About Terrain Mapping
Terrain maps contain polygons, labels describing the attributes of a polygon using codes, and onsite symbols (symbolizing features such as landslide tracks or cliffs) overlain on a topographic base. A terrain map shows an area of land divided into terrain map units defined by similar elevation, slope, landform, rock exposure, surficial material type and thickness. Terrain Mapping different from Terrain Resource Information Management (TRIM) which is topographic baseline mapping.
Surficial geology mapping is similar to terrain mapping in that it includes information about surficial materials, and landforms. In BC, surficial geology mapping, soil and slope maps, and others were precursors to development of the Terrain Mapping Classification Standard (PDF). These legacy maps are available as scanned maps. The Geological Survey of Canada's terrain mapping follows a "Surficial Geology" classification system, coding and database structure which differs from B.C.'s Terrain Classification Standard.
Types of Terrain Mapping
There are three types of terrain mapping:
Terrain inventory mapping is a multi purpose inventory that describes the characteristics and spatial distribution of:
- Surficial materials, the surface materials on top of bedrock
- Landforms, the surface expression or 3D shape of surficial materials
- Geomorphological processes, the mechanisms that continue to deposit and modify surficial materials
- Geomorphological features in the landscape
Terrain mapping is intentionally generic in nature to serve a variety of land use planning and management needs. Other forms of terrain mapping can be derived from this type of terrain map with review, modification and field verification.
Terrain stability or slope stability is the susceptibility of a terrain polygon to slope failure. Terrain Stability Mapping describes landforms, surficial material, geomorphological features and processes, and also rates each terrain polygon to indicate relative stability using a qualitative scale.
Classes may have some quantitative descriptions relating to landslide frequency and magnitude. Additional features related to stability are indicated using on-site symbols. These include landslide headscarps, debris flow tracks, tension cracks, and gullies. Familiarity with the criteria used for the evaluation of slope stability and an understand the limitations of the mapping for each project is important. The criteria in adjacent mapping projects may be different.
There are two types of terrain stability maps:
Reconnaissance Terrain Stability Mapping
Usually only the unstable and potentially unstable areas are given terrain labels. Stable areas are not subdivide or given a terrain label. Classification system: Uses a three-class system:
- U - unstable
- P - potentially unstable
- S - stable
Terrain survey intensity level (TSIL): Typically D or E. Uses: For landscape level planning, to identify areas requiring more detailed study, flagging areas that warrant on site investigation by a terrain stability expert.
Detailed Terrain Stability Mapping
The entire landscape within the study area is divided into terrain polygons with terrain labels. Classification system: Uses a five-class system
- I - very stable
- II - stable
- III - moderately stable
- IV - potentially unstable
- V - unstable
- Sometimes IVR and VR are used to indicated that road construction may cause instability
Terrain survey intensity level (TSIL): Typically A, B or C. Uses: Planning, terrain hazard and constraint identification, other related interpretations. Detailed terrain description can be used to derive other information (e.g. aggregate resources).
Bioterrain mapping is typically an input into an interdisciplinary terrestrial or predicted ecosystem mapping product that shares common polygon linework, or it may be a stand-alone product. Bioterrain map units are delineated with an ecological lens on surficial materials, landforms and geomorphic processes.
Find out which type of mapping best suited for your information needs or learn how to interpret terrain mapping data:
- Three Types of Terrain Mapping - Diagrams (PDF)
- Comparison of Terrain, Terrain Stability and Bioterrain Mapping (PDF)
- Usefulness of Terrain Stability Mapping for Bioterrain Purposes - A Discussion Paper (PDF)
Terrain Mapping Process Steps
- Project planning and review of existing information and previous work
- Preliminary air photo, satellite, Lidar or other image interpretation (in 3 dimensions) and creation of draft polygon linework (with polygon attributes) and on-site symbols (landslide tracks)
- Field work to confirm/ground truth preliminary mapping
- Revision and finalization of the mapping on the images
- Digitization, database creation and map production
- Write a project report that describes the geographic setting, methodology used, assumptions and criteria used and other information about the project and how the terrain map should be interpreted and used
- Map originals are signed by the project's professional terrain mapper and project deliverables are submitted to the provincial government
- Quality assurance review/audit
Terrain mapping is done by qualified professional terrain mappers who are in good standing with their professional governing body in B.C. and who have the skills and education required to complete terrain mapping. Qualified professionals are typically geologists, geoscientists, soil scientist, geological engineers or geographers with relevant mapping experience and expertise. GIS technicians are also involved in terrain mapping projects and play a critical role in capturing the mapping data into digital formats consistent with digital standards and requirements.
