Residential exposure to magnetic fields generated by overhead high-voltage power lines, continues to be a mat-
ter of social concern and, for the scientific community, a challenge to model this exposure accurately enough to
reliably detect even small effects in large populations complexes. In any expression of the magnetic field inten-
sity, the source-receiver distance is a determining variable, especially in an environment closer to the electrical
installation and critical with the existence of significant unevenness in the terrain. However, MF exposure studies
adopt, due to their complexity, simplifications of reality where even sometimes the terrain relief and the buckling
of the line are not considered. The application of 3D techniques with Geographic Information Systems (GIS) al-
lows us to address this problem. This article presents a model for generating magnetic field intensity surfaces
from high-precision terrain elevation data. The series expansion of the Biot-Savart law to an infinite rectilinear
conductor with variable height according to the catenary described by the cables using ArcGIS software is applied
to calculate the magnetic field. For the validation, 69 control points (1035 field measurements) were used in a
free urban area and another 28 points (420 field measurements) in a built-up urban area with complex relief.
Good estimates were obtained, although with differences in both areas. With MAPE 9.65% and 19.51%, R2 =
0.922 and 0.949, RMSE = 0.154 and 0.094 μT, respectively. Furthermore, 86% of the points were correctly classi-
fied according to usual exposure percentiles. However, the use of a 5 m resolution digital terrain model to obtain
high-precision elevation data was an indispensable condition for the good performance of our model. The result
as a continuous surface of magnetic field values at the real elevation of the ground can contribute significantly to
the development of new environmental and public health studies.
