I found the following entries on Wiktionary (emphasis mine):
- chart; map
From Middle English carde (“playing card”), from Old French carte, from Latin charta, from Ancient Greek χάρτης (khártēs, “paper, papyrus”).
From Middle French charte (“card, map”), from Late Latin charta (“paper, card, map”), Latin ("papyrus, writing"), from Ancient Greek χάρτης (khártēs, “papyrus, thin sheet”).
- sheet of paper
From χαράσσω (kharássō, “I scratch, inscribe”), from Proto-Indo-European *ǵʰer- (“to scratch”).
Probably from a blend of the Middle English words scratten (“to scratch”) and crachen (“to scratch”).
I couldn't find any further etymology for scratch. It seems to me that Ancient Greek χάρτης (khártēs) is similar to Modern English scratch (e.g. a mid-point could be krats). Could these words have the same source as each other considering that the root word is hypothesised to mean scratch?