This e-planning visualization case study in the Toronto region investigated the use of 3D urban models as a visualization reference against which analytical models were visualized to identify micro scale mitigation scenarios of urban heat island effects. The case studies were directed to processes of planning decision making. The Toronto region faces problems of urban heat island impacts due to the increasing frequency of extreme heat events (Bass, Krayenhoff & Martilli, 2002). The City of Toronto and the Toronto and Region Conservation Authority (TRCA) have each implemented policies and programmes aimed at mitigating urban heat island and climate change effects (City of Toronto 2006). This research explored ways of visualizing remote sensing heat island data to assist with the targeted application of planning policies and programs.