QGIS – OSM Connection

Quantum GIS is open source software available under the terms of the GNU General Public License meaning that its source code can be downloaded through tarballs or the git repository. This is written in c++ and has some libraries in Qt.

QGIS  is GIS application  with which you can you can mange, edit, or visualize your map. Infact this is wonderful tool with which you can make your map beautiful.

Now,as we know that our OSM data consist of Nodes, Ways and Relations. Here I must not forget to mention again “OpenStreetMap is a web-based map to which any registered user can submit data.”

Node is a a latitude/longitude pair of coordinates.  A way is a list of at least two nodes  describing a linear feature like street, or something similar. And third one Relation is used to specify relationships between objects. This relation isn’t much clear to me but one can look here for more information.

And in Quantum GIS, these are displayed as three separate layers: Point layer, Line layer and Polygon layer.
All three layers are equally important.

The data that lives on the OpenStreetMap can be downloaded and used inside of a QGIS for geospatial analysis,  rendering, and for other geo-related tasks.

Now,what is thing that makes connection between our Standout, dignitary OSM data and Quantum GIS ?

The QGIS OpenStreetMap Plugin, plugin for  QGIS, adds support for OpenStreetMap raw vector data, bring it in as a layer either from .osm XML file or by direct download from the OpenStreetMap API. With it you can even edit or upload back to OSM data.

 

Installing QuantumGIS in Ubuntu

One can install QGIS  either directly through Ubuntu Software Center or through terminal.

I did it through terminal. One just need to give four commands to install it.

 
gurpinder@gurpinder:~$ sudo apt-get install python-software-properties

gurpinder@gurpinder:~$ sudo add-apt-repository ppa:ubuntugis/ubuntugis-unstable

gurpinder@gurpinder:~$ sudo apt-get update

gurpinder@gurpinder:~$ sudo apt-get install qgis

 

Introduction to GIS

GIS is wonderful technology with great tools that help to grasp our data in better way.

GIS or Geographical Information System is a collection of software that allows you to create, visualize, query and analyze geospatial data.

You can say it is a computer-based tool for mapping and analyzing geographic phenomenon that exist, and events that occur, on Earth. Geospatial data refers to information about the geographic location of an entity. This often involves the use of a geographic coordinate, like a latitude or longitude value. One can perform variety of functions using geospatial data like computing distances between two points, or calculating particular area.

GIS has four main functional subsystems:

1. Data Input:  allows to capture, collect, and transform spatial and thematic data into digital form

2.Data Storage and Retrieval:  organizes the data in form which helps user to retrieve data easily

3.Data Manipulation and Analysis :  allows  to define and execute spatial procedures to generate derived information

4. Data Output : allows the user to generate graphic displays, normally maps, and tabular reports

Geospatial data is of two types: Raster data and Vector Data.

We can say that raster data is usually a digital satellite imagery or air photos. Raster data make use of grid-cell data structure where the geographic area is divided into cells identified by row and column.

Vector data is has some qualities which we studied in our trigonometry and coordinate geometry classes. Vector storage implies the use of vectors (directional lines) to represent a geographic feature. Vector data is characterized by the use of sequential points or vertices to define a linear segment. Each vertex consists of an X coordinate and a Y coordinate.

The range of GIS application is very large. You can use it for anything.

Take Crime Mapping. Mapping crime, using GIS, you can identify the crime hot spots. There are many similar examples where you can use GIS.

GIS is even useful to businessmen. One in Real Estate can make strong use of GIS.

Now,I must end with saying “GIS is just AWESOME “.