In GIS, what does a Raster Model consist of at its core?

A Raster Model in Geographic Information Systems (GIS) fundamentally comprises a grid of pixels, each of which holds specific attribute values related to geographic data. This model represents spatial information in a format that divides the area into small squares, commonly referred to as pixels or cells. Each pixel corresponds to a particular location on the Earth's surface and contains a value that indicates a characteristic of that location, such as temperature, elevation, land cover type, or other phenomena.

The use of a raster model is particularly advantageous for continuous data, where variations across the landscape need to be represented seamlessly, such as in satellite imagery or digital elevation models. The uniform grid structure allows for efficient data processing and analysis, making it easy to perform spatial calculations, filtering, and rendering for various applications in GIS.

In contrast, the other options refer to concepts that do not encapsulate the core aspect of a raster model. While measurement units are fundamental in GIS, they don't define the raster structure itself. Survey points in 3D space pertain more to vector models, which utilize points, lines, and polygons to represent geographic features. Similarly, vector lines representing boundaries highlight another GIS model type focused on discrete features rather than the pixel-based approach that defines raster models.