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Topographic maps, the systematic spatial ordering of neurons by response tuning, are common across species. In Drosophila , the lobula columnar (LC) neuron types project from the optic lobe to the central brain, where each forms a glomerulus in a distinct position. However, the advantages of this glomerular arrangement are unclear. Here, we examine the functional and spatial relationships of 10 glomeruli using single-neuron calcium imaging. We discover novel detectors for objects smaller than the lens resolution (LC18) and for complex line motion (LC25). We find that glomeruli are spatially clustered by selectivity for looming versus drifting object motion and ordered by size tuning to form a topographic visual feature map. Furthermore, connectome analysis shows that downstream neurons integrate from sparse subsets of possible glomeruli combinations, which are biased for glomeruli encoding similar features. LC neurons are thus an explicit example of distinct feature detectors topographically organized to facilitate downstream circuit integration. • Lobula columnar (LC) neurons are tuned to distinct features of object motion • LC18 detects motion of very small objects by comparing contrast changes in time • LCs project to optic glomeruli that are spatially ordered by visual feature tuning • Downstream neurons integrate from sparse subsets of neighboring glomeruli By combining calcium imaging and synaptic connectivity analysis, Klapoetke et al. reveal that optic glomeruli in the fly central brain form a topographic visual map, with glomeruli anatomically ordered by visual feature selectivity. Downstream circuits appear to exploit this map by integrating primarily from nearby glomeruli encoding similar features. [ABSTRACT FROM AUTHOR]