Metro Tax lots Metadata

Tax lots - Shapefile version
	1. Identification Information 2. Data Quality Information 3. Spatial Data Organization Information 4. Spatial Reference Information 5. Entity and Attribute Information 6. Distribution Information 7. Metadata Reference Information

IDENTIFICATION INFORMATION

1.1

Citation

Originator

Metro Data Resource Center

Tax lots, right-of-way outlines and tax account numbers as represented on county tax assessor hard copy maps. Each tax lot is a polygon with an associated tax lot number which is the "hook" to the county tax assessor's tabular data base. Selected items from each County Assessor's file are included. In Clackamas and Washington counties, the tax lot spatial features are maintained by the counties and delivered to Metro on a quarterly basis. The taxlots covering the City of Portland are maintained by the city and sent fo Metro quarterly. The remainder of Multnomah County is maintained by Metro.

Purpose

All data associated with the taxlot shape files are compiled by Metro from existing records created and maintained by county Assessment and Taxation offices. Care should be taken in the use and interpretation of these data. Not all columns are fully populated by the assessor. For example, the landuse and prop_code columns are useful for producing generalized land-use maps, but are not considered reliable for parcel specific applications. Field verification has not been done.

Supplemental information

ArcView legends: Landval.avl - draws land value in 4 classes
Bldgval.avl - draws building value in 4 classes
Totalval.avl - draws total value in 4 classes
bldgsqft.avl - draws building sq. ft. in 4 classes
Yearblt.avl - draws year built in 4 classes
Landuse.avl - shades each land use in a different color
The ArcInfo coverage also includes polygons which are not taxlots, e.g. streets, railroad rights-of-way and water bodies. The coverages are tiled by section. Coverages include line attributes (not available as shapefile or SDE layer).

1.3

Time period of content

Maintenance/update frequency

Clackamas, Multnomah and Washington counties in Oregon.

West bounding coordinate

-123.47121656

East bounding coordinate

-121.65053671

North bounding coordinate

45.82618832

South bounding coordinate

44.85462409

1.6

Keywords

Theme keyword thesaurus

None

Theme keyword

Taxlots, tax lots, parcels, assessor, cadastral

Place keyword thesaurus

None

Place keyword

Portland, Clackamas County, Multnomah County, Washington County, Oregon

These data are sold under the agreement that the user may use the data in its business activity and for no other purpose whatsoever. User shall not allow access to the data by any other person or organization, unless authorized in writing by the Metro DRC or, if the other party is a contractor providing services to a government requiring usage of the data in order to provide contractual services.
User shall not duplicate the data except for the following:
(1) User may make one backup copy of the data, and
(2) User may translate the data into other formats and/or media.
For full product purchase agreement that accompanies these data, please see http://storefront.metro-region.org/drc/rlislite/subscribe/license.cfm

1.10

Browse graphic

Browse graphic file name

taxlot.gif

Browse graphic file description

Sample tax lot plot shaded by assessor's building value. The street names are also shown.

Browse graphic file type

GIF

1.13

Native data set environment

Shape file: taxlots.shp
SDE layer: taxlots.taxlots
Cover name: $countyname/section/tl or library countyname.tl
Software/hardware: ArcInfo 8.1 on NT workstation.
ArcSDE 8.1 on Compaq Alpha 4100. Tru64 5.0 OS.

[Top of Page]

DATA QUALITY INFORMATION

2.4

Horizontal positional accuracy

Street center lines were digitized from aerial orthophotography at +/- 10 feet accuracy. Tax lots were fit to the street centerlines. Beaverton, Oregon City and Tigard planning areas were improved to +/- 5 feet accuracy. Multnomah County was created with coordinate geometry using better control.

Portland General Electric (PGE) purchased aerial orthophotography with 10 foot horizontal control and digitized street center lines, tax lots and street names. This layer was produced on a CAD system as a visual background to their electrical system.

Metro converted the PGE line work to polygons and added tax account numbers. David Evans and Associates was contractor. Beaverton, Oregon City and Tigard planning areas were improved to +/- 5 feet accuracy. Oregon Dept. of Revenue and Multnomah County Assessor provided CAD drawings of the area east of 42nd Ave. which had been entered using coordinate geometry and existing control from the cities and county. This original RLIS dataset contained 553 sections.

Metro converted 436 rural sections to polygon coverages and added tax account numbers. David Evans and Associates was contractor. Tax assessor hard copy maps were scanned and registered to PGE base maps.

Washington Co. rural taxlot linework created by Washington Co. using assessor maps.

Washington County began maintaining this layer within their boundaries.

Metro converted the coverage from NAD27 to NAD83 and from single to double precision.

Clackamas County began maintaining this layer within their boundaries.

Multnomah Co. rural taxlot linework created by Metro using 1:24000 USGS quad for control.

Oregon Dept. of Revenue and Multnomah County Assessor provided tax lot CAD drawings of the remaining areas of the city of Portland. This data was entered using coordinate geometry and existing control. The city of Portland converted the CAD drawings to ARC/INFO format and furnished the information to Metro.

