MOST COMMON GIS TERMS
Given its wide range of applications, Geographic Information System is full of terms derived from different industries. Some terms are more common in a given field than others.
The following is a list of the most common GIS terms in the oil and gas industry. They are so common that some managers bring them up during interviews to test candidates’ knowledge of the industry’s jargon.
Being familiar with these terms will help your day-to-day communications with your colleagues.
Shapefile is the old most common format for storing non-topological data used by a lot of GIS systems. A single shapefile is made up of at least three files (.shp for storing features(geometry), .dbf for storing attributes(records), .shx an index file connecting .shp and .dbf). Because of the limitations, shapefiles these days are primarily used for data transfer as email attachments or website downloads/uploads.
Feature class is also a format for storing data. Additionally, feature classes have topological relationships and the ability to store high-precision geometry. All features in a feature class must have the same geometry type, the same set of attributes and the same coordinate system.
Feature classes reside in a geodatabase.
A relational database optimized for storing, accessing and managing spatial data. It stores geographic features, their associated attributes and relationships that exist among them. A geodatabase can be for personal use or enterprise-wide applications.
A polyline spatial representation of the pipeline. This measure-enabled geometry represents a pipeline from its beginning to the end with no gaps.
This is the M value. It represents a location along a pipeline from a known point of origin. The pipeline measure value may or may not be the same length as the pipeline segment it represents.
Point of Inflection: This is a point where the centerline changes direction. Depending on the size of the pipe and the bend, the point of inflection is where field bends and/or elbows are located.
This refers to changing geometry and length of the pipeline brought about by changes along the original route. The changes could be anything, ranging from safety or environmental concerns, a new development in the area, or repair work.
When a pipeline is re-routed, an equation is necessary to account for the change in length. An equation station will have both Back (XX+XXBK) and Ahead (XX+XXAH) measures. The back value will represent the measure at that station after the change and the ahead value will represent the measure before the change.
In-Line-Inspection (also known as smart pigging) is a method of inspecting pipelines that operators are required to conduct periodically as part of integrity management. ILI measures and records pipeline irregularities including cracks, deformation, metal loss and other defects.
A feature on a drawing that’s used to communicate desired alterations to the original plan.
High Consequence Areas are segments of pipelines that pose a great risk to the public. These are areas with high population density and/or limited mobility facilities (schools, prisons, hospitals). They also contain drinking water and ecological resources where a pipeline accident is likely to cause long-term irreversible or irretrievable damage.
Commercially navigable waterways are also considered HCAs. They are significant to the country’s economy and security.
Pipeline operators in HCAs are required to devote additional focus and resources to ensure the integrity of pipelines
A regulatory designation for transmission pipelines based on their proximity to buildings (especially ones intended for human occupancy) within a certain distance. For onshore pipelines, a class location ‘unit’ is an area extending 660 feet on either side of any pipeline longer than 1 mile.
Class locations are determined by counting the number of buildings/dwellings within a ‘unit’ and are designated as Class 1 (rural) to Class 4 (densely populated). Areas where buildings with four or more storey are prevalent are also designated as Class 4. Class designation can change as the population of the area changes.
Class location of a pipeline determines its maximum allowable operating pressure.
This is not a complete list. Feel free to leave a comment if there’s a term that’s missing.