FIELD		TYPE/WIDTH		DEFINITION
L_BASE		C / 3		Base map type code
L_ACC_EST		I / 4		Location accuracy estimate measurement
L_TYPE		C / 4		Location type code
L_METH		C / 4		Location method code
L_SRC_1		C / 30		Primary source material code
L_SRC_2		C / 30		Secondary source material code
L_SRC_3		C / 30		Tertiary source material code
L_DATE		C / 8		Date of automation

L_BASE (Location Base Map)
The standard MassGIS base map is the 1:5,000 digital orthophotography (DOQ).  Point data development at DEP should whenever possible conform to the 1:5,000 standard.  Since DEP has significant historical data developed at smaller scales (1:24,000 and 1:25,000), it is important that base scale be documented.

The L_BASE field contains a code that represents both the type of base map and/or the technique used for digitizing the location. (See Appendix A for a current set of DEP PDDS location base map codes).

L_ACC_EST (Location Accuracy Estimate)
Horizontal accuracy refers to the quantitative measurement of the deviation from a coordinate position to the actual position (on the ground) that the coordinate represents.  The DEP’s horizontal accuracy goal for point locations is +/-16.4 feet (approx. 5m).  This goal reflects the accuracy capabilities of the DEP’s GeoExplorer (GPS) receivers, which under optimal mapping conditions are capable of providing horizontal accuracy typically in the order of 2-5 meters.  The DEP’s horizontal accuracy goal exceeds the +/-25 meter (approx. 82ft) horizontal accuracy goal recommended by the EPA’s Locational Accuracy Task Force (LATF).  Like the EPA’s recommended accuracy goal (+/-25m), it is important to remember that DEP’s accuracy goal (+/-16.4 ft) is simply a goal and not a standard.  Most DEP point locations are estimated to be within +/-100 feet (30.5m), and the coarsest allowable horizontal accuracy for DEP production data is  +/-1,000 feet (305m).

The L_ACC_EST field contains an integer code representing the estimated horizontal accuracy of the location in feet, according to the data developer.  (See Appendix B for a current list of DEP PDDS location accuracy estimate codes.)

L_TYPE (Location Type)
The location type (L_TYPE) field contains a spatial reference code, indicating what the point represents.
(See Appendix C for supported location type codes.)

L_METH (Location Method)
The location method (L_METH) field contains an alphanumeric code defining the method used to locate the feature.  The location method is determined by the primary source used.
(See Appendix D for supported location method codes.)
       
L_SRC_1 (Primary Location Source)
The L_SRC_1 field contains a code indicating the primary source material used to locate the feature.  Relevant date information should be recorded in L_SRC_1_DATE.  (See Appendix E for supported location source codes.)

L_SRC_2 (Secondary Location Source)
The L_SRC_2 field contains a code that indicates the secondary source material used to locate the feature. Relevant date information should be recorded in L_SRC_1_DATE.  (See Appendix E for supported location source codes.)

L_SRC_3 (Tertiary Location Source)
The L_SRC_3 field contains a code that indicates any tertiary source material used to locate the feature. Relevant date information should be recorded in L_SRC_1_DATE.  (See Appendix E: for supported location source codes.)

L_DATE (Automation Date)
The L_DATE field contains the date the feature was located/automated in GIS.  The date of automation is automatically populated through the PDT.  When using an automation methodology other than the PDT, automation date should be entered as follows: 20010403 for April 3, 2001.  When editing locations outside of the PDT the L_DATE should be modified to reflect the date the point was last edited.

