APDM ArcGIS

1 The ArcGIS Pipeline Data Model is designed for storing information pertaining to features found in gathering and transmission pipelines, mainly gas and liquid systems. The APDM was expressly designed for implementation as an ESRI geodatabase for use with ESRI's ArcGIS and ArcSDE products. A geodatabase is an object-relational construct for storing and managing geographic data as features within an industry-standard (RDBMS).

The APDM was initially derived from existing published data models (primarily the earlier PODS (Pipeline Open Data Standard) and even earlier ISAT (Integrated Spatial Analysis Techniques) models) and was expanded to meet the needs of gas and liquid transmission pipelines. The APDM was developed by members of the ESRI Pipeline Interest Group. The model was designed to include a sampling of standard features typically found in 80 percent of pipeline companies, but was tailored to include current hot topic items such as integrity, pipe inspection, high-consequence areas, and risk analysis. In keeping with the spirit of other published ESRI models, the APDM is not designed to be a comprehensive or all-encompassing model. Rather, the APDM was designed to be a template from which a pipeline operator would start with the core elements of the model, and modify the model by adding features or refining existing features. A primary objective of the model was to account for linear referencing of features (stationing). Most companies refer to the location of features or events that occur along the pipeline system as events occurring along a route (station series) at a certain distance (measure). Stationing was handled in the model using out-of-the-box technology referred to as routes and measures.

The APDM was designed as a starting point. It was not the purpose and focus of the APDM technical committee to design a model that was a comprehensive description of all possible features found in a pipeline system. Nor is it the intention of the model to prescribe a rigorous methodology or standard approach to modeling pipeline systems. It was the intent of the model to provide a set of core objects and attributes that describe and effectively handle stationing, plus a core set of conceptual objects by which most, if not all, pipeline features could be categorized. The purpose behind providing a core set of features is to provide pipeline vendor companies with a consistent framework for developing applications against the model and for data transfer between existing databases. With this approach, any pipeline company can add features to the model, modify existing features in the model, or subtract features from the model as required by business needs. The core elements of the model remain a small subset of the features found in the model, and any new features added must fall into one of the conceptual APDM categories: referenced features or non-referenced features, online features or offline features. Another focus of the APDM was to develop a model that end users could implement, and add data to without the need for custom code or development efforts.

The APDM has existed as a published model since 2001 and is now available in version 4.0 for download at APDM.net.

Three significant difference between the APDM and the earlier PODS model are:

the APDM:

- is specifically designed to take advantage of ESRI Geodatabase Technology, 
- is intended to be flexible (the model can be implemented piecemeal, whole, modified and/or expanded) and
- is in the public domain (any pipeline operator can implement it without cost), 

while PODS:

- is not platform specific (users must design a process to 'GIS' the PODS tables), 
- must be implemented as a whole (but can added to if desired) and 
- is copyright protected and not a public domain model (users must be fee paying members the PODS association).  

Users of the PODS model cite the benefits of a richer model with more tables, while APDM organizations prefer the ability to model their pipeline system's specifics in the flexible template-like model. The PODS model is distributed as implementation scripts while the APDM is distributed in a UML format which allows organizations to easily begin expanding on the APDM template to create custom GIS objects inheriting from the APDM's abstract classes.