csapi with multiple consecutive coordinates

My x,y data is in the following format. Basically I have separate lines, but all the x and y are in the same array.

0	-15.6434352099231
0.0993194000787092	-16.0154142771549
0.198638800157418	-16.1980660624796
0.292335074968857	-16.0367986149356
0.386031344158518	-15.6270128679105
0.479727618969956	-15.3230394016863
0.579047019048666	-15.3221427866024
0.678426923997697	-15.4457363459043
0.777806828946728	-15.5349466895620
0.851871220779107	-15.8151654343951
0.925935608167622	-16.0956878582673
1	-16.1980660624796
NaN	NaN
0	-15.3365041384341
0.0993194000787092	-14.8688490307282
0.198638800157418	-14.5851836920701
0.292335074968857	-14.7051627633113
0.386031344158518	-14.9423031670397
0.479727618969956	-14.9377721995851
0.579047019048666	-14.9270476491485
0.678426923997697	-15.1172369876827
0.777806828946728	-15.2044753223834
0.851871220779107	-14.9222557245268
0.925935608167622	-14.6532254842178
1	-14.5851836920701
NaN	NaN

When I try to plot the spline, the results do not make much sense:

cs = csapi(X,Y);
fnplt(cs);