Author: kostas

  • How to create JSON data from a text file on the internet

    The following assumes a linux command line to be present (or Mac OS X terminal in my case). I want to wrangle text from the internet, turn it into JSON data, and ultimately stick it in CouchDB. Here I’m trying to turn a random text file containing prime numbers into structured JSON data that looks […]

  • Who gains from blocked content on YouTube?

    When I want to hear a particular rap song from 1992 on YouTube, the video service shows me this: Yeah yeah, copyright or whatever, but what is the point? Who gains what exactly? By the way, if you can hear the song in the country you’re in, then fuck you :-) Who’s involved, let’s see. […]

  • Free online O’Reilly book on CouchDB

    http://guide.couchdb.org/

  • Using shp2geocouch to push OSM data into geocouch

    Today I installed the utility shp2geocouch on Mac OS X 1.6. First I needed to update RubyGems… sudo gem update –system Then I could install shp2geocouch sudo gem install shp2geocouch Next I downloaded OSM data for Copenhagen, Denmark wget http://download.cloudmade.com/europe/northern_europe/denmark/copenhagen/copenhagen.shapefiles.zip unzip copenhagen.shapefiles.zip cd copenhagen.shapefiles Finally I used shp2geocouch to upload one of the shape files […]

  • Installing spatial databases on EC2

    The spatial databases covered are PostGIS, MySQL spatial and MongoDB, Apache Cassandra. UPDATE: I’ll change this post or create a page to give the actual linux commands to run on the remote server. PostGIS on EC2 I have found a nice tutorial that describes setting up Postgres on EC2 on an Ubuntu instance with all […]

  • Opening and closing ports on EC2 instances

    Assuming that the EC2 tools have been installed like described in a previous post, opening and closing ports is done with the ec2-authorize and ec2-revoke commands respectively. These commands work on security groups rather than on instances. Recall that a set of instances belong to a security group. Opening port 80 on EC2 instances in […]

  • Hints for managing Amazon Linux on EC2

    I’m using Mac OS X and running instances in the EU West Region. My instances are of the Amazon Linux AMI. Installing the EC2 command line tools Having command-line tools installed is a supplement to the AWS management console found online. I found a good tutorial about how to get started with the tools for […]

  • Good indian computer science videos on youtube

    While browsing the web for for good videos to help me land a cool job at high profile tech firm, I came across this series from an Indian university. Lecture – 16 Disk Based Data Structures http://www.youtube.com/watch?v=VbVroFR4mq4 You should be able to easily find the other videos in the series through this one. Generally the […]

  • Image search by sketching – continued

    It’s a simple question Can you search for images by sketching a similar image? I went looking online for a search engine that had implemented this feature, which I’ll call image-search-by-sketching. Update: Since I wrote this piece, GaZoPa no longer exists. In the meantime Google has implemented image-search-by-image. You can’t sketch, but you can use […]

  • Image search by sketching in 2007

    This is a post in my technology archaeology series. What is search by sketching? The idea is to search for images by drawing a sketch that roughly resembles what you are looking for. The sketch is your query. This idea was mentioned in years 2007, 2010 and sometime in the late 90’s (according to my […]