Wednesday, 6 September 2017

The wrong way to upgrade a Cloud Platform

The need for upgrading a platform that hosts cloud services and applications derives from a variety of pretty good reasons.
  • There are always improvements that you may apply in the structure and architecture of your platform
  • Faster more intelligent and more reliable algorithms and procedures will benefit your cloud performance; so you should upgrade
  • A modern cloud infrastructure must support modern technologies; so you have to upgrade
  • As time goes by, clouds become bigger their services are delivered faster and their users are increased; you your cloud has to manage the extra burden
  • If you don’t consider the above and you do no upgrade your platform will become useless in a while
Let’s suppose that you have decided to upgrade and you also have set the specifications and goals of your upgrade. There is a key issue on applying the necessary changes. This is backward compatibility. In simple words, you have to answer the question “How easily the users and applications of the previous version of my platform will adapt to the new version?”.
This is not an easy question to answer and depends on how big the upgrade will be. There are cases where upgrades are almost invisible as the architecture of the platform does not change dramatically and the hosting specifications stay the same and on the end no-one notices any change. There are also case where the change is quite big to miss. Usually old architectures become useless after some time and an upgrade has to be like building the platform from scratch.
In case of the second category, the administrators of the platform have to design an easy and as possible less painful way for users, developers and applications to migrate. Give the developers and users some time to understand the new platform. Keep both versions running in parallel for an efficient amount of time. Give the developers and users a good and clear deadline for migrating to the new version and make sure this migration will be feasible within this time.
Another important issue is the terms of use and the pricing policy of the new version. In case of incompatibility between the terms of use of the two versions or in case of radical changes in the pricing policy then the users will have to migrate to a new version of the platform that does not satisfy them or their needs any more. Moreover it is, at least, not decent to trap your old clients that have invested in your platform into a new version that does not satisfy their needs any more, constrains them and makes them spend more.
This is exactly what happened with Open Shift the cloud platform of Red Hat. A new promising version of the platform was recently released (version 3) and Open Shift made in short an important announcement. The architecture of the platform has changed so you have to adapt to it the architecture of your apps; the pricing policy has change, to more expensive, so reconsider your budget; you have one month to upgrade.
It sounded like a joke but it was true. One month is a short period of time to adapt to a new architecture. Reading the terms and conditions while signing for version 2 it was clearly written that the pricing policy would not change. We all thought that this would be for the whole platform; I think they meant to write that this would be only for the current version. After lots of complains the deadline was extended to four months only for the customers that had sighed on a paying plan.
Still, this is not a serious and professional way to upgrade a popular cloud platform.

Tuesday, 18 April 2017

Indexing and publishing web maps maps provide a useful and interactive experience in map handling and this along with the rich available content they offer justifies their extensive spread on the internet. Despite this fact, the protocols that the operation of web maps is based on are not directly supported by internet browsers so additional software is usually required for accessing web maps.
The most popular open web map protocol is WMS and it is used in web sites along with libraries like OpenLayers or Leaflet to support its operation. In order to index web maps or perform general purpose mapping operations, users should either use GIS packages like QGIS or Global Mapper which are desktop applications with limited portability capabilities or turn to applications like ArcGIS Online with restricted usage and subscription based access.
WMS Map Viewer on line is an http/JavaScript general purpose application for accessing and indexing web maps. The application is provided as SaaS (Software as a service) so that the necessary software required for managing web maps is rapidly loaded while accessing the web site of the app. Then the users may open the maps of their choice by simply entering its URL and layer name or choose from a list of preconfigured connections to various map sources.
The application is freely accessible without needing to create an account or subscribe. Also, it is compatible with all modern versions of the WMS protocol providing easy access to any web map. There are also other interesting built-in features like the ability to overlay map layers over other open maps enabling the composition of multilayer maps; the ability to open and display .kml file; the function of drawing on the maps and outputting the drawings as point, line or polygon .kml files.
An important feature of the app that empowers portability is the ability to store all open map layers in a single file that users may share and view from anywhere. The save & share feature is accessible as an option from the Tools drop down menu or from the Layers button. Using this feature the map layers that the user has open are saved in an .html file which contains all the information to load them again on the same or any other device desktop or mobile.
So, the saved .html files may be posted, shared or published on line as part of a website. Accessing the files from any device will open WMS Map Viewer on line with all the layers loaded as they were saved. These features make this application ideal for indexing, sharing and publishing sets of web map layers as third-parties may access and display the map without installing extra software everything will be loaded after double clicking (or tapping) on the .html file.

Saturday, 10 December 2016

Create files with Javascript

In web apps (the new trend is to call them progressive apps) it is often useful to create files on the fly. On this I talk about creating files on the user’s computer by executing some piece of code on the user’s browser and then let the user view them and even store them locally. The other alternative is to create files on the cloud so that the user may then download them, but sometimes this is not necessary. So let’s see how this can happen by placing a few lines of Javascript code on the web app.
The following example regards creating text files from text that is inputted by the user. For this we need a web page with basic formation and a textarea with id=”input” where users may type whatever they wish. Then some function that creates a file from input. And finally a function that makes the file downloadable.
The makeTextFile function creates the file on text input. At first it creates a null variable named textFile which will become the text file. Then a Blob named “data”. A blob is an object of immutable data (text or binary) that may be used like a file and Javascript uses blobs in order to manipulate files; in some cases this technique is used in order to prevent direct access of a script to the file system. You may create blobs containing binary or text data but in this example we focus on text files so our blob is of type 'text/plain'. Next step is to create a URL pointing to the blob using function URL.createObjectURL.

var textFile = null;
function makeTextFile (text) {
    var data = new Blob([text], {type: 'text/plain'});
    textFile = URL.createObjectURL(data);
    return textFile;

Function txt() that follows stores user input in variable textbox which will then be the input of makeTextFile function. Then the link with id=”downloadlink” of the web page is declared to point to the output of makeTextFile function. So by clicking on the link, user input is downloaded as a text file.

function txt() {
    var textbox = document.getElementById('input');
    var link = document.getElementById('downloadlink');
    link.href = makeTextFile(textbox.value);

Find the full source code of the above example in this link. In order to make this example I used various sources and examples from the web so there is no ownership on it; in other words “use it as you wish”.

Saturday, 29 October 2016

Zombies and other freaks in GIS workplaces

In the past, in certain jobs and certain offices I had the sense that I was surrounded by zombies and freaks.
It seems I 'm not the only one to have had such experiences. Read this post by which I can't decide if it is funny or horrifying serious.

Wednesday, 24 August 2016

Maps are better displayed on big (TV) screens

TV sets these days have become more powerful than ever. They are equipped with powerful operating systems like Android and WebOS and their screens seem more magnificent than they could ever be. So why not to use them for map display?
Maps contain information related to spatial data and it is always better to view them with a big clear view of the spatial information they carry. For instance, sometimes it is not so informative to view a generalized weather map in the small screen of a smartphone; a big screen or printing the map in a big paper give you a clear insight of the situation it represents. Also a school could use a set of digital maps for educational purpose rather than using a few printed maps not viewable from distance.
Of course professionals know these things and the use big computer screens for drawing maps but most other people use small screens even at home. Personally, I always thought that TV screens could have much more potentials beyond their traditional use. On this spirit I have released two applications that link viewing my web mapping application WMS Map Viewer On Line to Android TV and Amazon TV. The result is really great try it.

Play Store link

Amazon Appstore link