Chi elevation profile provides a measure of equilibrium condition of watershed. To obtain this, Qina has been manually selecting a specific polygon from the shape file and elevation information from DEM data (Geotiff file) to generate a clip file in ArcGIS. To do chi analysis, it is passed through a tool named chi analysis tool written in C++, which is an open source in CSDMS (http://csdms.colorado.edu/wiki/Model:Chi_analysis_tools).

Below is the online document of how to use the tool to calculate chi.
http://www.geos.ed.ac.uk/~smudd/LSDTT_docs/html/index.html
After going to the web, click 7. Chi analysis: part 1: getting channel profiles and 8. Chi analysis: part 2: extracting the m/n ratio and performing the chi transformation from the content.

It consists of two parts.
Part 1
1.Download your DEM.
2. Project it into a projected coordinate system (we usually use UTM).
3. Export the DEM in .flt or .bil format. See Data preparation 2: Notes for using GDAL to manipulate files for LSDTopoToolbox .
4. If the programs aren’t complied, make them with: chi_step1_write_junctions.make and chi_step2_write_channel_file.make
5. Run the program chi1_write_junctions.exe on your DEM.
6. Import the junction raster (.JI.flt) into a GIS and pick a junction (this is easiest if you also import the stream order (_SO.flt) and hillshade (*_HS.flt).
7. Run chi2_write_channel_file.exe to get the .chan file.

Part 2
http://www.geos.ed.ac.uk/~smudd/LSDTT_docs/html/chi_analysis_part2.html#a-sample-chi-analysis-workflow