Only by taking a broad perspective can you see the whole picture.
Tips
history
Based on 荀子·劝学: 我尝跂高而望矣，不如登高之博见也 - Xunzi argued that standing on tiptoe is no match for actually climbing high. The idiom extracts the metaphor: height of position yields breadth of vision.
usage
Literal use (mountain climbing, observation decks) exists but figurative political/strategic use dominates in modern writing: 登高望远，谋划长远. Common in speeches by officials and executives.
