USKI at SAIS has just published and worthwhile report by Benjamin Katzeff Silberstein, titled Growth and Geography of Markets in North Korea New Evidence from Satellite Imagery. Silberstein's analysis is helpful in a few ways.
It is clear - even though he admits that from above one cannot tell what's happening under the roofs - that markets have generally grown and despite ambivalent policies from above, permanent closures and removals of markets does not seem to have taken place.
He also draws attention to the fact that the western regions of the country have bigger markets relative to size. This also seems to be the case in cities with major ports, with only one of the top four market-size-per-capita not being a port city (Sariwon). He concludes that this reflects the importance of trade via sea routes, something often overlooked by Korea-watchers, who tend to assume that land-trade via Dandong is the most important. This probably reflects the visual nature of it: we humans lean heavily towards things we can see. Regardless, this is something we should keep in mind as we think about North Korea's foreign trade relations.
The variance of market growth in different cities does not appear to be linked to anything measurable at the moment, leading to a guess that "attitudes among local government officials may be one cause."
Local attitudes may also affect something that the paper does not cover, the spillover of buying and selling into areas around the markets, into other buildings and even onto the surrounding streets. This is a task that is impossible to measure from above, but travelers can see the difference between spillover in cities around the country. Again, impossible to measure in a meaningful way, unfortunately.
Below: a shot of a new building in Pyongyang next to North Korea's most famous market: Tongil Market. It is unclear if its function will be related to Tongil Market.