Use ColorBrewer for coloring maps rendered with GeoTools

ColorBrewer is an excellent library for creating dynamic color palettes that can be used to apply colors to a map based on the spread of data values. The ColorBrewer web tool allows you to select a color scheme based on the nature of the data (sequential, diverging, qualitative) and  the number of data classes present in the data. You can opt to select a color scheme that is color blind safe and works well on a photocopier.
Based on your requirements, the web tool will display the name of the color scheme that works best for the entered combination. For example, in the screenshot below, the color scheme chosen by the tool is BuGn.

ColorBrewer 2.0

ColorBrewer comes bundled with GeoTools. To include the correct library,use the following Maven snippet.

     org.geotools
     gt-brewer
     2.7.2

To instantiate the required palette within your Java application,

   String paletteName = "BuGn";
  ColorBrewer brewer = null;
  try {
   brewer = ColorBrewer.instance(ColorBrewer.DIVERGING);
  } catch (IOException e) {
   //Log Error
  }
                // Instantiate the color palette 
                 palette = brewer.getPalette(paletteName);
                // Get the number of colors your need. In this case, 3 colors

                // which are a variant of Green
                 palette.getColors(3);

Now, you have an array of colors which you can apply to your GIS features.

India's upcoming tour of DownUnder 2011

The last time I put together my thoughts before India (the then Twenty20 World Champions) toured Australia, and predicted an exciting time, little did I realise that the tour would become infamous for all the wrong reasons. This time around, both teams have resolved to play cricket in the spirit that it is meant to be played. Michael Clarke will be leading a relatively inexperienced side against the one day World Champions who not so long ago where also the leading Test team. Both sides have a lot to prove. Clarke will be hoping to assert his leadership early in the series while the Indians will be hoping to go 1-up early.

The Boxing Day Test which will be viewed by about 60,000 fans at the MCG including myself will see Tendulkar, Dravid, Laxman and possibly even Ponting play a Boxing Day test for perhaps the last time in their long and illustrious careers.Lets hope that these stalwarts get the best possible opportunity to perform before an adoring legion of fans and we are treated to some superb cricket in the Boxing Day test and through out the series. I guess this series will in all probability see Tendulkar (barring an injury) get his 100th International hundred and it will be a well-deserved milestone that will perhaps stand the test of time, just like the Don's famous average of 99.94 will.

Addendum : The first day of the Boxing Day test was attended by 70,068 fans, a record for an India-Australia test match and the day lived up to its billing. Tough cricket was played out by both sides with neither willing to give an inch and the match looks headed for an exciting finish.Here are some pictures from day one of the test.

Install JFreeChart 1.0.14 with Maven

After 2.5 years, JFreeChart came out with a new release of the toolkit on Nov 21,2011.Version 1.0.14 promises bug fixes, improvements in the TimeSeries graphing and much more. Over the last few years, JFreeChart has been a popular open source choice for charts and graphs in Java.  The previous version has been download close to 430,000 times and while there are not many examples available describing the usage of the toolkit, installing it and implementing it in a Java application is relatively pain free.
Currently, the Maven repositories have not been updated with this release and you will need to manually install it into your local repository. To do so:

• Download the latest release from the source-forge download page. Unzip the jar onto your local file system to any directory, say C:\jFreeChart\jfreechart-1.0.14
• Open a command prompt in the directory where you have your Maven POM located and invoke the following command from the command line:
• mvn install:install-file -Dfile=C:\jFreeChart\jfreechart-1.0.14\lib\jfreechart-1.0.14.jar -DgroupId=jfree -DartifactId=jfreechart -Dversion=1.0.14 -Dpackaging=jar

This should install jFreeChart into your local Maven repository. Now you can add a dependency to the Maven POM as follows:

     jfree 
     jfreechart
     1.0.14 
     compile 
    

Tomcat 7.0, JSF (Mojarra) 2.3.1 and PrimeFaces 3.0M4

Spent the last few nights experimenting with the bleeding edge of Java Server Faces (JSF), Prime Faces and Tomcat and expectedly came away bloody and a lot more wiser.

Java Server Faces has come a long way in the last 5 years or so but a steep learning curve and relatively poor documentation makes it even harder to adapt. The latest specification release of JSF is 2.1, compatible with JavaEE 6 application servers, or any server implementing Servlet 3.0.JSF has two main implementation flavours- Apache MyFaces and Sun (now Oracle 's) Mojarra.

Now herein lies the problem.There are some subtle differences between JSF 2.0 and 2.1 specifications as pointed out by BaluC. JSF 2.1 is aimed at marrying the Servlet 3.0 API and so targets Servlet Containers supporting the 3.0 specification, such as Tomcat 7.0, Glassfish v3. while JSF 2.0 was aimed at the Servlet specification 2.5 and so works well with earlier releases of the servers.

If you are intending to use the latest release of Tomcat which is 7.0.22 and JSF MyFaces, you should be fine but if you try and bring in a component library such as Tomahawk, you'll find that support for the > JSF 2.0 version of a JSF implementation is not all there.I decided to use PrimeFaces and went with 3.0M4, a milestone release from last week and while the setup and integration of the stack (Tomcat 7.0.22, MyFaces 2.3.1 (and later I removed MyFaces and bought in Mojarra) was smooth(Thanks to Maven), getting the FileUpload component of PrimeFaces to work was impossible. The fileUpload bean would just not get called and there were no errors in the server log. Baffling!!Questions to the user forum did not show much light until I came upon Bug 49711 related to annotation scanning in the Tomcat archives. The problem was not with PrimeFaces of a JSF implementation but with a regression of Tomcat's handling of a multi-part request. This problem was reported since version 7.0.6 and while there is an indication that setting allowCasualMultipartParsing = true in the Context definition will by-pass this issue, I can tell you otherwise. Anyway, I got it all to work with Tomcat 7.0.2 (i.e I had to go back 20 releases).

Tomcat version 7.0 onwards implements the Servlet 3.0 specification and brings in some new and very much needed features such as out-of-the box authentication support(via the HttpRequest) and FileUpload. This major leap forward could have possibly led to these regression defects that need to be addressed before Tomcat can be regarded as a stable candidate for implementing a JSF based stack. JSF (MyFaces & Mojarra) doesn't really help Tomcat in the sense that itself is in a state of evolution and the component libraries are struggling to keep up.

To end on a positive note, I was very impressed by the PrimeFaces showcase and the extensive set of features offered which currently makes it one of the best JSF component libraries going around.However, again a word of caution.The last stable release of version PrimeFaces is 2.2.1 which has Flash based components while the latest 'milestone' version 3.0M4 is based on HTML5.This again is a major revamp of the architecture and currently the forum is littered with support questions and reports of 'not working', so wait for a few more releases before choosing PrimeFaces version 3+ or like me, prepare for battle!!