When someone mentions a "wire frame model" in GIS, what are they referring to?

A wire frame model in GIS refers to a representation using a mesh of lines that define the shape of an object without solid surfaces. This type of model is commonly utilized in terrain modeling, where the simplicity of the wire frame allows for easy visualization and manipulation of surface data.

TINs, or Triangulated Irregular Networks, are a specific type of wire frame model that represents continuous surfaces. They consist of a network of triangles created from a set of irregularly spaced points. This method is particularly effective in capturing the nuances of terrain because it can accurately model varying elevations, providing a detailed representation of the landscape's shape and slope.

The other choices do not relate to wire frame models. Raster models are grid-based representations of data, primarily consisting of pixels, and do not provide a wire frame structure. Attribute tables store non-spatial data associated with geographic features, which is fundamentally different from the geometric representation of a wire frame. Network models focus on the connections between nodes and edges, which does not conform to the concept of a wire frame structure capturing physical shapes.