Do you know the difference between data and content in a Web GIS Portal? Why would you use one over the other? Read this blog to find out the difference between the two, plus where to look for Canadian Web GIS content.
I recently attended a technology event where one of the speakers presented a slide demonstrating their web portal’s architecture. On the slide were lots of coloured boxes with arrows pointing in all directions. At the bottom of the slide were two boxes: one was labelled ‘content’ and the other was labelled ‘data’. I asked the speaker about these boxes and the distinction between data and content.
Architecture of the ArcGIS Portal showing content and data. Web content is provided by Web Services.
The presenter explained that the term ‘data’ was used in their web portal as something that was not immediately useable, but required additional processes to make it viewable. For example, analytical or statistical calculations could be made on the data and the results presented to the user. ‘Content’, on the other hand, has already been processed and was ‘baked’ into the portal so that it could be loaded and used immediately. In other words, content is ready to use while data needs further processing.
To me, the presenter’s answer to my question about data and content was reasonable in a business web portal context, but does this response also hold true in a Web GIS context? Let’s have a look at ArcGIS portal data and content.
Web GIS data has a useful purpose, but often not in its current form, as in most cases, additional processing is required to make it useable on the web. An example might be Digital Elevation Model (DEM) data. DEM data is normally stored in raster format, and if you simply look at it as a raster file in a desktop GIS or in a Web GIS, it just looks like a series of ‘out-of-focus’ light and dark areas. Not really that useful. However, if you contour the DEM or create a dynamic perspective view in 3D, then you see the incredible value of the DEM data.
Left: Example of DEM of South Eastern Québec and the Gaspé peninsula. Right: A perspective view of exaggerated elevation for the same region.
Another example of GIS data is a list of clients with addresses. This tabular data can be viewed on the screen as a table of values, but it is very difficult for humans to assimilate the data quickly, especially if the data table is large. However, the same data can easily and rapidly be geocoded based on the addresses, and then plotted on a web map. The web map is a much better way of presenting the data for human interpretation. For example, spatial relationships in the data are easily determined once the data is presented spatially on a map.
What then is Web GIS content? It is spatial data that has been pre-processed so that it can be quickly accessed and viewed on the web. Spatial content is organized, diverse, fast and ready to use. Some examples of web map content are weather, traffic, tourist attractions, snow removal, bird sightings, topographic maps and business locations. A common feature of Web GIS content is that it is most often provided to your browser as a web service. Common web service interfaces include Web Map Service (WMS), Web Feature Service (WFS) and Esri Rest Service.
Esri’s Living Atlas provides a number of ready-to-use map layers for Canada. These include Provincial and Territorial Boundaries, 1m IKONOS Imagery, Landsat Time-Enabled Imagery, National Railway Network and 2016 Canada Median Household Income. There is plenty of Canadian content currently available so check it out at the ArcGIS Living Atlas.
Canadian Web GIS content easily available on the Living Atlas.
If you need data on the society, demographics, transportation, boundaries or imagery of Canada, check out the content on the ArcGIS Living Atlas. You will be pleasantly surprised by the depth and breadth of the content that’s available. You can also create and publish your own web map content if you wish, using ArcGIS. This content can quickly be loaded into your Web GIS for viewing and interpretation.
So, do business portals and Web GIS portals use the same definition and differentiators for data and content? I believe so. In both these cases, data needs further processing while content is pre-made, accessible and ready to use.