OpenLayers : A great plug-in to display Google Maps (and others) in QGis

I just found a plug-in extension for QGis that would allow me to  add a number of image services to your map canvas :

Installing the Plugin

The OpenLayers plugin is installed like all other Python plugins. From the the Plugins menu in QGIS, choose Fetch Python Plugins. This brings up the plugin installer. To find the plugin, enter openlayers in the Filter box, then select OpenLayers Plugin from the list. Once it’s highlighted, click the Install plugin button. This will download the plugin from the repository, install it, and load it into QGIS.

 
Using the Plugin

The OpenLayers Plugin uses your view extent to fetch the data from the service you choose. For this reason you should load at least one of your own layers first. Since each of the services are expecting a request in latitude/longitude your layer either has to be geographic or you must enable on the fly projection.

To add one of the services you have two choices; you can pick the service from the Plugins->OpenLayers plugin menu or you can use the OpenLayers Overview. The Overview opens a new panel that allows you to choose a service from a drop-down list. Click the Enable map checkbox to enable the drop-down list and preview the service you want to add. If you are happy with what you see, you can add it to the map by clicking the Add map button.

Download :http://plugins.qgis.org/plugins/openlayers_plugin/

How to connect spatial database(PostGIS) with QGIS?

In this section, I am showing the 3 basic steps to connect PostGIS database with a widely used open source desktop based gis, QGIS. 

Step1: Install PostGIS with Spatial database support extension

• If PostgreSQL is already installed è Launch ‘Application stack builder’ from startup menu in windows 7.
• Select the appropriate instance of PGSQL from dropdown list and Click NEXT.
• Expand ‘Categories’è Expand ‘Spatial Extensions’ è Select appropriate PostGIS version(1.5)  for the already installed PGSQL version(8.4).
• Follow the instructions to install the PostGIS extension.

Step2:  Loading spatial data into PostGIS

• Open the PgAdmin window (above installation should install a ‘Shapefile to PostGIS importer’ plugin.)
• Select the database and click on ‘Plugins’ and select ‘Shapefiel to PostGIS importer’ plugin.
• If the plugin is not available under the ‘Plugins’. We can also get it from “C:\Program Files (x86)\PostgreSQL\8.4\bin\postgisgui\shp2pgsql-gui.exe”

• Select the desired shp file to put into PostGIS.
• We need to put the appropriate SRID for the imported file. SRID column contains datum information of the imported shapefile into the PostGIS. There are unique SRID for the different projection and datum types.
•  Above step feeds the spatial information into the database with two additional fields, one for vector geometry id and another for vector geometry with datum information.

Step3:  Retrieving spatial data from PostGIS into Web based applications and Desktop based applications.

• We can view and project above data using Qgis(An open source GIS alternative to ESRI’s ArcGIS) in desktop based environment. Similarly, we can use Geoserver or UMN Mapserver view data in the Web.
• The core technologies behind Qgis and GRASS are similar. Qgis is easy to use, support GDAL, Python, PostGIS, and has nice GUI. In the same time we can get strength of GRASS by calling GRASS’s functionality form   the QGIS. 
• Install Qgis 
• Open the Qgis --> Click layer--> select ‘Add from PostGIS’, which gives you the following windows.

•  Click connect, you should able to see the shape layer as below.

• Finally you will able to see the vector layer in the layer and this layer can be treated as an ordinary shp. file added in the ESRI ArcMap.

Free Remote Sensing Software :OPTICKS 4.10.0

Opticks is an expandable remote sensing and imagery analysis software platform that is free and open source. If you are interested you can learn about the history of Opticks.

If you've used commercial tools like: ERDAS IMAGINE, RemoteView, ENVI, or SOCET GXP, then you need to give Opticks a try. Unlike other competing tools, you can add capability to Opticks by creating an extension. Opticks provides the most advanced extension capability of any other remote sensing tool on the market.

Feature:

• Free and open source
• Supports the following file formats: NITF 2.0/2.1, GeoTIFF, ENVI, ASPAM/PAR, CGM, DTED, Generic RAW, ESRI Shapefile, HDF5, AVI, MPEG, JPEG, GIF, PNG, BMP
• Zoom, pan, rotate spatially large datasets
• Quickly layer GIS features, annotations, results, and other information over your data to provide context
• Many image display controls such as colormap, histogram, transparency, etc.
• Support for datasets larger than four gigabytes
• Analysts can quickly combine steps using graphical wizards
• Support for processing data in its native interleave of BIP, BSQ or BIL
• Get extensions to drop in new capability.