L_BASE (Location Base Map) Codes

DEP PDDS CODE		DEFINITION
DOQ		Digital orthophoto base map (DOQ)
DTQ		USGS digital topographic quadrangle (DTQ)
DVB		Digital vector base (DVB) map
PTQ		USGS paper topographic quadrangle (PTQ) base map or stable mylar overlay compiled from USGS topographic quad using traditional tablet digitizing technique
NA		Not applicable (NA), automation based on address match technique or Coordinate input from source such as external database or GPS.
UNK		Unknown

Appendix B:

L_ACC_EST (Location Accuracy Estimate) Codes 

DEP PDDS CODE		DEFINITION
16		Estimated horizontal accuracy is 0 - +/-16 feet
100		Estimated horizontal accuracy is +/-16 - +/-100 feet
500		Estimated horizontal accuracy is +/-100 - +/-500 feet
1000		Estimated horizontal accuracy is +/-500 - +/-1,000 feet
9999		Estimated horizontal accuracy is greater than 1,000 feet
0		Horizontal accuracy estimate unknown

Appendix C:

L_TYPE (Location Type) Codes

L_TYPE		L_TYPE DEFINITION		FEATURE_TYPE
AA		Perimeter of assigned area		POLYGON
AB		Administrative building		POINT
AMS		Air monitoring station		POINT
ARV		Air Release Vent		POINT
CA		Center of site investigation activity		POINT
CB		Center of a building footprint positively associated with the facility/site		POINT
CB2		Center of a building footprint, NOT positively associated with the facility/site		POINT
CF		Center of a facility		POINT
CL		Center of property lot or parcel associated with a facility/site address		POINT
CS		Center of site or area of known contamination		POINT
CT		Center of individual tank or cluster of tanks (AST or UST)		POINT
CWA		Center of Waste (approximate/presumed)		POINT
CWK		Center of Waste (known)		POINT
EL		Estimated location		POINT
EWA		Extent of Waste (approximate/presumed)		POLYGON
EWK		Extent of Waste (known)		POLYGON
FR		Center of Firing Range (rod & gun clubs)		POINT
FDF		Facility/Site Entrance (Freight)		POINT
FDG		Facility/Site Entrance (General)		POINT
FDP		Facility/Site Entrance (Personnel)		POINT
FDU		Front door or main entrance to a facility/site (Unspecified)		POINT
FEN		Fence-Line Visible on Source Map/Image		POLYGON
GW		Water supply well		POINT
INC		Incinerator		POINT
IW		Irrigation well		POINT
LAG		Lagoon or settling pond		POINT
MW		Monitoring well		POINT
OTH		Other		POINT, POLYGON
PB		Parcel Boundary		POLYGON
PD		Point of discharge (NPDES)		POINT
PH		Pump house associated with PWS well		POINT
PR		Point of release (Ch 21E)		POINT
RES		Center of PWS reservoir		POINT
RW		Center of receiving water body		POINT
SC		Source of contamination		POINT
SPR		PWS spring		POINT
ST		Emissions stack		POINT
SW		PWS surface water intake		POINT
TF		Center of trap field (rod & gun clubs)		POINT
UNK		Unknown		POINT
WF		PWS Well field		POINT
WMS		Water monitoring station or sampling point		POINT
WP		PWS wellfield well point (TWF)		POINT

Appendix D:

L_METH (Location Method) Codes 

L_METH		L_METH DEFINITION
AM_1		Address matched to number and street or parcel
AM_2		Address matched to nearest intersection
AM_3		Address matched to midpoint of street segment centerline
AM_4		Address Matched to Zipcode Centroid
AM_5		Address Matched to Town Centroid
DD_1		Location snapped to point feature in an existing digital data source
DD_2		Location snapped to the centroid of an existing area digital data source
GP_1		GPS Survey Grade Carrier Phase Signal Data
GP_2		GPS Coarse Acquisition Code:  DGPS (1-5 meter accuracy)
GP_3		GPS Coarse Acquisition Code:  DGPS (sub-meter accuracy)
GP_4		GPS Coarse Acquisition Code: Uncorrected, positions averaged
GP_5		GPS Coarse Acquisition Code: Uncorrected, single position
GP_6		GPS: Unspecified Device, DGPS Unknown
GR_1		Digitized from Georeferenced map, registered with survey grade coordinates
GR_2		Digitized from Georeferenced map, registered with DGPS (2-5 meter) coordinates
GR_3		Digitized from Georeferenced map, registered using digital orthophoto
DDS		Interpolation - Digital Map Source
MAP		Interpolation - Map
MSS		Interpolation - MSS
OTH		Interpolation - Other
PHO		Interpolation - Photo
SAT		Interpolation - Satellite
SPOT		Interpolation - SPOT
TM		Interpolation - TM
XY_1		Coordinate pair derived from traditional survey techniques
XY_2		Coordinate pair unverified or reported by regulated community, includes undocumented coordinate data
UNK		Unknown

