Cities around the globe are challenged by the ever-growing quantity of urban citizens in order to ensure sustainable urban development. Mapping cities and other urban spaces seems like a complex task for data capture, representation and visualization. However, understanding, describing, and modeling the geometry and behavior of cities are significant challenges that ultimately benefit urban planning, mapping and visualization, emergency response, etc. Using interactive 3D datasets to assist in the design and visualization of complex 3D city models is vital.

3D city models are digital models of urban areas that represent terrain surfaces, sites, buildings, vegetation, infrastructure and landscape elements as well as related objects (e.g., city furniture) belonging to urban areas. Their components are described and represented by corresponding two-dimensional and three-dimensional spatial data and geo-referenced data.

We at "Prashant Surveys" use the combined technology of 3D Mobile LiDAR & UAV (unmanned aerial vehicle) / drone for preparing the 3d base map up to the accuracy of +/- 5 cms. By this technology we can capture and generate 3D point cloud data sets and photographs, which are the basic requirements of 3D modeling.

The drawings and data sets thus generated are to the scale of 1:500 or 1:1,000 which is sufficient for development of smart city of any size.

In some cases, the combined technology of 3D Mobile LiDAR & High Resolution Satellite images can be used for generating the 3D base map up to the accuracy of +/- 20 cms. This method is more cost effective for small to medium sized municipal councils and cities which require about 1: 2,500 or 1:5,000 scale mapping.