Linear Disturbance Features
Image credit: Hatfield Consultants
Linear disturbance products are typically delivered for linear features with a width between 1 and 30 m. The most common linear disturbance in oil and gas development areas is from seismic lines and roads, but can also include pipeline and transmission line corridors associated with a project.
Maps of existing linear infrastructure routes and corridors that may be abandoned or may belong to other operators are important for exploration and development planning and assessment of cumulative environmental effects. Existing linear corridors could be repurposed or shared rather than clearing new routes, both to reduce costs and minimise impacts.
EO data can help to identify existing linear features. Very high resolution EO products can deliver information about the extent and magnitude of disturbance along narrow linear corridors. If the contrast (in spectral response) between these features and the surrounding area is significant, then the centrelines of features smaller than the sensor spatial resolution can still be estimated. Multi-temporal EO data can be used to identify older disturbances and the extent of re-growth.
Linear feature extraction can be optimised using object-based classification methods, and pre‑existing vector data can be incorporated into the process. Conflation control is required to make corrections where data from multiple sources conflict. Extracted features require topology control and manual verification with editing.
The linear disturbances product delivers centrelines and standardized widths of linear features, and includes coding for feature themes, such as single or double track, surface type, seismic line, etc.
Known restrictions / limitations
Lifecycle stage and demand
Pre-license: Knowledge of pre-existing access corridors will facilitate geological and geophysical assessment.
Exploration: Knowledge of pre-existing access corridors will facilitate seismic and site surveys, and appraisals.
Development: Re-development or expansion of existing access corridors will reduce development costs. Wildlife populations are sensitive to linear disturbance density, which may need to be addressed in the environmental impact assessment (and for cumulative effects).
Production: Site security can be enhanced by accounting for pre-existing potential access points.
Decommissioning: Useful for monitoring of re-vegetation along decommissioned access corridors.
Geographic coverage and demand
Demand is global, especially in developing or remote areas where infrastructure maps may not be comprehensive. The mapping and management of cumulative linear disturbance is an important issue in North America.
OTM:062 Monitoring revegetation
Input data sources
Optical: VHR1, VHR2, HR1, HR2
Radar: VHR2, HR1, HR2
Supporting data: Aerial imagery, LiDAR
Spatial resolution and coverage
Spatial resolution: 0.5-15 m.
Varies depending on input imagery used and client needs. Very high resolution imagery is needed for very narrow feature detection (e.g., seismic lines).
Minimum Mapping Unit (MMU)
Variable, depending on source data resolution. The MMU could be very small (i.e., when derived from very high resolution optical data). Four metres is a typical single-track road width, although minimum feature width (MFW) could be less than two metres (e.g., narrow single-track roads or seismic lines).
Accuracy / constraints
Thematic accuracy: Accurate area estimates for features requires VHR optical data, e.g., within ± 10% of the actual area. Thematic accuracy is dependent on the number of classes being discriminated (road versus single track, multi-track, sealed, gravel, etc.), but recent linear disturbance can be extracted with >90% accuracy if using VHR optical data.
Spatial accuracy: Centrelines of features can be determined within 1-2 pixels.
Accuracy assessment approach & quality control measures
Topology of output vectors to be checked and cleaning to be performed. Automatic centreline correction for features of known width, and visual assessment with manual corrections for all linear features. Limited ground survey and comparison to ancillary vector data. Vegetation type and/or structural information would require field vegetation assessment survey.
Frequency / timeliness
Observation frequency: One baseline feature collection is needed. An additional yearly snapshot during the reclamation process supports monitoring activities.
Timeliness of delivery: Imagery and elevation can be acquired quickly. Data processing can be completed in near real time (< 24 hours) for detection of most easily visible linear disturbances (e.g., roads). The processing of data for more challenging areas (e.g., very narrow historic seismic lines) requires professional/expert interpretation and is typically a consulting assignment of weeks to months.
On-demand availability from commercial suppliers.
New acquisitions can be requested globally.
Delivery / output format
Linear Disturbance Features
# of Pages:
Internal – Project consortium and science partners
External – ESA
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