Provider guide and directory
Utility Mapping Services
Utility mapping services combine evidence about underground and above-ground utilities with spatial capture and a defined deliverable. Providers may collect GPR and electromagnetic locating results, visible structures, records, GPS or GNSS positions, survey control, and attribution notes, then organize the information in GIS, CAD, plan sheets, or another agreed format. A map is only as reliable as its source evidence, positioning method, quality controls, and stated limitations.
Utility locating vs. utility mapping
Locating develops field evidence about where a utility may run. Mapping records selected evidence in a coordinate system and packages it for a defined use. Painted marks alone are not a durable map, and a GPS point does not improve the quality of an unsupported utility interpretation.
| Stage | Primary task | Typical output |
|---|---|---|
| Records review | Compile plans, owner information, and known utility attributes | Source-indexed reference information with unresolved conflicts noted |
| Field locating | Use appropriate surface methods and visible features to develop alignments | Marks, flags, field notes, method records, and interpreted positions |
| Spatial capture | Record selected features using GPS, GNSS, survey, or another positioning method | Coordinates tied to a stated datum, control, and expected precision |
| Data delivery | Organize geometry, attributes, sources, and limitations | GIS, CAD, plan sheet, PDF, database, or client-specific format |
GPR, electromagnetic, records, and surface inputs
A mapping team may combine GPR utility locating, electromagnetic utility locating, surveyed visible structures, owner records, and other project evidence. Each mapped feature should retain its source and status so a record line is not mistaken for a field-designated line.
The scope should define utility types, horizontal and vertical information, area limits, inaccessible zones, attribution requirements, and whether test-hole or other physical verification data will be incorporated.
GPS, GNSS, GIS, CAD, and as-built deliverables
GPS and GNSS describe positioning technologies; GIS and CAD describe different data and drafting environments. A useful proposal names coordinate reference system, units, feature geometry, attributes, file format, symbology, naming, photos, metadata, and acceptance checks. If a licensed survey or certified engineering deliverable is required, that qualification must be stated separately.
GIS data
Feature geometry can be paired with utility type, source, date, method, confidence, owner, status, and attachments.
CAD and plan sheets
Layer standards, linework, annotation, scale, control, and base drawing requirements should be agreed before collection.
As-built information
Construction observations should be distinguished from interpreted existing-utility data and tied to the party responsible for capture.
Field-to-office traceability
Mapped features should preserve enough metadata to understand the original evidence and later updates.
Accuracy, completeness, and terminology limitations
Map precision, positional accuracy, utility-location confidence, and completeness are different properties. Precise coordinates can still represent an uncertain field interpretation. Tree cover, buildings, multipath, control quality, device setup, base maps, transformations, and operator procedures affect positioning.
Ordinary utility mapping is also not automatically subsurface utility engineering. Formal SUE includes an engineering process, defined quality levels, project risk management, surveying, and other requirements beyond producing a map.
Common questions
Frequently asked questions
What is included in a utility mapping deliverable?
It depends on the scope. Common elements include utility linework and structures, coordinates, source or method, collection date, depth observations, attributes, photos, unresolved areas, coordinate system, and limitations in GIS, CAD, PDF, or plan-sheet form.
Is GPS utility mapping survey-grade?
Not automatically. Device type, correction service, satellite conditions, control, procedures, and responsible professional determine the positioning quality. Request a stated accuracy specification and required survey qualification.
Is utility mapping the same as an as-built survey?
No. A map of interpreted existing utilities differs from documentation collected during or after construction. The source, responsible party, method, and status of every feature should be clear.
Can a provider convert field marks into GIS or CAD?
Yes, when spatial capture, coordinate system, attributes, file format, and quality controls are included in the scope. Photographing or sketching marks alone does not create a controlled geospatial dataset.
Technical references
Technical definitions and limitations on this page were checked against these primary government resources.
Provider discovery
Find utility mapping providers
Compare providers and confirm the field methods, positioning quality, data structure, professional qualifications, and deliverable format required by the project.
Capabilities to confirm
- Appropriate GPR, electromagnetic, records, and surface-feature workflows
- GPS, GNSS, survey-control, or other specified positioning capability
- GIS, CAD, plan-sheet, or client data-standard delivery
- Source, method, date, confidence, and limitation metadata
- Licensed survey or engineering involvement when required by scope or jurisdiction
1st Call Utility Locating is a Northern California private utility locating company specializing in identifying and documenting underground infrastructure before excavation, drilling, coring, construction, and other site work begins.
Center Line Locating
ListedCenter Line Locating is a woman-owned utility locating and underground infrastructure services company based in Charlotte, North Carolina. The company provides public and private utility locating, utility mapping, hydro excavation and soft-dig services, CCTV pipe inspections, jetting and flushing, continuity testing, underground system cleaning, and trenchless point repairs. Its services help contractors, engineers, developers, municipalities, and property owners identify and verify buried infrastructure before excavation, construction, design, or maintenance work begins. Center Line Locating serves projects throughout North Carolina and South Carolina, with additional project-based work across the Southeast, emphasizing accurate field data, utility verification, detailed documentation, and damage prevention.
Core Dynamics GPR
ListedCore Dynamics GPR Inc. is a California-based subsurface investigation and damage-prevention company specializing in ground-penetrating radar (GPR), private utility locating, concrete scanning, and GPS mapping. The company works with contractors, property owners, engineers, and construction teams that need to identify hidden utilities or structural elements before excavation, drilling, coring, saw cutting, or other potentially destructive work begins.
Northern Lights Locating & Inspection, Inc. provides underground utility locating, mapping, inspection, and damage-prevention services for contractors, utility companies, municipalities, property owners, and construction teams. Based in Indiana, the company supports projects where accurate identification of buried infrastructure is critical before excavation, paving, grading, drilling, or other site work begins.
StrataTrace LLC
ListedStrataTrace LLC is a New Jersey utility locating and subsurface documentation company that helps contractors, property owners, and project teams identify buried infrastructure before excavation or construction begins. The company specializes in private utility locating, electromagnetic detection, excavation safety support, and as-built utility mapping, with an emphasis on finding privately owned lines that may fall outside the scope of standard 811 mark-outs.
Related locating services
Subsurface utility engineering
Compare mapping deliverables with a formal quality-level process.
GPR utility locating
Review one source of subsurface field evidence.
Electromagnetic utility locating
Review conductive tracing as a mapping input.
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