For many organizations, such as local/county/state governments, providing public access to GIS data is a challenge.
Simply knowing what data is available, what it is, who owns and maintains it, and where to get it is probably the most immediate challenge. Therefore a GIS data inventory is a necessity. Of course, creating one is one thing, getting people to maintain it (and assume responsibility for their data) it is quite another. Therefore getting buy-in from internal stakeholders is also very important.
Another important consideration is a solution's support for metadata. If the data cannot be described, it is almost useless. With some solutions there may be limited support for metadata in the form of a limited number of proprietary fields. Support for metadata in its full and original form seems to be rare.
There may be limitations on the size, number of records/attributes, field lengths, or the geometric complexity of common GIS data, such as address points or parcel data that might make some solutions unusable. Often, the sheer size of some types of data (e.g. LiDAR, aerial imagery) makes it difficult or impossible to host them over the internet in their raw form, and instead they must be delivered via physical media (e.g. hard drives). At best, these large files may be hosted on something like an FTP server or Dropbox/Box, but it may be quite costly to do so.
Additionally, in many implementations, the spatial nature of the data may not considered to be important - or considered at all - making finding, viewing and using spatial data spatially difficult or impossible. Things like being able to symbolize the data in any useful way may be nonexistent.
Lastly, keeping the data up-to-date is vital. If there is no automated way to update data then the whole thing becomes unworkable for non-trivial amounts of data.
So with that out of the way, the main question is:
- What open data portal solutions are available and how do they compare?
What are the most important considerations when deciding on an open data portal solution?
Are there scenarios where using more than one portal is beneficial (and cost-effective)?
Can spatial and non-spatial data be successfully integrated into the same portal?
Are there any examples of open data portal implementations you would consider to be successful or exemplary?
A list of portal solutions that we are currently evaluating:
Other portals we haven't yet considered:
Not really portals but work well for serving flat files:
Rolling your own, either using hosted storage/servers or on-premises
Personally, I'd rather see us use more open source software, but it seems unlikely we'd be able to put something together that could compete with ESRI's offerings, at least not without a paradigm shift in the way people use GIS in our organization.
However, I hope that this question becomes a useful resource to anyone looking to improve access to public data.