Download :

http://opticks.org/confluence/display/opticks/Download

Download gvSIG

gvSIG is a project dedicate to geomatic science. Download gvSIG free and you will be able to obtain and analyze geographic information in a very precise way

Download gvSIG

QGIS Tutorials

Intersting tutorial from Harvard :    QGIS Tutorial

  Beginning QGIS Tutorial

Free and Open Source GIS Resources

• News about free and open source GIS
  
  • http://www.digitalearth.ca/
• Free and open source software sites specific to GIS
  • http://freegis.org/
  • http://www.maptools.org/
  • http://www.remotesensing.org/
• Free and open source software sites that include GIS
• http://sourceforge.net/index.php
• http://www.freshmeat.org/

Bundled Software

Sometimes it's just easier to go one place. Here are some places worth going.

FWTools http://fwtools.maptools.org/

Frank Warmerdam maintains most of the open source infrastructure for handling projections and file formats. It's handy to know what and where they are, since they are often prerequisites for installing other packages: proj4 and GDAL (pronounced "goodle", rhymes with noodle).

FWTools includes pre-compiled binaries for both Windows and Linux of GDAL and proj4, along with the web map server MapServer and raster-oriented desktop OpenEV. Frank contributes to or maintains all these packages.

GIS Knoppix http://www.sourcepole.com/sources/software/gis-knoppix/

GIS Knoppix is a self-booting Linux CD set up to be a sort of Linux workstation on a CD. It has office productivity tools, like OpenOffice , along with a full set of GIS tools: desktop, web map server, etc.

MapServer for Windows (MS4W) http://www.maptools.org/ms4w/index.phtml

MS4W installs pre-compiled windows binaries that comprise a complete development environment for making applications with the MapServer web map server.

Enterprise GIS: Spatially Enabled Databases

PostGIS http://postgis.refractions.net/

PostGIS is the most commonly used back-end database in free software. Most of the desktops listed are PostGIS clients, as well as the MapServer and GeoServer web map servers.

MySQL http://www.mysql.com/

MySQL has spatial extensions , and is supported in both the MapServer and GeoServer web map servers.

Desktops

GRASS http://grass.ibiblio.org/index.html

GRASS , the Geographic Resources Analysis Support System, is a long-standing, complete GIS system. It was originally written in Unix, and runs best in Linux or Unix of some kind. Although the interfaces have recently improved it still has a learning curve. The GRASS community is enormous, and world-wide, with commensurate support resources.

JUMP http://www.jump-project.org/

JUMP supposedly works everywhere, but is much more windows oriented. Has a nice graphical user interface (GUI), and includes conflation tools. It requires SUN's Java Virtual Machine (JVM).

OpenEV http://openev.sourceforge.net/

OpenEV is a raster-oriented viewer with some editing capability. Can display vectors, and create simple shapefiles. Most vector capabilities (snapping, etc.) are not present.

Quantum GIS (QGIS) http://qgis.org/

QGIS is mostly a viewer, with some fairly new editing capabilities. It is more mature on the Linux side of the house, but does have a windows preview release. It is extremely simple to operate, and creates configuration files for the MapServer web map server.

Thuban http://thuban.intevation.org/

Thuban is a viewer, and is definitely cross-platform (Windows, Linux, etc.). It's based on Python.

UDig http://udig.refractions.net/

UDig is still in development, but may suit your needs even in its current form. It's designed to expand on JUMP functionality, and conform to important Open Geospatial Consortium standards. Refractions Research is planning to sell support for uDig.

Web Map Servers

There are quite a variety of these. The two listed below have the most developed capabilities.

MapServer http://mapserver.gis.umn.edu/

MapServer has a very simple set-up and is economical with system resources. It is widely supported and integrated with other packages. The MapServer community has an annual conference.

GeoServer http://geoserver.sourceforge.net/html/index.php

GeoServer is Java-based, and has a fairly complex set-up. It is widely supported, and integrated with other packages.