Cannot use rsgislib to do segmentation

[xfsm1912]

I installed the rsgislib 3.1.1225 in python 2.7 in mac. But I cannot use it to do segmentation. Here is my code:

from rsgislib.segmentation import segutils

but output is:

---

ImportError Traceback (most recent call last)
in ()
----> 1 from rsgislib.segmentation import segutils

/Users/Jianhua/anaconda/lib/python2.7/site-packages/rsgislib/segmentation/init.py in ()
36
37 # import the C++ extension into this level
---> 38 from ._segmentation import *
39 import warnings
40

ImportError: dlopen(/Users/Jianhua/anaconda/lib/python2.7/site-packages/rsgislib/segmentation/_segmentation.so, 2): Library not loaded: @rpath/libgeos-3.5.1.dylib
Referenced from: /Users/Jianhua/anaconda/lib/librsgis_cmds.1.1.0.dylib
Reason: image not found

can someone tell me what is wrong?