Appendix E:

L_SRC_(N)  (Location Source) Codes

L_SRC_(N)		L_SRC_(N) DEFINITION
DB_BOH		Massachusetts Board of Health
DB_EPICS		DEP Environmental Protection Integrated Computer System
DB_EPA		United States Environmental Protection Agency - System Unspecified
DB_DFS		Massachusetts Department of Fire Services (DFS)
DB_DOE		Massachusetts Department of Education
DB_SSEIS		DEP BWP Stationary Source Emission Inventory System
DB_RCRIS		EPA Resource Conservation and Recovery Information System
DB_WMA		DEP Water Management Act
DB_WPP		DEP Water Permitting Program Database
DB_OTH		Other Database Source
DD_21E		DEP BWSC Chapter 21E Tier Classified Oil or Hazardous Materials datalayer
DD_BAS		MassGIS watershed/basin data
DD_FAC		DEP BWP Regulated Facilities datalayer
DD_GDT		Geographic Data Technology (GDT) streets Geocoding datalayer
DD_GWP		DEP Permitted Discharge to Groundwater datalayer
DD_HOSP		MassGIS Hospitals and Emergency Room Facilities datalayer
DD_LU		MassGIS Land Use datalayer
DD_MMR		Massachusetts Military Reservation
DD_NPDES		DEP NPDES datalayer
DD_NPL		US EPA National Priority List datalayer
DD_OS		MassGIS Open Space datalayer
DD_PAR		Digital Parcel Data
DD_PWS		DEP Public Water Supply datalayer
DD_SCHL		Schools datalayer
DD_SW		DEP BWP Solid Waste Facilities datalayer
DD_SWAP		Contracted data developed through DEP SWAP
DD_TIGER		US Census Bureau TIGER Line Files
DD_UNK		Unknown
DD_UST		DEP Underground Storage Tanks datalayer
DD_OTH		Other Digital Data Source
MS_LMTQ		Locus map based on USGS topographic quadrangle map
MS_LMST		Locus map based on street information (ex. Street Atlas)
MS_LMOT		Locus map other (ex. Trail map)
MS_MCP		DEP MCP Site Scoring Map
MS_PIM		DEP Pre-inspection Map
MS_SITE		Detailed Site plan or map
MS_SKCH		Hand sketched map
MS_SURV		Survey grade map of site derived from traditional survey techniques
MS_SWAP		DEP SWAP Map
MS_TAX		Tax assessment map
MS_USGS		USGS topographic quadrangle map
MS_WWW		Internet map source (use L_COMM to record web URL)
MS_OTH		Other Map Source
AP_CIR		DWW Color Infrared photography 1:12,000
AP_DOQ		MassGIS 1:5,000 digital orthophotography
AP_GE		General Electric (GW) Project
AP_PC		Pictometry Community Oblique
AP_PN		Pictometry Neighborhood Oblique
DS_GPS		GPS Data Sheet
FMSR		Field Measurement (tape and compass bearings)
KNOW		Located by DEP staff through knowledge gained in the course of their professional activities
OTH		Other
TEXT		Textual information
UNK		Source Unknown
VERB		Verbal information
WWW		Website Information
EDEP		Submitted via eDEP Application, Source Unknown
AP		Other aerial photo source
MSS		Multi Spectral Signature Image
SAT		Other Satellite Image
SPOT		SPOT Corporation Image
SV		Site visited for the purpose of field verification and/or site inspection
TM		Thematic Mapper Image

Last Updated 3/9/2006
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