candidate site; proposed location
Refers to a site that is being considered or has been selected for a specific purpose, such as a new facility, event, or development project.
The candidate sites for the new airport have been narrowed down to three.
The city put itself forward as a candidate site for the next Olympics.
建設予定地 is a 'planned construction site', implying a more definite decision, whereas 候補地 is still under consideration.
Compound of 候補 (kōho, 'candidate') and 地 (chi, 'land' or 'place').