Both drones and satellites produce imagery you can analyze in a GIS — but they answer different questions well, and the wrong choice usually means paying for resolution or coverage you didn't need, or missing what you actually needed.
Resolution and revisit frequency
Drone surveys capture very high resolution imagery — down to a few centimetres per pixel — because the sensor flies close to the ground. That's what you need to see individual structures, crop rows, or fine boundary detail. The trade-off is coverage: a drone survey covers a site or a few hundred hectares in a flight session, not a district.
Satellite imagery trades resolution for coverage and repeat frequency. Depending on the satellite, resolution ranges from under a metre to tens of metres per pixel, but a single pass can cover an entire district or state, and many satellites revisit the same area every few days — useful for tracking change over a season, not just a single point in time.
Rough cost bands
Drone surveys are priced per site or per hectare for a one-time flight, with cost driven mainly by site size, terrain, and how much ground-truthing or processing (orthomosaics, DEMs) is needed. Satellite imagery is typically priced per scene or via a subscription for repeat access, and free/open sources (like Sentinel or Landsat) exist at coarser resolution for use cases that don't need fine detail.
Matching the tool to the question
Site-level infrastructure planning — a road alignment, a building footprint, an earthwork volume calculation — needs drone-level detail; satellite resolution won't show what you need. Regional crop monitoring, land-use change over a season, or tracking deforestation across a large area is the opposite case: satellite's repeat coverage matters more than centimetre-level detail, and flying drones over that much area repeatedly isn't practical.
Many real engagements use both: satellite imagery to identify where to look (a change-detection flag, a region of concern), then a targeted drone survey to get the ground-truth detail needed to act on it.