NSRS.

A case can be made that the change to NSRS is simply a name change, and that the NGRS already incorporates the features necessary to support the integrity of the National Spatial Data Infrastructure. In part this is true. However, the term Geodetic has often been intimidating to many data users, implying a somewhat mystic science that almost no one understood. Changing the name to Spatial is intended to be more consistent with the needs of the public and should not require data users to run for their dictionaries to find out what the term means.

The change is not just cosmetic. It represents a fundamental change by NGS to understand the needs of geospatial data users, and to restructure its surveying operations, research and development activities, and data distribution, some of which have changed only slightly in over 180 years. These changes include development of the Federal Base Network (FBN), Cooperative Base Network (CBN), User Densification Network, Continuously Operating Reference Stations (CORS), GPS Orbits, a high accuracy geoid, and improved data access.

David R. Doyle,Senior GeodesistNational Geodetic SurveyCoast and Geodetic Survey

NAD 83 (North Atlantic Datum, Adjustment of 1983)NJSPCS – (NEW JERSEY STATE PLANE COORDINATE SYSTEM)NATIONAL SPATIAL REFERENCE SYSTEMGROUND vs. GRID

GROUND vs. GRID

NAD 83 (North Atlantic Datum, Adjustment of 1983)NJSPCS – (NEW JERSEY STATE PLANE COORDINATE SYSTEM)NATIONAL SPATIAL REFERENCE SYSTEMGROUND vs. GRIDCENTROID

CENTROID

NAD 83 (North Atlantic Datum, Adjustment of 1983)NJSPCS – (NEW JERSEY STATE PLANE COORDINATE SYSTEM)NATIONAL SPATIAL REFERENCE SYSTEMGROUND vs. GRIDCENTROIDCORS (CONSTANTLY OPERATING REFERENCE STATIONS)

NJIT Reference Station Network

Constantly Operating Reference SystemsReal time broadcast correction signal

NAD 83 (North Atlantic Datum, Adjustment of 1983)NJSPCS – (NEW JERSEY STATE PLANE COORDINATE SYSTEM)NATIONAL SPATIAL REFERENCE SYSTEMGROUND vs. GRIDCENTROIDCORS (CONSTANTLY OPERATING REFERENCE STATIONS)UTM

Universal Transverse Mercator

SEA LEVEL DATUM (NGVD-29)

(a/k/a NATIONAL GEODETIC VERTICLE DATUM, ADJUSTMENT OF 1929)

"The National Geodetic Vertical Datum of 1929: The name, after May 10, 1973, of (the) Sea Level Datum of 1929." (vertical control datum established for vertical control in the United States by the general adjustment of 1929.”

“Mean sea level was held fixed at the sites of 26 tide gauges, 21 in the U.S.A. and 5 in Canada. The datum is defined by the observed heights of mean sea level at the 26 tide gauges and by the set of elevations of all bench marks resulting from the adjustment. A total of 106,724 km of leveling was involved, constituting 246 closed circuits and 25 circuits at sea level.”

The datum (was) not mean sea lever, the geoid, or any other equipotential surface. Therefore is was renamed, in 1973, the National Geodetic Vertical Datum of 1929.”

DATUMS-VERTICAL

SEA LEVEL DATUM (NGVD-29)

(a/k/a NATIONAL GEODETIC VERTICAL DATUM, ADJUSTMENT OF 1929)

NAVD 88 (North Atlantic Vertical Datum, Adjustment of 1988)

DATUMS-VERTICAL

NAVD 88 (North Atlantic Vertical Datum, Adjustment of 1988)

The North American Vertical Datum of 1988 (NAVD 88) is the vertical control datum established in 1991 by the minimum-constraint adjustment of the Canadian-Mexican-U.S. leveling observations. It held fixed the height of the primary tidal bench mark, referenced to the new International Great Lakes Datum of 1985 local mean sea level height value, at Father Point/Rimouski, Quebec, Canada. Additional tidal bench mark elevations were not used due to the demonstrated variations in sea surface topography, i.e., the fact that mean sea level is not the same equipotential surface at all tidal bench marks.

DATUMS-VERTICAL

TIDAL

DATUMS-VERTICAL

TIDAL

MEAN SEA LEVEL• The arithmetic mean of hourly heights observed over the

National Tidal Datum Epoch.

DATUMS-VERTICAL

TIDAL

MEAN SEA LEVEL

MEAN HIGHER HIGH WATER • The average of the higher high water height of each tidal day

observed over the National Tidal Datum Epoch.

DATUMS-VERTICAL

TIDAL

MEAN SEA LEVEL

MEAN HIGHER HIGH WATER

MEAN HIGH WATER /MEAN HIGH WATER LINE• MEAN HIGH WATER

– The average of all the high water heights observed over the National Tidal Datum Epoch (19 years). For stations with shorter series, comparison of simultaneous observations with a control tide station is made in order to derive the equivalent datum of the National Tidal Datum Epoch.

DATUMS-VERTICAL

TIDAL

MEAN HIGH WATER /MEAN HIGH WATER LINE

Mean High Water Line/Mark (MHWL)• The line on the shore in tidal areas established by the

fluctuations of water and indicated by physical characteristics such as a clear, natural line impressed on the bank, shelving, changes in the character of soil, destruction of terrestrial vegetation, the presence of litter and debris, or other appropriate means that consider the characteristics of the surrounding area.

