Contour lines and DTM: why every ranch should have one
A ranch without a digital terrain model (DTM) is run by eye. With a DTM, every decision — where the water reservoir goes, where the road runs, which paddock floods — is made on data with centimeter precision. In a subdivision, the same DTM solves street runoff and drainage before municipal approval.
What is a DTM?
It is a mathematical representation of the land surface: millions of points with X, Y coordinates and Z height. Contour lines, slope maps and water runoff analyses are derived from it.
How do we generate it?
- Photogrammetric drones: they cover hundreds of hectares per day at a resolution of 3–5 cm per pixel.
- RTK geodetic GPS: control points with centimeter precision, georeferenced to the official RUN framework.
- Processing: photogrammetric software that produces a point cloud, orthophoto and contour lines at intervals of 25 cm, 50 cm or 1 m depending on use.
Decisions it enables
- Water reservoirs and ponds: locating the exact point of maximum catchment with minimum earthmoving.
- Internal roads: routing along ridges to avoid mud and access cutoffs in the rainy season.
- Drainage and agricultural contour lines: the basis for contour planting and erosion control.
- Valuation: a ranch with a DTM, orthophoto and an up-to-date survey is worth more and sells faster.
In the Chaco we have surveyed ranches of more than 1,800 hectares in campaigns of a few days. The cost of the study is usually recovered with the first well-placed water work. If the plan is to subdivide the land, the DTM is also the first input for the legal requirements of subdivision.