Jornadas SIG Libre Girona VII

March 8, 2013 under SIG, Software Libre

The main theme of this Jornadas SIG Libre de Girona has been cloud services and open data. Since the apotheosic beginning, with an outstanding speech of Sergi Morales (ExportosenTI), the rest of the conference has been running around the same theme. Some of them maybe more critical, like the one of F. Puga from CartoLab when he asked us not to forget undevelopment zones where not everyone has internet access and millions  of people, which doesn’t have our tech level, also have GIS needs.

This is what cloud means on undevelopment countries. #siglibre7 #firstworldproblems

Anotheer interesting theme of this conference came by the hand of Malcolm Bain, who told  us about the legal limits of data cloud services, and what can we expect and demand and to what extent, from the cloud service provider, we have to offer a minimum service level. It is undoubtely surprising to learn that some of the contracts we accept on very well known services (like web mail or hosting) are, in fact, ilegal.

The battle of free software is ended, now we have to battle on freedom and privacy of data.

It has also been delightful to see the debate between some speakers, like when Javier de la Torre (Cartodbtalked against OGC or the government repositories of data. Undoubtfully a theme which, although I don’t fully agree, needs some discussion and improvement. Should government repositories of data become more useer friendly or should they remain just as repository of data?

On thursday evening, Geocat had a double session between speeches very focused on metadata and the importance of governmment spatial portals. We first focused mostly on GeoNetwork and Bridge, talking also about our future GeoCat Live. and, just before ending  the day, a workshop of 30 minutes to present GeoNetwork, which has followed by the first national meeting of geoinquietos.

It is hard to summarize in only one article all the huge dimension reached on this conference. A lot of optimism, willing to keep working and, most of all, the certainty that we are on the right path, helping free software and free data, focusing on the social part of our work. On Friday, almost to finish, Javier Sánchez oriened the end of the conference to this theme, talking about social companies, who have not only an economic result but also a social one.

In the end the Jornadas SIG Libre Girona are undoubtely the GIS Event (capital letters) to which every spanish speaker should take into account to be in contact with latest GIS news.

Original article here.

¿Qué es GeoNetwork?

October 28, 2012 under Java, SIG, Tecnologías

GeoNetwork is a web application that allows you to maintain a geographic referenced metadata catalogue. This means, a search portal that allows you to view metadata combined with maps. It strictly follows different standards for metadata, from Inspire to OGC. This has allowed GeoNetwork to expand to a lot of organizations, like the swiss geoportal or the brasilian one, not forgetting the New zealander.

It is deployed inside a java application container (like tomcat or jetty), working over the Jeeves framework. Jeeves is based on XSTL transformations that allows a simple quick development (and powerfull) of interfaces, for humans or machines (XML). This makes metadata from GeoNetwork to be easily accesible by different platforms.

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Apuntes del taller de GeoServer

March 2, 2012 under SIG

These are the notes I took on the GeoServer workshop at the last gvSIG Conference.
More information.

It is important to change the settings of the geoserver_data_dir in the web.xml file to keep the data each time you restart the application container (like Tomcat). It is also good to check out the other settings as it contains interesting facts such as the type of projections to be used or the size of the cache. There are configurable data on the fly and data not configurable on the fly.

Let’s try adding some data sources to generate the layers. To add a shapefile, you have to copy the file in the same physical server machine. To include the shapefile in GeoServer, look for the option of adding a new shapefile datastore type. If you use the location “file: data /…” you use a relative uri to geoserver. You can also search using the “Browse” and use absolute paths.

Warning: Do not you give permission to any user on the configuration interface because they can see all the physical hard disk in this type of dialog.

It is best to use memory mapped buffers (unless you use Windows) if you have enough RAM, then you will avoid continuous access to physical disk. Also, it is best to reproject from native to declared projection. If the shapefile is very big, calculate the bounding box take some time. This does not happen in real databases where spatial indexes.

GeoServer allows you to insert watermarks in your data (for example to use OpenStreetMap).

When you use database connections, you should check the validate connection option, because you never know when the connection is going to crash.

GeoWebCache allows, on the latest version of GeoServer, to set up easily which layers will be cached.

You can use data which varies through time, for example for storms and hurricanes. On the database table, you will have a column for time. You can also use elevation data, but then you have to use it with Google Earth. The interesting thing is that, once you have the data, some hipothetical free visor can be used to support it…

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Apuntes del taller GvSIG 2.0

February 8, 2012 under Java, SIG

This are the notes that I took over gvSIG 2.0 on the latests Jornadas GvSIG.

Pre-requisites:

  • Java
  • Eclipse
  • Ant (should)
  • Maven (should)
  • gvSIG (this is recursive :))

The main advantage of gvSIG 2.0 is that you can create a new plugin without knowing how does gvSIG work or having to compile it. We already have a gvSIG installation that deploys the binaries to the workspace. But we don’t have to change the source code of gvSIG, unless something doesn’t work (bugs) or we have to add some new functionality to the core. Better if you don’t touch it,ask the gvSIG developers and they will take care.

