The subpar performance in mapwork among matriculants in South Africa raises questions about the level of content knowledge (CK) competence of geography teachers. The study assesses the potential for improving the mapwork CK gap by utilizing empirical evidence from the mapwork in-service teacher training conducted at the University of Johannesburg, South Africa. Participants included 65 educators in 2017, 109 in 2019, and 52 in 2021 from Gauteng Department of Education (GDE) district schools. The study employed a mixed-method approach. Data was collected using survey questionnaires. The findings show significant improvements after training in identifying and interpreting features on maps and orthophotos. However, low improvements in factor ratings were observed in complex calculations, as well as in understanding cross-section, drainage patterns, stream order, intervisibility, geographical information system (GIS), and remote sensing. The study suggests that employing non-specialist teachers to address geography teacher shortages, alongside the low aptitude for twenty-first-century skills among older teachers, negatively impacts CK in GIS and remote sensing. The overall increase in factor ratings across all topics indicates that short learning programmes in map skills have the potential to enhance CK. The study recommends nationwide training in mapwork and providing schools with essential GIS and remote sensing technology.