为什么纳尼亚王国地图和原著中描写的不同？

关于《纳尼亚传奇：狮子、女巫和魔衣橱》原著和地图不同的疑问第一个问题：
地图上石桌在白女巫城堡的东南方，而书里写白女巫向西找过河的地方。
带上你手下跑得最快的狼，立刻到海狸家去。”女巫说，“不管你在那里发现谁，全都给我杀了。如果他们已经走了，那就全速赶去石桌，但是不要被人看见。在那里躲好等我。这期间我得向西走好几英里才能找到雪橇过河的地方。你大概能在那些人类抵达石桌之前追上他们。你也知道发现他们之后该怎么做！”
Take with you the swiftest of your wolves and go at once to the house of the Beavers,” said the Witch, “and kill whatever you find there. If they are already gone, then make all speed to the Stone Table, but do not be seen. Wait for me there in hiding. I meanwhile must go many miles to the West before I find a place where I can drive across the river. You may overtake these humans before they reach the Stone Table. You will know what to do if you find them!”第二个问题：

地图上贝鲁纳浅滩在阿斯兰营地的西侧，往白女巫营地方向。
书中写他们向东北走，还谈到了可以在对岸扎营可以防偷袭。
女巫一走，阿斯兰就说：“我们必须立刻离开这里，这地方另有他用。今晚我们在贝鲁纳浅滩扎营。”
As soon as the Witch had gone Aslan said, “We must move from this place at once, it will be wanted for other purposes. We shall encamp tonight at the Fords of Beruna.
在山顶的开阔处吃过饭后（那时已经艳阳高照，草地都晒干了），他们忙了一阵子，拆掉帐篷，打包物品。两点钟不到，他们便出发朝东北方前进，因为目的地不远，他们走得从容愉快。
After a meal, which was taken in the open air on the hill-top (for the sun had got strong by now and dried the grass), they were busy for a while taking the pavilion down and packing things up. Before two o’clock they were on the march and set off in a north-easterly direction, walking at an easy pace, for they had not far to go.

还不到傍晚，他们就来到一处河谷开阔，河面宽广，水也清浅的地方。这就是贝鲁纳浅滩，阿斯兰下令在这河的这一岸扎营。但是彼得说：
“到对岸扎营不更好吗？以防她试图在夜间偷袭之类的。”
It was still afternoon when they came down to a place where the river valley had widened out and the river was broad and shallow. This was the Fords of Beruna and Aslan gave orders to halt on this side of the water. But Peter said,
“Wouldn’t it be better to camp on the far side—for fear she should try a night attack or anything?”