Monthly Archives: October 2016

Map Club — Dynamic Mapping with OpenLayers


The latest session of Map Club focused on OpenLayers, a high-performance library for rendering geographic information in the browser. OpenLayers enables users to visualize a diverse range of geospatial data formats, while offering intuitive links to external web-based mapping resources such as CARTO, OpenStreetMap, Stamen, and D3.js.

Participants explored OpenLayers functionality for importing KML and GeoJSON data, experimented with linking to different tile sets, and tried out the customizable interactive capabilities of the library in JavaScript.




From top: imported KML data, Stamen toner labels tile set, Frank Nitsche

Next week will be the second guided workshop of the semester. We will be digging into QGIS, a free and open source geographic information system that offers powerful tools for data editing, viewing, and analysis. Hope to see you there!

Sign up here if you would like to receive updates on future Map Club sessions. For this session’s resources and materials, visit the Map Club Github repository.

Python Open Labs – Session 5







Thanks for stopping by this post. In the 5th session of Python Open Labs, today we covered the concept of for loops in python along with a quick revision of concepts from the previous sessions. If you attended today’s session, I encourage you all to try out the practise problems from the slides on the google drive link given below.

Python Open Labs Slides:

A quick note about the course material:

  1. If you want to get set up with Python 2.7 installation on your system, check out the Session-1 slides.
  2. Practise! Practise! Practise!

Hope to see you next Friday, 11:00 AM at DSSC 🙂

Survey Documentation and Analysis (SDA)

Survey Documentation and Analysis (SDA) is a web based interface that allows access and analysis of data. The data can be accessed from IPUMS or from  the Inter-university Consortium for Political and Social Research (ICPSR).

SDA allows you to:

  • Browse the codebook describing a datasetsda
  • Calculate frequencies or crosstabulation (with charts)
  • Do comparison of means
  • Calculate a correlation matrix
  • Compare correlations
  • Perform multiple regression
  • Perform logit/probit regression
  • List values of individual cases
  • Recode variables (into public work area)
  • Compute a new variable
  • List/delete derived variables
  • Download a customized subset

SDA allows you to analyze data at a level appropriate to your level of experience. SDA can only analyze datasets that reside on an SDA server. If you would like to test drive SDA, or to see if SDA is useful for your research check out their General Information page.

R Open Labs – Data Manipulation

Today we introduced merge(), factor() and some basic techniques for handling missing values during the first 30 minutes of the open lab. For the rest of the open lab, there were free discussions about personal projects the participants are working on.


We also introduced package swirl. Swirl package teaches you R programming interactively.


Thank you to everyone who showed up! For next session, we would explore time series analysis and car package.


See you next Wednesday 10/26/2016 10:00-12:00! Welcome to drop by anytime in between!

Map Club — Interactive Maps with Mapzen


Last week, Map Club revisited Tangram, the powerful open-source renderer for Mapzen. (We first explored Mapzen over the summer.) Mapzen is an open, sustainable, and accessible mapping platform that offers intricate control over the design of web-based maps.

Centered on a map of Manhattan, attendees referenced the comprehensive documentation page to alter the drawing style of Tangram’s vector tile service. Tangram is connected to the OpenStreetMap database, and leverages OpenGL and shader language to enable mapmakers to fine-tune the visual effects of rendered data. The custom YAML syntax through which Tangram maps are styled provided a readable way of adjusting the visual attributes of the city in unexpected ways.



From top: Vibrant map by Rachael, animated water and building coloring using GLSL

There will be no Map Club session next Friday! The following Friday (10/28), we will be looking at OpenLayers, a high-performance library for rendering geographic information in web pages.

Sign up here if you would like to receive updates on future Map Club sessions. For this session’s resources and materials, visit the Map Club Github repository.

Python Open Labs Session – 3






Hi Everyone

Today in the third session of Python Open Labs we covered defining user functions, getting familiar with built-in functions, a quick revision of conditional statements and various ways and exercises to use functions and their advantages.

The course material from all Python Open Labs Session is available on Lion Mail Drive link:

I encourage everyone to look at the course material for quick revision of sessions and play around with the exercises to get a better hang of the things. Please feel free to reach out to me over email in case you require any clarifications.

See you next Friday 10/21/2016 at 11:00 AM 🙂
PS: Google drive link requires Columbia UNI login, in case you don’t have one please request on the drive link to grant access and I will do so.

R Open Labs – Plotting

Yesterday we briefly talked about how to do plotting in R. We mainly discussed plot(), barplot(), hist() and Lattice package. Thank you to everyone who showed up and we will explore more data visualization techniques for next session.

Also, from next session on, the open lab will be much less structured and will involve more discussion about personal projects, so people with different level of knowledge are welcome to join!

rplot rplot01

See you next Wednesday  10/19/2016 at 10:00 AM!

R Open Labs – Basic Syntax

Hi all, last Wednesday we kicked off the first session of R Open Lab in the DSSC( based in Lehman Library). We started with basic syntax and briefly discussed how to explore the features of our datasets. We used data from Wal-Mart and we will continue exploring this dataset for the next few sessions. Beginners are welcome to join!


See you this Wednesday  10/12/2016 at 10:00 AM!