Requesting Data as a Collaborator

The consent document for e-mission ( allows the platform owner (@shankari in this case) to share de-linked raw data with other collaborators for research.

Time-delayed subsets of individual trajectory data, associated with their UUIDs but not email addresses, may by shared with collaborators, or released as research datasets to the community from time to time. If this is done, the time delay for sharing with collaborators will be at least one month, and the time delay for releasing to the community will be at least one year. Both collaborators and researchers will be asked to agree that they will publish only aggregate, non personally identifiable results, and will not re-share the data with others.

It also allows other researchers to use it to conduct studies. In this case, all data, including the link between the email address and the UUID will be made available to the researcher.

If this platform is being used to collect data for a study conducted by another researcher, for example, from a Transportation Engineering Department, then you will be asked to assent to a separate document outlining the data association, retention and sharing policies for that study, in addition to the policies above. We will make all data, including the mapping between the email address and the UUID, directly available to the lead researcher for the main study. This will allow them to associate the automatically gathered information with demographic data, and any pre and post surveys that they conduct as part of their study. The other researcher may also choose to compensate you for your time, as described in the protocol document for that study.

This document provides the procedure to request access to such kinds of data. Most of the procedure is common; differences between them are labelled linked and de-linked.

Setup GPG

We will send and receive data encrypted/signed using GPG. 1. The steps for creating a GPG keypair are at 1. Create a keypair and export it. 1. Send me (@shankari, the public key via email.

Data request


Next, you need to formally request access by filling out a pdf form.

  1. I will send you an encrypted version of the form you need to fill out and a copy of my public key.
  2. Decrypt it using
  3. Fill it out and sign it physically.
  4. Also sign it electronically
  5. Encrypt it using my public key and send it to me

If all of this works, we know that we have bi-directional encrypted communication over email. Make sure to encrypt any privacy sensitive information (e.g. subsets of data for debugging) that you send to me in the future.


You need to send me a copy of your IRB approval and your consent document to ensure that you have permission to collect data.

Data retrieval


  1. As you can see from the consent document, you can get access to data that is time-delayed by 1 months.
  2. I will upload an encrypted zip file with ~ 3 months of data to google drive and send you a link.

Note that this data is very privacy-sensitive, so think through the answers carefully on the request form carefully and make sure that you follow them. Treat the data as you would like your data to be treated.


  1. I will upload an encrypted zip file with all your data to google drive and send you a link.


  1. You need to decrypt it just like you decrypted the pdf form
  2. When unzipped, the data consists of multiple json files, one per user.
  3. The data will typically contain both raw sensed data (e.g. background/location) and processed data (e.g. analysis/cleaned_trip)
  4. Data formats for the json objects are at emission/core/wrapper (e.g. emission/core/wrapper/ and emission/core/wrapper/

Data analysis

While it is possible to analyse the raw data, it is large, so you may want to load it into a database to work with. That will also allow you to write code that is compatible with the server, so that we can more easily incorporate your analysis into the standard e-mission server.

Install the server

Follow the README and install e-mission server locally on your own laptop.

Load the data

Load the data into your local database. Since this data contains information from mutiple users, and you presumably want to retain the uuids, to correlate with other surveys that you might have performed, you should use the script. Since there are multiple files, the timeline will typically be a directory, and you should pass in the prefix. For example, if the user files are all_users_sep_dec_2016/dump_0109c47b-e640-411e-8d19-e481c52d7130, all_users_sep_dec_2016/dump_026f8d13-4d7a-4f8f-8d35-0ec22b0f8f8b, ..., you should run the following command line.

./e-mission-py.bash bin/debug/ all_users_sep_dec_2016/dump_

Linked data ONLY

You can load the email <-> UUID mapping also into the database by using the -m MAPFILE option (see below). In this case, the mapping will be loaded into the get_uuid_db() similar to the regular server. If you don't specify the -m option, then the users will be loaded with dummy names - user001, user002 ... - and you can manipulate the mapping json file directly to find out their email addresses.

./e-mission-py.bash bin/debug/ -m all_users.json all_users_sep_dec_2016/dump_

Run the pipeline

As discussed earlier, downloaded timelines typically contain analysis results, so there is no need to re-run the intake pipeline. The script will automatically detect this and print the following line.

timeline contains analysis results, no need to run the intake pipeline

If they do not contain analysis results, the script will print the line

all entries in the timeline contain only raw data, need to run the intake pipeline

In that case, you should run the intake pipeline (bin/ to get the processed analysis results.

Clean up the loaded data

You can also remove the data by using bin/, which will delete everything, or bin/debug/, which will only delete the entries in that timeline - e.g.

./e-mission-py.bash bin/debug/ all_users_sep_dec_2016

Play with the data

An example ipython notebook that shows data access parameters is at It has examples on how to access raw data, processed data, and plot points. Please use the timeseries interfaces as opposed to direct mongodb queries wherever possible. That will make it easier to migrate to other, more scalable timeseries later.

Again, data formats are at Let me (@shankari) know if you have any further questions...