请教：OG第45篇一句话的意思~~

ysl246

Maps made by non-Native Americans to depict Native American land tenure, resources andpopulation distributions appeared almost as early as Europeans’ first encounters with Native Americans and took many form: missionaries’ field sketches, explorers’ drawings, and surveyors’maps, as well as maps rendered in connection with treaties involving land transfers. Most existing

maps of Native American lands are reconstructions that are based largely on archaeology, oral reports, and evidence gathered from observers’ accounts in letter, diaries, and official reports;accordingly, the accuracy of these maps is especially dependent on the mapmakers’ own interpretive abilities.

Many existing maps also reflect the 150-year role of the Bureau of Indian Affairs (BIA) in administering tribal lands. Though these maps incorporate some information gleaned directly from Native Americans, rarely has Native American cartography contributed to this official record,which has been compiled, surveyed, and authenticated by non-Native American
                

. Thus our current cartographic record
                        relating to Native American tribes and their migrations and cultural features, as well as territoriality and contemporary trust lands, reflects the origins of the data, the mixed purposes for which the maps have been prepared, and changes both in United States government policy and in non-Native Americans’ attitudes toward an understanding of Native Americans.

红色部分那句话什么意思？后面的which从句到底是修饰谁的？到底是说information gleaned directly from Native Americans可靠还是不可靠呢？

. Thus our current cartographic record
            relating to Native American tribes and their migrations and cultural features, as well as territoriality and contemporary trust lands, reflects the origins of the data, the mixed purposes for which the maps have been prepared, and changes both in United States government policy and in non-Native Americans’ attitudes toward an understanding of Native Americans.

红色部分那句话什么意思？后面的which从句到底是修饰谁的？到底是说information gleaned directly from Native Americans可靠还是不可靠呢？

jasoncz1

Though these maps (官方的), incorporate some information gleaned directly from Native Americans, rarely has Native American cartography(印第安人的地图信息) contributed to this official record(官方的),which(对于官方的来说) has been compiled, surveyed, and authenticated by non-Native American.  这意思是说官方的地图大多数都是不是本地人自己造的, 这地图里很少有当地绘图人的贡献, 所以是不可靠的.

ysl246

以下是引用jasoncz1在2007-7-4 13:01:00的发言：

Though these maps (官方的), incorporate some information gleaned directly from Native Americans, rarely has Native American cartography(印第安人的地图信息) contributed to this official record(官方的),which(对于官方的来说) has been compiled, surveyed, and authenticated by non-Native American.  这意思是说官方的地图大多数都是不是本地人自己造的, 这地图里很少有当地绘图人的贡献, 所以是不可靠的.

thx a million!!