OSGeo Planet

From GIS to Remote Sensing: Semi-Automatic Classification Plugin v.5.0 "Kourou" Released: Supervised Classification Tutorial

OSGeo Planet - Sat, 2017-02-04 15:04
I am very glad to announce the availability of the new Semi-Automatic Classification Plugin (SCP) version 5.0, code name "Kourou" (dedicated to the Europe's Spaceport in French Guiana where Sentinel satellites are launched, see http://www.esa.int/Our_Activities/Launchers/Europe_s_Spaceport/Overview_of_Europe_s_Spaceport).
I have also updated the user manual that is available here.




In case the plugin is still not available inside QGIS Plugin Manager, you can perform a manual installation, following this guide.
Following the first basic tutorial of this new version.
Categories: OSGeo Planet

Free and Open Source GIS Ramblings: Gradient arrows

OSGeo Planet - Fri, 2017-02-03 20:03

Today’s post was motivated by a question following up on my recent post “Details of good flow maps“: How to create arrows with gradients from transparent to opaque?

gradient_arrow

The key idea is to use a gradient fill to color the arrows:

gradient_arrow_settings

It all seems perfectly straightforward: determine the direction of the line and set the gradient rotation according to the line direction.

But wait! That doesn’t work!

The issue is that all default angle functions available in expressions return clockwise angles but the gradient rotation has to be set in counter-clockwise angles. So we need this expression:

360-angle_at_vertex($geometry,1)

Happy QGISing!


Categories: OSGeo Planet

gvSIG Team: Geopaparazzi 5.2.0 is out! Compatibility with gvSIG Online

OSGeo Planet - Thu, 2017-02-02 18:43

zoom_geopaparazzi

The new versión of Geopaparazzi is out and probably the most important feature is the compatibility with gvSIG online. Great news for gvSIG Suite.

It is now possible to import and export geopaparazzi projects and spatialite databases from and to gvSIG Online. This enables the gvSIG Stack for proper digital field mapping with synchronization of data from and to the device.
Do you want to know more?

Read here…


Filed under: english, Geopaparazzi, geoportal, gvSIG Online, SDI Tagged: gvSIG Suite
Categories: OSGeo Planet

Andrea Antonello: Geopaparazzi 5.2.0 is out!

OSGeo Planet - Thu, 2017-02-02 17:11
We just released geopaparazzi 5.2.0 to google play.

The release comes with a whole pile of bugfixes (see here), but also some nifty new features. Let's have a look at the most important ones.

Geopaparazzi & gvSIG OnlineProbably the most important feature is the compatibility with gvSIG online. This is an ongoing effort within the gvSIG Association. HydroloGIS and Scolab are currently working on the integration.

It is now possible to import and export geopaparazzi projects and spatialite databases from and to gvSIG Online. This enables the gvSIG Stack for proper digital field mapping with synchronization of data from and to the device.

Cesar from Scolab also added a nice feature that also people without the need of a serverside will appreciate: the possibility to add pictures to spatialite geometries. This has always been possible for notes in a geopaparazzi project, but now it is possible also for general spatialite layers.

Once you select a feature and enter the attributes editing tool, you will now have a new camera icon:

Tapping on it will open the images thumbnail view:

The images are saved in the database into a table allocated once this functionality is triggered for the first time.


Zooming the map viewSome users asked for a zoom-in-the-zoom functionality. This is due to the high resolution of the new devices' screens. The idea is to have a secondary zoom (let's call it scaling) that works in parallel to the geographic zooming.

So for each geographic zoomlevel the user is now able to scale the current image to make it more readable.

Look at the following comparison to better understand:


This feature addition has two main drawbacks:
  • we had to change the position icon with a vector image so that it would not get blurry too early (it was ugly already at first scaling). Well, that is probably no drawback...
  • the automatic center on gps will not work properly, since the bounds of the screen are affected by the scaling and the centering (for example while driving) will take place far outside the device's screen. For now I can live with that, I hope you also can.

And how do you scale up and down? Just long tap on the zoom button. The setting is kept until one exits the application through the exit button.

Load data foldersIt is now possible to load folders of tilesources and folders of spatialite databases.

In the add-sources views in the lower left corner a sparkling new add folder icon is present:






Since this loads a lot of data, in the case of spatialite databases, all the tables are now added as not visible by default. The user will then enable the ones he would like to see.