DATUMS-VERTICAL

TIDAL

MEAN SEA LEVEL

MEAN HIGHER HIGH WATER

MEAN HIGH WATER LEVEL

MEAN TIDE LEVEL• The arithmetic mean of mean high water and mean low water.

DATUMS-VERTICAL

TIDAL

MEAN SEA LEVEL

MEAN HIGHER HIGH WATER

MEAN HIGH WATER LEVEL

MEAN TIDE LEVEL

MEAN LOW WATER • The average of all the low water heights observed over the

National Tidal Datum Epoch.

DATUMS-VERTICAL

TIDAL

MEAN SEA LEVEL

MEAN HIGHER HIGH WATER

MEAN HIGH WATER LEVEL

MEAN TIDE LEVEL

MEAN LOW WATER LEVEL

MEAN LOWER LOW WATER LEVEL• The average of the lower low water height of each tidal day

observed over the National Tidal Datum Epoch.

DATUMS-VERTICAL

TIDAL

MEAN SEA LEVEL

MEAN HIGHER HIGH WATER

MEAN HIGH WATER LEVEL

MEAN TIDE LEVEL

MEAN LOW WATER

MEAN LOWER LOW WATER

SPRING HIGH TIDE LINE• Same as Mean High Higher Water

DATUMS-VERTICAL

T I D A L D A T U M S

Tidal datums at THE BATTERY, NEW YORK HARBOR based on:

LENGTH OF SERIES: 19 YEARSTIME PERIOD: January 1983 - December 2001TIDAL EPOCH: 1983-2001CONTROL TIDE STATION:

Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:

HIGHEST OBSERVED WATER LEVEL (09/12/1960) = 3.052MEAN HIGHER HIGH WATER (MHHW) = 1.541MEAN HIGH WATER (MHW) = 1.443NORTH AMERICAN VERTICAL DATUM-1988 (NAVD) = 0.847MEAN SEA LEVEL (MSL) = 0.783MEAN TIDE LEVEL (MTL) = 0.753MEAN LOW WATER (MLW) = 0.063MEAN LOWER LOW WATER (MLLW) = 0.000LOWEST OBSERVED WATER LEVEL (02/02/1976) = -1.307

Bench Mark Elevation Information In METERS above:

Stamping or Designation MLLW MHW

NO 7 1975 4.468 3.025NO 3 4.276 2.833NO 6 1975 3.556 2.113BM 5.720 4.277851 8750 TIDAL 749 5.690 4.247R 340 1952 2.847 1.404

TIDAL

MEAN SEA LEVEL

MEAN HIGH WATER LEVEL

MEAN TIDE LEVEL

MEAN LOW WATER LEVEL

MEAN LOWER LOW WATER LEVEL

SPRING HIGH TIDE LINE

HIGH TIDE LINE

DATUMS-VERTICAL

High Tide Line (HTL):

The line of intersection of the land with the water's surface at the maximum height reached by a rising tide. The high tide line may be determined, in the absence of actual data, by a line of oil or scum along shore objects, a more or less continuous deposit of fine shell or debris on the foreshore or berm, other physical markings or characteristics, vegetation lines, tidal gages, or other suitable means that delineate the general height reached by a rising tide. The line encompasses spring high tides and other tides that occur with periodic frequency but does not include storm surges in which there is a departure from the normal or predicted reach of the tide due to the piling up of water against a coast by strong winds such as those accompanying a hurricane or other intense storm.

DATUMS-VERTICAL

Datums and Boundaries

GEOID MODELS

1999

2003

2006

2008

2012?

GEOID MODELS

The geoid is a specified equipotential surface, defined in the Earth's gravity field, which best fits, in a least squares sense, global mean sea level (MSL). It is undulate, smooth and continuous, fictitiously extending under the continents at the same level, and by definition perpendicular at any point to the direction of gravity. It should be noted that due to effects such as atmospheric pressure, temperature, prevailing winds and currents, and salinity variations, MSL can depart from an equipotential surface by a meter or more.

The geoid is a complex, physically based surface, and can vary by up to 100 meters in height from a geocentric ellipsoid. Thus, national and regional vertical datums around the world, which are locally tied to MSL, are significantly different from one another when considered on a global basis. In addition, due to the realization and orthometric height approximations of various vertical datums, other departures at the meter level or more will be found when comparing elevations to a global geoid reference.

GEOID MODELS

Suggested Note:

DATUM:NORTH AMERICAN VERTICAL DATUM ADJUSTMENT OF 1988-GEOID 03

GEOID MODELSGRAVITY

GRAVITY

What information is needed for NGS to provide a gravity prediction? For a Laplace correction?

Gravity prediction: NGS provides interpolated gravity values at specified positions based on observed gravity in its Integrated Data Base. These values are referenced to the International Standardization Net 1971, which is an absolute gravity datum. NGS needs the geographic position (i.e., latitude and longitude) of the site of prediction. The topographic (i.e., mean sea level) height at this position is very useful and improves the accuracy of interpolation, but is not mandatory for interpolation. Contact the NGS Information Center [Call (301) 713-3242, or e-mail iinfo center] with the positional information and they will respond to the request for an interpolated gravity value.

NGS also provides an interactive capability to compute predicted gravity at a single point.