1to know sth like the back of one's hand (idiom)
2to know (a person, a place etc) inside out
Examples
wǒ我duì对niǔ纽yuē约liǎo rú zhǐ zhǎng了如指掌。
我对纽约了如指掌。
I know every inch of New York.
他对这个地方了如指掌。
He knows every inch of this area.
他对纽约了如指掌。
He knows New York inside out.