Overview
Location Documentation Table Structure
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
Description of Items
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 codesL_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 codesL_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.
Appendix A:
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 AM Address-matched location 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 FD Approximate location of front door or main entrance to a facility/site 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 IN Interpolation based on primary source material (L_SRC_1) 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
Items Record Info
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_ESRI ESRI Data and Maps media 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 or OTHER 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