Gps StatusGps Status will no longer be the gps status app. It is not open source and it doesn't work any more with intent calling, so for now we will have the Gps test app to help out with gps status visualization. It is free and open source and definitely fits better in our family.




Other stuffApart of this, fixes have been done to the WMS 1.3 support, which wasn't properly working, a major languages update has been done and the we are updated to properly work with the latest Android 7 version.

Enjoy!!






Categories: OSGeo Planet

gvSIG Team: Aprendiendo SIG con Juego de Tronos (IV): Herramientas de selección

OSGeo Planet - Wed, 2017-02-01 05:49

En todo SIG son muy importantes las herramientas de selección, entre otras cosas porque hay muchas herramientas que se ejecutan sobre los elementos seleccionados. Además pueden servirnos para localizar fácilmente elementos con determinadas características. 

Antes de empezar conviene recordar, como vimos en el post de Tablas, que cuando seleccionamos elementos de una capa también se seleccionan en su tabla de atributos (y viceversa).

Las herramientas de selección se pueden encontrar en el menú “Selección” o en su correspondiente barra de botones:

015_got

El mayor número de herramientas de selección son gráficas y su funcionamiento es similar (y muy sencillo). Vamos a explicar este funcionamiento y os animamos a que vayáis probando las distintas herramientas de selección gráfica.

Para aplicar la mayoría de las herramientas de selección gráfica se debe hacer clic con el botón primario del ratón sobre el punto de inicio de la selección, arrastrar y soltar para finalizar la selección. En el caso de la selección por polígono, por ejemplo, se hace clic en cada vértice del polígono y doble clic para finalizar la selección. Y en el caso de la selección simple sólo se necesita hacer un clic sobre el elemento a seleccionar.

Para agregar entidades a una selección existente, se debe mantener presionada la tecla “Control” mientras se seleccionan entidades. Para quitar una o más entidades de una selección de varias entidades, se debe mantener presionada la tecla “Control” y hacer clic en ellas. Los elementos seleccionados se muestran de color amarillo.

¿Lo habéis probado ya?

Bien, pues vamos a ver con mayor detalle las herramientas de selección no gráfica. Antes de empezar abrir vuestro proyecto de “Juego de Tronos”…

Selección por atributos

Esta herramienta se encuentra en el menú “Selección/Selección por atributos” o en su botón correspondiente:

016_gotPermite seleccionar entidades mediante una consulta de atributos.

La interfaz es la siguiente:

017_got

  1. Campos. Listado de campos de atributos de la capa. Al hacer doble clic en un campo lo incorpora a la consulta de selección.
  2. Operadores lógicos. Permite insertar, pulsando sobre ellos, una expresión lógica a la consulta.
  3. Valores conocidos. Muestra una lista con los distintos valores que toma el campo seleccionado. Al hacer doble clic sobre un valor lo incorpora a la consulta.
  4. Consulta. Espacio donde se va representando la consulta a ejecutar. Permite escribirla directamente.
  5. Opciones de selección.
    • Nuevo conjunto. Crea una selección nueva.
    • Añadir al conjunto. Añade a la selección ya existente el resultado de la nueva consulta.
    • Seleccionar del conjunto. Crea una selección de lo seleccionado. Realiza la consulta sobre los elementos previamente seleccionados y no sobre toda la capa.

Ahora vamos a aplicar la herramienta de “Selección por atributo” para seleccionar todos los castillos de nuestra cartografía. Para ello ponemos activa la capa “Locations” (hacemos clic sobre ella y su nombre se pondrá en negrita). Lanzamos la herramienta de “Selección por atributo” y realizamos la siguiente consulta: “type” = ‘Castle’

017b_gotAl pulsar el botón de “Nuevo conjunto” nos seleccionará todos los castillos de la capa. Ahora ya podemos consultar la tabla de atributos de la capa para comprobarlo (como vimos en el post “Tablas”) o navegar por la Vista para ver la ubicación de estos castillos (como vimos en el post “Herramientas de navegación”).

Selección por capa

Esta herramienta está disponible desde el menú “Selección/Selección por capa” y en su botón correspondiente:

018_got

Permite seleccionar elementos de una capa en función de su relación espacial con elementos de otra capa.

