Presumption as to books, maps and charts

Reference: The Indian Evidence Act
Section 87

The Court may presume that any book to which it may refer for information on matters of public or general interest, and that any published map or chart, the statements of which are relevant facts and which is produced for its inspection, was written and published by the person and at the time and place, by whom or at which it purports to have been written or published.

Proof of a map is only proof of its preparation. A map can be considered to be a pictorial statement and as such, its maker must be called to the Court to prove its contents.
If the contents of the map were presumed merely by proving the map itself, it would amount to admitting hearsay evidence.