Maps are vital tools for most government agencies and consumers. However, their manual generation and updating is tedious and time consuming. As a step toward automatic map generation, we introduce a novel system to detect houses and street networks in IKONOS multispectral images. Our system consists of four main blocks: multispectral analysis to detect cultural activity, segmentation of possible human activity regions, decomposition of segmented images, and graph theoretical algorithms to extract the street network and to detect houses over the decompositions. We tested our system on a large and diverse data set. Our results indicate the usefulness of our system in detecting houses and street networks, hence generating automated maps.