Analyzing Water Contamination with ArcGIS

For my thesis, I conducted a case study on Mexico's water contamination levels, focusing on arsenic concentrations, and created visual maps using ArcGIS software to aid in the interpretation of the data. Below is the process I followed to build the maps:

1. Data Collection: The first step involved navigating the website https://www.gob.mx/conagua to find surface and underground water data, which was essential for the analysis.

2. Research Tool: Discovered a free online tool called MyGeodata Converter, which allows data format conversion to GeoJSON, compatible with ArcGIS Online. 

3. Convert KMZ to GeoJSON: Used MyGeodata Converter to convert the original KMZ file into GeoJSON format for use in ArcGIS Online, avoiding limitations with KMZ files.

4. Upload to ArcGIS Online: Added the converted GeoJSON file to ArcGIS Online as a hosted feature layer for further analysis.

5. Data Selection: Changed the output data to GeoJSON type and selectively unselected certain input data layers to focus on relevant ones.

6. Threshold Grouping: Grouped Arsenic level values into thresholds for analysis:

• <0.01 (EPA standard)

• 0.01-0.03 (2x standard limit)

• 0.04-0.09 (4x standard limit)

• 0.1 (Very high levels)

7. Color Coding Issue: Encountered difficulties with color coding in ArcGIS Online. The gradient did not work as expected, with colors repeating instead of transitioning from green to red, and the values (over 1,000 entries) were difficult to manage.

8. Desired Solution: Sought a more efficient way to color-code the data, possibly by grouping values and applying corresponding colors.

9. Text to Numeric Data Conversion: Faced a new challenge of converting text data into numeric data in ArcGIS Online for better analysis and visualization.

Data Files

Obtained from and are added below.

https://www.gob.mx/conagua