land surveyor here, have been surveying for 15 years and own a surveying firm going into its 3rd year ...and I think that there are multiple uses that you could proposition surveyors with. Of course basic aerial photos like you're talking about could be useful, but rarely. For that type of work I think you'd have better luck with architects or civil engineering firms. When it comes to surveyors the biggest draw is by far topographic 3d mapping. If you could find a surveyor that would hire you to do mapping missions alongside them then you could really tap into a niche market. It wouldn't be easy as even being one of their peers I had and have a hard time convincing some of them of a drones validity for mapping. But if you could break into it and get one to let you show them how it works(and you do it correctly) they would be blown away. Beyond 3d mapping even just 2d mapping and delivering orthomosaics could prove beneficial to them. I fly every as-built or topo site that I survey now because its faster and more useful than taking field notes and my clients LOVE having an updated aerial view of their future sites and completed projects. Engineering firms are a big market as well as most of them would love better aerial imagery than google earth, most just don't know its possible for relatively cheap.