I updated the urban extent shapefile, replacing the GRUMP dataset to instead use the Schneider, et al. (2009) MODIS-derived urban extents.

Schneider, A., Friedl, M., Potere, D., 2009, A new map of global urban extent from MODIS data. Environmental Research Letters, vol. 4, article 044003.
Schneider, A., Friedl, M., Potere, D., 2010, Monitoring urban areas globally using MODIS 500m data: New methods and datasets based on 'urban ecoregions'. Remote Sensing of Environment, vol. 114, p. 1733-1746.