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How did electronic distance measurement change surveying work?

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surveying Figure 1: Photogrammetric photographs from two short, overlapping flight strips arranged for supplying mapping details. Photo-control points are shown on only one photograph; shading indicates a typical terrain feature such as a lake (see text).

Electronic distance measurement (EDM) revolutionized surveying by enabling the accurate and efficient measurement of distances electronically, a task that was previously tedious and slow when performed with physical chains or tapes.12

By timing the passage of radiation—such as microwaves, light, or infrared—over a distance, EDM made the process of trilateration practical for large or hilly areas, whereas it had previously been limited to small, flat terrain. This technology also greatly simplified "traversing," a method of establishing survey frameworks by measuring a succession of distances and angles.2

Key impacts include:
* Increased Efficiency: It eliminated the need for the slow, manual measurement of all distances by tape or chain.2
* Versatility: Different types of radiation allow for flexibility; microwaves can penetrate atmospheric haze, fog, and foliage, while light or infrared radiation is effective for shorter distances.2
* Improved Accuracy: By electronically detecting phase shifts in a signal, EDM provides high-precision measurements that are essential for modern geodetic work.2

These advancements, alongside the later adoption of lasers, have significantly increased the speed and accuracy of field operations.12