Spatial heterogeneity, or the variation of environmental conditions within a greenhouse, reduces productivity. High-definition heat maps can help mitigate this, but generating them in greenhouses is challenging. This paper compares multi-spectral cameras and wireless sensor networks (WSNs) for this task, evaluating them across eight criteria. Multispectral cameras excel in point density and sampling rate, while WSNs offer advantages in flexibility, cost, and installation time. Our findings suggest that hybrid solutions combining both technologies with robotics may enhance scalability and efficiency in greenhouse monitoring.