First off, it is not possible to use dataex to describe my current dataset since there is a data permission issue.
However, I believe that anyone can understand the data format.

I have two separate data files to run "geonear" command. One has total 1643 observation with a unique id (variable named id1) with latitude and longitude (e.g., lat: 29.631 long: -81.7397) and the other data includes 1920 obs with a unique id (variable named id2), lat and longitude. The ids from each data are not overlapped. Here is the code below to identify each id2 within 10km distance from id1.

Code:
geonear id1 lat lon using "houses.dta", n(id2 lat lon) within(10) long
After I ran this code, for whatever reasons, there is only one id2 identified regardless of the specified distance (10km). To be more specific, each observation from id1 (total 1643 obs) is matched to only one of the observation in id2 out of 1920 observation and the all distances between them were around 9000 km, which was not reliable. I do not understand this result. I expected to see every possible pairwise between id1 and id2 within 10 km distance so that I can identify the number of locations per id1. Would a maximum capacity of dataset makes this matter? Thank you.