Chapter 6

Remote Sensing in Precision Agriculture

Point Clouds

A point cloud is a collection of individual data points in a three-dimensional plane, with each point having a set coordinate on the X, Y, and Z axis. When each point is placed together, it creates a three-dimensional map or model. For example, if the data compiled to create the point cloud is taken from an orchard, it will show the location of each tree, along with its elevation relative to the ground. Point clouds are generally created using sensors like LiDAR, stereo cameras, structured light, and structured from motion. The output is a point cloud, which is a collection of data points in a 3D coordinate system, representing the shape and structure of an object or environment.

Digital Elevation Models

A digital elevation model (DEM) is a raster-based model that represents elevation values over a continuous surface. It’s often derived from point clouds by interpolating the Z-values of ground points. Converting Z-values of ground points from a point cloud to a DEM is a key step in turning complex 3D data into something usable for mapping, analysis, and decision-making.

Why Convert Z-values from Point Cloud to DEM

Simplify Complex Data. Point clouds contain millions of points and are hard to analyze directly. A DEM summarizes this data into a 2D raster grid where each cell holds a Z-value (elevation). This makes analysis and visualization much faster and more accessible.

Enable Terrain Analysis. By using only ground points, the DEM shows the bare-earth surface. This is crucial for: (1) slope & aspect analysis, (2) watershed modeling, (3) irrigation planning, and (4) field leveling in agriculture.

Application of DEMs in Agriculture

Digital elevation models are super valuable in agriculture, especially in the age of precision farming. They help farmers, agronomists, and land managers better understand the shape of the land, which directly affects water flow, erosion, crop performance, and field management. Some examples include:

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