Original mapping scale: In general, the original mapping scale can be thought of as a proxy for level of detail. For example, a map created at a statewide scale will not capture features like landslides, which are most commonly seen at a local, or zoomed in, scale.

Original mapping purpose: This factor can be thought of as the scope of the mapping. For example, a mapping project focused on bedrock and groundwater may mostly ignore surficial features like landslides.

Information and technology available at the time of mapping: Technology has been rapidly increasing our ability to map landslide hazards, specifically in the last 20 years. For example, a mapping project completed in the 1970s or 80s would not have used computers, GIS, orthophotography, or lidar-derived topography, and thus many landslides would have been missed. Burns (2007) concluded that in Oregon, lidar must be used for a complete and detailed landslide inventory.

Background of and interpretation by original mapper: Geologists with proficiency in engineering geology, geomorphology, and hazards backgrounds may make more specialized maps with detailed hazards information than others without that type of specialized training.