Growing populations plus finite land resources mean communities need to plan future development more carefully, and this is where geographic-information systems (GIS) come in. With two- and three-dimensional modeling tools, such software helps the decision-making process take on a character far more sophisticated than the lines, squiggles, and other arcane symbols only city planners can readily understand. Entering readily available geospatial data is only the beginning; the key to using GIS effectively is informing and involving local citizens. Community residents combine local knowledge, concern, and commercially vested interests. A GIS needs to offer swift, simple, and transparent tools to aid decision-making. By no means does this imply simplifying the process; garbage in will inevitably lead to garbage out, and that's no more than a waste of time and money. GIS tools must also therefore provide for appropriate levels of complexities when various community systems interact. ESRI's ArcGIS is one such program, offering geospatial tools that can run as dialog boxes, functions in through commands and scripts, or inputs for models in Model-Builder. CommunityViz from the Orton Family Foundation is another high-quality product facilitating an open planning process. Its features include Scenario 360, the basic framework for comparing alternatives, and SiteBuilder 3D, capable of converting two-dimensional geospatial data into three-dimensional imagery.