Contacts:
PI Daniel I Goldman (daniel.goldman@physics.gatech.edu)
Perrin E Schiebel (perrin.schiebel@gatech.edu)


All data handling was initially done in MATLAB using .mat files. 
We have also included data sets as .csv to ensure accessibility.

Data collected in 2016 at Georgia Tech, Atlanta, GA, USA


***Positions***

Each .csv contains the X or Z positions of the snake midline for a single trial.
X and Z are provided in separate folders: the trial numbers coincide.

A single .csv contains an nt x 100 matrix.

nt are the number of tracked frames from that trial
The 100 data points in each row represent the x(z) coordinates of the midline of the snake at that time.


The folder labelled as NoPosts is the data from trials when no posts were present in the arena.


Snakes were tracked using the function "trackAllShagVideosTFB.m" which calls "trackSnakeInVideoOnShagNewTFB.m" found in Codes.zip 
Raw data are black and white .avi files reporting RGB values for each pixel.
These are converted to in the code.
Further description of tracking and analysis may be found in the SI Appendix.

.mat files contain the raw tracking data in "xSort" and "ySort" and the data used in subsequent analysis "splineX" and "splineY".
"angles" and "kappas" are the angle relative to the array before contact and the radius of curvature of the trajectory after exiting, respectively.
These .mat files are the output of SnakeRunSortingShagv3.m


***Forces***
Each .csv is data from a single trial

Forces are reported for the pair of posts the snake passed between. 

Forces are in a matrix 4 x nt
where nt are the number of frames during which the tracked snake points are within the array.

Each of the 4 rows are 
1: Post 1 force in x
2: Post 1 force in z
3: Post 2 force in x
4: Post 2 force in z

Note that the ordering of the posts has no significance in the current study. Post 1 is assigned to be the post that the snake is closest to on average. 
We did not use this information nor the order of the posts (1 vs 2) in our analysis.


The code used to determine the post pair and passage time is in the Codes .zip. "SnakeForceHistogram_syncRuns_052617.m"

The force .mat files are labelled with the trial name and _ForceX, _ForceY for forces in the Z and X axes as labelled in the paper, respecively. Each file contains a 7xnt matrix (some have only 6 tracked posts, this does not affect any analysis as trials were the snake passed outside the array were not included). This is the force data for each post through time.
Note that the time in these matrices does not necessarily match that in the kinematics as only times were the snake was within view of the post camera were saved and tracked.

%%%Morphological measurements%%%

The SnakeMorphologicalMeasurements_ScatteringPaper.xlsx contains twosheets
The first, Body Widths contains the width of the snake, measured by hand from a photograph, at each of the black bands on the body (incuding all bands).
The second, Snake Lengths and Masses, are length and mass measurements for all snakes used in the study.