Three year summary Lake Geneva

Notebook 1

Purpose: Present an analysis method for survey results from beach litter inventories on Lake Geneva.

Background: This is in the context of the global movement to reduce plastic debris in the maritime environment. Riverine inputs are major contributors of plastic debris (and all types of refuse) to the oceans. This is an analysis of the data collected on the shores of Lake Geneva over a three year period. The maritime protocol was modified in very specific ways to adjust for the local geography and population density.

Research question: Is this a representative sample ?

There is a push to quantify the amounts of plastic trash in the environment. It would be impossible to pick up every piece of trash in the environment and count it (that would solve the problem though). Extrapolating from economic and population data is one way to obtain a macro-view of the problem. But the margin of error on these type of calculations makes them unsuitable for identifying trends on a local or regional level.

If sampling all the trash is not possibile, what if we sample as much as possible and see what that looks like? The following questions could be answered:

  1. What does the distribution of survey results look like?
  2. Do different groups of people produce different survey results?
  3. How different are the survey results from one location to another?
  4. What are the most abundant objects?
  5. How different are the survey results year over year?

These series of notebooks will try to answer those questions.

Imports, setting up directory, getting data and storing locally

Directory already in place

Grouping and sorting

Extract some general descriptive statistics from all samples. Then group the data and compare the individual group results to the all the data.

  1. Group by date ranges
  2. Group by code => location
  3. Group by project
  4. Group by municpality

Read in the json data

Make pcs/m, make grouping levels

Results: Number of samples, sample locations, profile of participants...

Samples grouped by participants

There were/are many groups on the lake shore concerned by this problem. The data originates from five distinct groups:

  1. Students from École interantionale de Genève
  2. Students from The EPFL Solid waste engineering course
  3. Members of the World Wildlife Fund and or STOPPP
  4. Members of hammerdirt
  5. Members of Precious Collect Léman

How are the observations similar or different when sorted by group membership? The sampling method and conditions leave alot of responsibiliyt to the sampler. What a persons "sees" and how fatigue and environmental conditions effect an individuals attention to detail and motivation are variables that are part of the sampling process.

Following a protocol and educating surveyors should minimise the effects of those variables. None the less the effects are real and they may have an impact on the results.

All data Nov 2015 - Nov 2018

Year one Nov 2015 - Nov 2016

Year two Nov 2016 - Nov 2017

Year three Nov 2017 - Nov 2018