Despite the good performance of GPS, there are more than a few GNSS vulnerabilities and threats. Categorisation into unintentional and intentional is sometimes done to aid understanding. Unintentional disruptions include natural phenomena such as high levels of ionospheric disturbance and solar flares, as well as man-made phenomena including system errors (satellite or signal), and unwanted radio frequency transmissions (TV, microwave communications, radar, …).

Replacing the horizontal datum of a country is a complicated and difficult project. The decision to embark on such a “revolutionary” move should only be taken after in-depth studies to identify compelling reasons for such replacement. Here, we comment on the article by Tahir et al. published in the September 2011 issue of Coordinates.

As satellite imagery becomes increasingly ubiquitous, the mechanisms to deliver and disseminate this data have become critically important to both the consumers and providers. Aligning these dissemination tools with cloud hosting and computing is a natural

By definition, ‘spatial enablement in action’ means that we (governments) must make our spatial information “actionable”. That is, it must be used and leveraged beyond just for mapping. It must form the enduring fundamental authoritative spatial data layers of a nation, and do so in a way so that it is able to support evidence-based decision making for the many social, economic and environmental drivers challenges that face our Governments. It is incumbent on us doing so. Should we not do so, we seriously risk “spatial stagnation”, and have a rich resource of geoinformation that remains largely untapped and with significant unrealised potential.

GPR is a geophysical investigation method. Its principle is similar to that of Seismics but instead of emitting elastic waves, it emits electromagnetic waves. They are much shorter, which leads to a much higher spatial resolution. GPR is sensitive to the electromagnetic properties of the material under investigation. Interfaces of rock formations, fi ssures and aquiferous areas are displayed.