  Click here to read more.. »
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Guía para compilar gvSIG 2.0

January 8, 2012 under SIG

I am proud to share with you the steps to compile gvSIG 2.0, which I discovered thanks to some fellows of gvSIG, whom I met thanks to the latests Jornadas GvSIG.

Although you can find a full guide on the official documentation, this simple steps will let you customize and compile your own gvSIG2.0 version withouth much trouble.

Click here to read more.. »

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La importancia de los datos libres

April 21, 2011 under Libertad

I’ve been thinking for a while about writing about the importance of opendata, but is with the advertising given to Google Map Maker when I really understood the urgency of the matter.

Can you imagine a country with so poor geographic data that even the government doesn’t known which cities and towns do they have? How could they invest on roads, literacy, drinking water or even know that there are people who live there? How could they collect taxes or… count votes in elections!? Can you imagine that a battalion of soldiers use maps that are wrong and establish a base in the nearest country? An absurdity that happened recently on the border between Nicaragua and Costa Rica , which almost causes an international conflict.

If institutions publish their data and leave it to free access, anyone can verify the accuracy of the data and may suggest changes or corrections. But while this data remains locked away in dusty archives, the same mistakes will be made over and over again. We are not talking about sensitive data or national security, we discuss data that anyone who is physically present at the location can check whether it is correct.

But it is important not only that the data is freely available. It is also important to be free in their use. I gain nothing by looking at a map on page X of the Public Service if I can not use the data I am seeing. Seeing the traffic before you leave home can help you, but if my GPS can not use that information to guide me through the best path, it is useless.

Well, someone may say, if the source of the data (for example, the government) provide all services we will be needing, we don’t need a free use of the data. It is not enough. Why? Because opendata may have myriad of uses. It is a newly opened market to explore.

But, how does it benefit the private map provider? Are we suggesting to have data servers and offer free data without charging for its use? Is it the culture of all free? Of course not, nobody in their right mind would ever ask for this. The private provider can get great benefits releasing their data (others than charging for services based on this data) :

The first benefit is straightforward: if you manage a large community, the cost of renovation and expansion of their data will be greatly reduced. Vendors like TomTom or Nokia begin to understand the importance of these updates from their own users. OpenStreetMap is another clear example and direct the power of users: a source of geographic data that can compete (and win) on Google Maps or Bing created entirely and only by a combination of free data supplied by its users.

The second advantage is perhaps more complex to understand because it is not so straightforward. Ignoring all the classic advantages of freedom, there is still one more: You can always charge for commercial or intensively use. Although it does not benefit you at the beginning, if your data is good enough, sooner or later someone will think of some utility .

Some hustlers will have, at this point, if this is not what Google Map Maker does. Do they not collect updates of their users, giving them maps for free and charging only for intensive or commercial? No. To begin with, data isn’t free. This means that if you collaborate with Google Map Maker and update their maps and tomorrow you want to use these data to set up a commercial service, you couldn’t do it without going through a convoluted series of licenses. However, if instead of working with Google Map Maker, you contributed with a free platform for geographic data, you will be able to use this data on your service without problems.

Does this mean that I think Google Map Maker is useless? Neither. Probably someone will find a good use. But whatever the intended use, you can always get at least the same functionality with OpenLayers , OpenStreetMap data and free PNOA and the Cadastre (recently released). So why use an exclusive platform when you can use a free platform much more powerful?

But Google is good, someone may say, it offers free, quality data. Sure, and no doubt. But never forget that Google, beyond any good intentions, remains a business. And finally, the top priority of a company is to generate business to survive. And if Google has to change its way, to get ride of free offerings that are inconsistent with their business, they will. In fact, they already do it .

Mapa sencillo en Java

July 16, 2010 under Java, SIG

Sometimes you don’t know where to start when you enter the world of GIS programming. Too many libraries, IDEs, but the truth is, everyone assumes you already have a base and everything become chaos.

For beginners I would recommend that you take a look at a fairly new project aimed at extending Swing (the default graphics java library) with geographical widgets. In this way, add a map to a Java desktop application would be a task as simple as adding a button or text field.

Of course, GIS applications have some complexity, a simple display like this is not enough. But it is a good starting point to get familiar with what a map is and what can a developer do.

We start with a Java project and add SwingX-WS to its dependencies. Then, the following code would show a window with a simple map:

es.emergya.gis.examples package;

import java.awt.BorderLayout;

SwingWS {public class

public static void main (String [] args) {
Form = new JFrame JFrame ("Map");

JXMapKit JXMapKit jXMapKit1 = new ();
jXMapKit1
. setDefaultProvider (org.jdesktop.swingx.JXMapKit.DefaultProviders.OpenStreetMaps);
jXMapKit1.setDataProviderCreditShown (true);
jXMapKit1.setName ("jXMapKit1") / / NOI18N
jXMapKit1.setAddressLocation (new GeoPosition (41.881944, 39.627778));

form.getContentPane (). add (jXMapKit1, BorderLayout.CENTER);

form.pack ();
form.setVisible (true);
}

}

The tiles of the maps drawn from OpenStreetMap , but is fully configurable for any WMS server.

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