A major upgrade was completed in Multnomah County. The taxlots for Portland were re-mapped and updated. The horizontal positional accuracy was spatially corrected.
Columns storing X and Y coordinates of each taxlot were added, mainly for use by programmers.

Clackamas County is gradually improving the horizontal ground control of the map by registering the map to the 1996 Spencer B. Gross digital orthophotography. The photography has ground control of +/- 5 feet.

In Multnomah County, the "TLID" field was changed to be the "state ID number" instead of the account number (R number). This made Multnomah County consistent with the other two counties. In cases where the state ID number was not available, the R number was supplied. Since the state ID number is wider in Multnomah County, the TLID field was changed to 15 characters wide instead of 12.
The Multnomah County portion was projected to NAD83/91 projection (also known as HPGN).

A field called "Rno" was added to the taxlots shapefile. Earlier the Multnomah County "R number" was used in the "Tlid" field. The "R number" is now in its own field for those users who still need it.

This layer was reprojected to the NAD83/91 projection (also known as HPGN) as part of a conversion of all RLIS map layers.

In Washington County, the technique used to populate OWNER2, OWNER3 and OWNERADDR was improved. Previously the address could appear in OWNER2, OWNER3 or OWNERADDR (depending on the first available field). Now all the address information is in OWNERADDR.

Multnomah County Assessment and Taxation updated their computer system and are now using a new format for the tax lot identifier (TLID). Since the beginning of RLIS Lite, Metro has used the county's format for taxlot number, so we converted to the new 16-character number used by the county.
EXAMPLE: (^ represents a space). 1S2E06AB^^^00100. If the quarter section or quarter-quarter section letters are not used, a space is used as a place holder. There are three additional spaces following the quarter-quarter section letter. The 5-digit tax lot number uses leading zeros as place holders if the number is less than 10000.
Landuse data for Multnomah County was extracted from a new field, and may look slightly different than previous releases.

The TLID format for Multnomah County was changed to be consistent with the format used by the Assessor. The 3 spaces between township, range, section and the taxlot id number was changed to 2 spaces and a hyphen.
Y2K issues required that the SALEDATE field be changed from a numeric field formatted YYMM to a character field formatted YYYYMM.

Projection information (.prj file), compatible with ArcGIS 8.1, was added to the layer.

Incorporated Clackamas County COGO-ed taxlot data for Lake Oswego and West Linn.

Add XML metadata compatible with ArcCatalog 8.1

Process date

20011031

[Top of Page]

SPATIAL DATA ORGANIZATION INFORMATION

3.2

Direct spatial reference method

Vector

3.3

Point and vector object information

SDTS point and vector object type

Polygon

Point and vector object count

473,114 - Polygon count (199811)

3.4

Raster object information

Raster object type

Row count

Column count

SPATIAL REFERENCE INFORMATION

4.1

Horizontal Coordinate System

Grid coordinate system name

State plane coordinate system 1983.

SPCS zone identifier

5076

Planar distance units

International feet

Horizontal datum name

North American Datum of 1983/1991 (HPGN)

[Top of Page]

ENTITY AND ATTRIBUTE INFORMATION

5.2

Overview description

Table Name	Column	Sample Domain Value	Definition
Taxlots.dbf	--	--	Tax lot attributes provided by the three county assessors.
	Area	--	Square footage of lot as calculated by the GIS
	Tlid	--	Tax lot account
	Rno	--	Record Number. Applies only to tax lots in Multnomah County.
	Ownersort	--	first five letters of owners name
	Owner1	--	owner's name line 1
	Owner2	--	owner's name line 2
	Owner3	--	owner's name line 3
	Owneraddr	--	owner's address
	Ownercity	--	owner's city
	Ownerzip	--	owner's ZIP code
	Sitestrno	--	site street number
	Siteaddr	--	site address
	Sitecity	--	Site city. Not populated in Washington County. Zip code is occasionally included.
	Landval	--	Assessed value of land
	Bldgval	--	Assessed value of building
	Totalval	--	Total assessed value (Landval + Bldgval)
	Bldgsqft	--	square footage of residential living area
	A_T_Acres	--	acreage of tax lot as shown in the County Assessor's database
	Yearbuilt	--	year structure was built
	Prop_code	--	property classification land use code; Usecode in Multnomah Co.
	Landuse	--	Land use category, derived from Prop_code
		AGR	Agriculture
		COM	Commercial
		FOR	Forest
		IND	Industrial
		MFR	Multi-family residential
		PUB	Public/semi-public
		RUR	Rural
		SFR	Single family residential
		VAC	Undeveloped
	Taxcode	--	county tax code (levy code in Multnomah County)
	Saledate	--	date of the most recent sale of the property (recording)
	Saleprice	--	price of the most recent sale of the property
	County	--	County abbreviation
		C	Clackamas County
		M	Multnomah County
		W	Washington County