Recently, I was introducing Geographic Information Systems to my friends in college. We have something called the zeroth hour, which is an oppurtunity to stage knowledge sharing. I have been talking to my class mates regarding GeoHackers, and many of the projects which I am involved. Hence, thought of sharing some interesting things on GIS. The presentation is here.
I was speaking at the National Conference on Free Software held in CUSAT during November 15-16, 2008. The GNU HURD is the original kernel of the GNU Project. But, it lacked developers due to the extreme futuristic architecture. The GNU HURD is a MicroKernel, where the kernel performs only very basic tasks, and the rest are offered through deamons. You can get the presentation here.
The first Mapping Party in Kerala was held at National Institute of Calicut, Calicut, during 23-24 October 2009. The event was organized by the Free Software User Group Calicut and GeoHackers. Indeed the quality was poor. As a result of few discussions on the OSM emailing lists, I have been reworking with the data we collected. Added few new roads, paths etc. Making the map more rich. The map is here.
We had a very good experience learning more about OpenStreetMap and Mapping, through the NIT-C Mapping Party. Since then, we have been collaborating a google doc, to document the event. The How-to document is thus a part of the entire event, the geohackers initiative.
Map-making or Cartography aided mankind from the time when lived in caves, the geographic knowledge and the compass guided the progess of our civilization. Today such wealth is only available to those who can pay huge royalties or license fees. OpenStreetMap project (OSM) takes its inspiration from Free Culture philosophy and aims to provide geographic information of the entire planet to one and all.
Mapping parties are organized to teach map making skills and contribute to OpenStreetMap project. With the advent of GPS technology anyone with such a device and computer can build high quality maps. This document explains how one can organize a mapping party in their school or workplace.
Lets look the tools that are needed for making maps, we need a GPS devices, a personal computer to edit the mapping data and a account on OpenStreetMap servers to upload your data.
GPS is Global Positioning System. The earth is surrounded by 31 satellites, which provide us sufficient information to identify where we are on the planet. This tracking is processed with the help of geographic coordinates called Latitudes and Longitudes. There are lot of stand alone GPS receivers available in the market. At the mean time, most of the smart phones are equipped with GPS receivers. GPS devices are the primary data collection tool for mapping.
The data collected in the GPS devices are used in the GPX format. This is the most easy and efficient method for fetching the data from the device. The GPX file is the collection of traces and waypoints. Map images in formats like .jpg, .png etc are also used. The OSM data subsets are available in the .osm format.
Map editors are the workplace were we use the data collected from GPS to create the map. Creating the map involves proper tagging of the data. Many editors are available, like Java OpenStreetMap editor (JOSM), Potlatch, Merkaartor. Among these, JOSM is the heavy duty offline editor.
Getting an OSM account
We need to have a proper OSM account to validate and upload the map we created. You can create a new here.
Lets start mapping !
The next important step is creating teams. The entire party is divided into small teams based on how many GPS devices you have at your disposal and size of mapping area. Each team should have at least one person with good sense of direction. Each team can be given a name or colored arm band (optional). Each team is equiped with a terrian map with landmarks that show the borders of their sector. Various services like google, yahoo. walking-papers.org provide terrian maps that can be printed before hand. A person can act as a control center co-ordinator. He is responsible to staying in touch with team in the field with mobile phone or portable 2 way radio (optional)
Data Collection and Downloading
Maps are created at this stage. The data we have mined are ordered, analyzed, and tagged. We need to make sure that all the team follows a naming convention or comment. The coordinator should watch for over marketing / mis-marketing of the same location. Once the data is properly tagged, it is time to upload it to the OSM server.
Each team would be provided with a feedback form, which they are intended to provide sincere information regarding their experience in the workshop. This step is a sort of improvement and corrective measure for the GeoHackers team.
I have been having this trouble since I started to use my Internet connection using pppoeconf package. The thing is that, pppoeconf turns out to disable or override all other wired network.
This is the way to get it back in place:
1. Fire a terminal.
2. Type sudo gedit /etc/NetworkManager/nm-system-settings.conf
3. Now you should see something like this:
4. Change ‘false’ to ‘true’
6. Comment this post, whether this helped you or not.
Recently, I upgraded to the much awaited Karmic Koala from Jaunty. Experience with Jaunty was not so sweet. Anyways, thought to give a hand on Koala. Upgrade went successful. The only problem remaining was that I could not start voice or video chat using Pidgin. Koala comes with Empathy as the default client. But I never wanted to use that.
When ever I tried to start a voice chat I got the following error:
Error creating session: Could not create the rtp muxer element
Error adding stream.
This is just a trouble due to permissions to gstreamer and Farsight2. Follow the steps to get it right.
- Fire a terminal.
- Change directory to your home folder.
- Now type “mv .gstreamer .gstreamer.bak
- and “mv .farsight2 .farsight2.bak
We are moving the folders in order to be safe rather than deleting them, in case we need to restore them.