I'm working on a project to get the maximum elevation along a 10-mile wide corridor. To accomplish this I've loaded raster elevation data into a PostgreSQL database, and used the PostGIS extensions to give me the desired result.
I have two different resolution data sources (both from the USGS) available: a 100-meter resolution dataset, which can return a result from a roughly 627 nautical mile long line in about 3 seconds, and a 2-arcsecond resolution dataset, which takes closer to 10 minutes.
My question is, given that I am just looking for the maximum elevation over a large area, what, if anything, am I loosing by using the lower-resolution data? For example, could the 100 meter data "jump over" a ridge, giving lower elevations on either side and missing the higher elevation of the ridge top? Or would the lower resolution data "interpolate" the area between points somehow, such as the values being the maximum elevation in a 100-meter by 100-meter block, such that the ridge would be taken into account?
Keep in mind that I only care about the maximum elevation here - I don't care where exactly it is, so in that regard resolution is of little consequence (within reason). I just need to know that the maximum elevation I get from the dataset truly is the maximum elevation in that area.
EDIT: Both data sets come from the USGS. The 100-meter dataset is this one: https://nationalmap.gov/small_scale/mld/elev100.html, while the 2-arcsecond dataset is pulled from the DEM's available at http://viewer.nationalmap.gov/basic