Volume 12, Number 2, July 2020 Join SIGSPATIAL NOW  Foreword i-iii Introduction to this Special Issue: Modeling and Understanding the Spread of COVID-19(Part II)Andreas Züfle, Taylor Anderson  1-2 Section 1: Modeling and Understanding the Spread of COVID-19  REACT: Real-Time Contact Tracing and Risk Monitoring using Privacy-Enhanced Mobile TrackingLi Xiong, Cyrus Shahabi, Yanan Da, […]