- Terrain Mapper Skill Set (PDF)
- Guidelines for Professional Services in the Forest Sector-Terrain Stability Assessments (APEGBC/now EGBC, 2010)
Besides the mapping team, there are other players involved either directly or indirectly in a terrain mapping project, including:
- The organizational client for whom the mapping is completed (commonly a forest sector company or other client operating on the land base)
- The provincial government terrain data custodian
- Funding bodies such as FIA
- Professional associations
- Terrain data users
- Follow standards of practice.
- Conduct terrain mapping following appropriate standards and guidelines
- Ensure correct mapping procedures and Best Management Practices have been followed
- If acting as a project manager, at project initiation, request a BAPID, otherwise, ensure that this has been done.
- Provide all deliverables in accordance with contract specifications and RISC and other applicable standards.
- Develop and follow internal QC procedure; use external QA/QC as appropriate.
- Provide edit/quality control (QC) of final deliverables (verify hardcopy maps, database, report and spatial files).
- Sign and seal the final deliverables.
- Adhere to professional’s association Code of Ethics and Act.
- Maintain up-to-date registration and good standing with an appropriate professional organization (e.g., APEGBC/now EGBC, BCIA).
- Continue professional development in the area of terrain mapping.
- Ensure contract standards and specifications are up-to-date and that all relevant RISC or other applicable standards have been clearly specified in the contract.
- If acting as project manager, at project initiation request a BAPID or verify that this has been done by the Terrain mapper or other project manager.
- Ensure all deliverables meet contract and specified standards.
- Ensure all deliverables are delivered upon project completion date to the Terrain Data Custodian (applicable to all government funded projects, (including FIA) and projects required for environmental assessment or to meet other regulatory or legislated requirements).
- Ensure that the terrain mapping team has the appropriate qualifications and skills.
- Ensure deliverables have been signed and sealed by the appropriate professional
- Provide for third party Quality Assurance (QA) if the client does not have the resources in-house to ensure that the deliverables are to standard.
- Document any proposed variances from RISC standards and obtain the Terrain Data Custodian’s approval.
- For a FIA funded project, ensure all FIA-related requirements are met.
- Ensure all RISC or other applicable digital data capture standards are met.
- Ensure terrain feature codes and source feature codes are preserved in the final deliverables.
- Ensure dotted/dashed/solid lines are captured (through use of appropriate fcodes)
- Provide metadata and other documentation as appropriate.
- Manage digital terrain data.
- If upgrading an existing dataset, follow procedures set out the digital data capture standards and the TEI Data Submission Standards, or contact the Terrain Data Custodian for more information.
- Utilize the TEI data validation tools available.
- Consult a terrain professional as required.
- Maintain standards of practice.
- Maintain a current list of members-in-good-standing.
- Discipline members found in breach of the Code of Ethics or who do not adhere to the professional association’s Act.
- Discipline individuals practicing geoscience without a licence.
- Ensure that qualified registered professionals are hired to complete the terrain information portion of the FSP.
- Ensure that terrain deliverables are signed and sealed by a qualified registered professional.
- Ensure that the qualified registered professional used is registered and in good standing with an appropriate professional association.
- Ensure that terrain information is incorporated into the FSP and has been submitted to the data custodian.
- Ensure that the project terrain specialist is a qualified registered professional in good standing.
- Ensure that a sign off letter from the terrain professional is included with the project.
- If the bioterrain dataset is a separate project from the ecosystem dataset (for example a bioterrain map that is an input to a PEM), follow the terrain standards and ensure the dataset has been submitted to the data custodian.
- Maintain the Terrestrial Ecosystem Information (ecosystem, soil, terrain and wildlife habitat) classification, inventory and digital data capture and submission standards.
- Collect, compile and maintain data in a central repository or repositories, and provide access to this information, as appropriate (recognizing some data may be proprietary).
- Provide expert advice to clients, partners and stakeholders.
- Clarify and approve variances from RISC standards.
- Provide client-focused products and services.