人文地理地圖中和語言分佈地圖最為相關、可以作為比較材料的是祖籍分佈地圖。如果地圖繪製都一樣的精細、準確，不同時代的祖籍分佈地圖和語言分佈地圖可以作為族群遷徙、語言轉移的歷史證據，如果其中一方有所錯誤或不足，採用為歷史材料時，其歷史價值就必須審慎評估。本文從小川尚義的「臺灣言語分布圖」(1907) 說起，討論如何鑑別族群語言地圖文獻的歷史價值及重建史實的可能。

Among various kinds of humanistic geographic maps, ancestral racial or homeland map is the most relevant and comparable with linguistic distribution map. If both of them were drawn with the same extent of accuracy and correctness, ancestral maps and linguistic distribution maps of different periods can serve as historical evidence for racial migration and linguistic transfer. But if either one has incorrect or inadequate data, its historical value has to be carefully evaluated. This paper sets out to talk on Naoyoshi Ogawa's A Map of Linguistic Distribution of Taiwan (1907), and then discuss the ways of appraising the historical value of racial or linguistic maps, and the possibility of reconstruction of historical facts.