Thoughts on spatial data warehousing

I’ve been thinking quite a bit lately about how to store spatial data. It’s something I’ve covered here and my attitude towards this topic has evolved over the years.

The organisations I’ve worked in have mountains of spatial data accumulated over the years. The data is stored in shapefiles, geodatabases, normal databases, spreadsheets, documents, reports, photos…Why is it this way? It doesn’t have to be this way. It shouldn’t be this way!

In the course of my research for a topic for my project for next year, I’ve honed in on the methods for implementing an enterprise geoportal within an existing spatial data infrastructure. However, I feel like my focus is shifting to the data that the geoportal is trying to expose to a larger audience.

The concepts of a spatial data warehouse and a spatially enabled operational data store have been intriguing me. A regular GIS task involves comparing spatial data across a time period, analysing trends and presenting the results in a map or report. Why aren’t we storing this historical data in a SDW that’s optimised for reporting?

Non-spatial data can come from a variety of sources as well – spreadsheets, other databases etc. Another common GIS task is to spatially enable these datasets. Why are we not storing the outputs in a spatial enabled operational data store in an open format like GML?

I think it’s because to plan and implement a SDW/S-ODS takes time (and money). With a normal EDW, the organisation will not need much convincing to see the benefit of implementing one. “Spatial” is still seen as an “add-on”, or a “nice-to-have”.