GEOG 585
Open Web Mapping

Ways of opening data


Lately, it seems that "open data" is everywhere. Reaching buzzword status, this term is often seen in tandem with phrases such as "open government," "crowdsourcing," "government transparency," and "free and open source software."  But what makes data "open"? Just as you learned in Lesson 1, that different organizations, even proprietary software companies, employ the term "open source" to their advantage. There are various nuances to the term "open data" that you should consider whenever you hear someone touting this phrase.

Consider the following means of data access and how they might be placed on a continuum of more or less "open":

  • The data is not available in any format for the public to view or download (the baseline case of "closed" data).
  • The data is distributed in static format only, such as a paper map or PDF.
  • The data can be viewed by anyone through a web map, but not downloaded.
  • The data can be accessed by anyone through a web service and displayed in a GIS or web map, but the full dataset cannot be downloaded.
  • The data can be downloaded in proprietary data formats at no cost.
  • The data can be downloaded in open formats at no cost.

Consider how these levels of data access play into the following scenarios:

  • A person exposing a dataset claims that "the data is open because I let you see the data;" however, the data itself may not be available for download due to licensing, security, technical, or human resources restrictions.
  • An "open data portal" might expose datasets for free download, yet some items in the portal may only be available in formats readable by proprietary software.

The most open types of data are those that allow complete download, re-use, and modification of the data in open formats. However, other levels of data openness may be more useful than not seeing the data at all. If you expose a useful dataset through a web map or a web service, you should prepare an answer for the question, "Can I download this data?" It won't be long before somebody asks.

Open data licenses

Even when data is freely available for download in open formats at no cost, it may still be subject to licensing restrictions. There are numerous types of open data licenses that stipulate what types of applications can use the data (personal, noncommercial, commercial, etc.) and what kind of attribution must be given. The license may also state the types of modifications that are allowed on the data, especially if the modified dataset is to be redistributed.

To get a feel for some of these licenses such as Creative Commons, Open Database License, Open Government License, and Public Domain, please take a few minutes to read pages 4 - 8 of Licensing Open Data: A Practical Guide by Korn and Oppenheim, 2011. Focus especially on the chart on page 6.

Proprietary software and open data

FOSS typically excels at working with open data formats; however, FOSS is certainly not the only option for creating, exposing, or using open data. For example, Esri has invested in building open data discovery and download mechanisms into its ArcGIS Online and Portal for ArcGIS products. The idea is that government customers will be more likely to maintain their data in the proprietary software repository if the repository is easily engineered to allow free and open downloads by the public in popular formats such as KML and CSV. Here is the video of an interview with Esri's Andrew Turner from the Esri DevSummit 2017 on the topic of Open Data that you may find interesting.