In nineteenth-century Joseon Korea, large-scale panoramic paintings vividly depicting royal palaces newly appeared. Yet, in the absence of surviving records, their precise purpose and function remain uncertain. This study examines the historical process that led to their emergence, situating them within the broader trajectory of Joseon architectural representation. Previous scholarship has treated palace paintings through separate art-historical and architectural approaches. This study instead emphasizes the transformation of practical architectural diagrams, produced since the early Joseon period for functional purposes, and traces their evolution into pictorial and panoramic paintings in the nineteenth century. Originally serving as design plans and simplified records of structures, architectural diagrams in the late Joseon period began to incorporate techniques from cartography and painting. This shift gave rise to forms such as Ganga-do (detailed architectural drawings with extensive information) and perspectival diagrams pursuing realism and spatial depth, which ultimately culminated in panoramic palace views. Palace paintings of late Joseon court were thus hybrid works, neither purely pictorial nor strictly technical. Produced by court painters under royal commission, they embodied both functional and aesthetic purposes, representing a distinctive synthesis of architectural knowledge and visual artistry in late Joseon Korea.