Update README.md

README.md

@@ -46,18 +46,16 @@ The structure of "./data/raw/" should be like:
 road-network/roads.csv records the road network of the five cities.
 
 
-data_with_trajectory_20s/* records the trajectory of courier every 20 seconds.
+data_with_trajectory_20s/* records the trajectory of courier.
 ```python
 import pandas as pd
 >>> import pandas as pd
 >>> df = pd.read_pickle("courier_detailed_trajectory_20s.pkl.xz")
->>> df.head(5)
+>>> df.head(3)
     ds                        postman_id        gps_time           lat           lng
 0  321  106f5ac22cfd1574b196d16fed62f90d  03-21 07:31:58  3.953700e+06  3.053400e+06
 1  321  106f5ac22cfd1574b196d16fed62f90d  03-21 07:32:18  3.953700e+06  3.053398e+06
 2  321  106f5ac22cfd1574b196d16fed62f90d  03-21 07:32:41  3.953700e+06  3.053398e+06
-3  321  106f5ac22cfd1574b196d16fed62f90d  03-21 07:55:51  3.953700e+06  3.053398e+06
-4  321  106f5ac22cfd1574b196d16fed62f90d  03-21 08:31:42  3.953929e+06  3.052367e+06
 ```
 
 Each sub-dataset (delivery, pickup) contains 5 CSV files, with each representing the data from a specific city,  the detail of each city can be find in the following table.