La interfaz es la siguiente:

019_got

  1. Seleccionar de las capas activas los elementos q…Desplegable que permite indicar el método de selección.020_got
  2. Elementos seleccionados de la capa. Permite seleccionar mediante un desplegable la capa con la que se va a hacer la relación espacial. Essa capa debe tener seleccionados los elementos que queramos se tengan en cuenta. Si queremos que la relación espacial sea sobre toda la capa…deberemos tener seleccionados todos los elementos de esa capa.
  3. Opciones de selección. Similares a las de “Selección por atributos”.

Vamos a hacer un ejercicio consistente en seleccionar todos los elementos de la capa de localizaciones (“Locations”) ubicados en el reino de las Tierras del Oeste (“The Westerlands”). Para ello activamos la capa “Political” que cotiene los distintos reinos de Juego de Tronos y utilizando la herramienta de “Selección por atributos” realizamos la siguiente consulta: name = ‘The Westerlands’

También podríamos haber seleccionado el polígono gráficamente, pero así repasamos la herramienta que acabamos de conocer. El resultado será:

021_gotYa tenemos el elemento seleccionado de nuestra capa de referencia. Ahora activamos la capa “Locations” y pulsamos la herramienta de “Selección por capa”. En la ventana que nos abre indicamos lo siguiente:

022_gotPulsamos el botón “Nuevo conjunto” y como resultado nos seleccionará todas las localizaciones contenidas en “The Westerlands”:

023_got

Hasta el próximo post…


Filed under: gvSIG Desktop, spanish, training Tagged: selección por atributos, selección por capa
Categories: OSGeo Planet

gvSIG Team: Learning GIS with Game of Thrones (III): Navigation tools

OSGeo Planet - Tue, 2017-01-31 15:03

When we speak about navigation tools we are referring to all of those that allow us to go over the cartography, and here we can find from the typical zooms to zoom in and zoom out (that means, to change the visualization scale) to other tools more elaborated.

At this post we are going to see these tools, explaining the less known ones better, that are very useful.

Navigation tools are grouped at the View menu, Navigation sub-menu, being also available as buttons.

008_got009_got

We are not going to explain basic tools working in detail because they are very intuitive and its use is similar to other applications. In order of appearance at the toolbar we have the basic navigation tools: Pan, zoom in and zoom out buttons, zoom to the whole extension of the cartography, return to a previous zoom, zoom to selected elements, and three advanced tools or not as much used ones: frame manager, centre view to coordinates or locator by attribute. Learning to use the basic tools is very easy, we only press them and interact with the view, so we are going to explain the other tools directly.

Before starting, we are going to open the previous project saved at the last post.  An

Firstly we are going to add two new layers (review the first post in case you have any doubt): “Wall” and “Locations”.

010_got

We have the wall and important locations already (cities, castles…) in our project.

If we press on the “Wall” layer with secondary button of the mouse ans we select “Zoom to layer” the zoom will change to the maximum extension of the wall.

011_got

If you have noticed it, “Locations” layer has changed its symbology at that level of zoom; we will see how to create that type of changing symbology in future posts.

Now we are going to use “Locate by attribute” tool, that you can find at the “View/Navigation/Locator by attribute” menu or its corresponding button.

012_got

This tool allows to centre the View to the elements of a layer that have a specific attribute. In our case we are going to use it to visit some outstanding locations of Game of Thrones. Selecting this tool, a new window will be opened where we can select the layer, field and value that we want to locate in different pull-down menus.

e012b_got

We can locate, for example, “Winterfell”.

Another tool that is not as much known but it’s very useful is the “Frame manager”, that allow us to save a zoom of a specific area of the View. It allows us to return to that zoom in any moment.

This tool is available from the “View/Navigation/Frame manager“ menu or from its corresponding button.

013_got

A new window will be opened where we can name the frame that we want and save it. It will save it at the favourite frame list. As we are in “Winterfell”, we are going to save that frame. We repeat the “Zoom to layer” action on the “Wall” layer and we save a new frame. You can save as many frames as you want. If you have folloewd the steps correctly you will have something like that:

e014_got

Now, every time that you want to go to any of these frames you only have to open the “Frame manager” to open that window, and select the frame that you want.

With this tool we finish this quick viewing to the navigation tools. Now you can move on your Game of Thrones map and explore it.

Don’t forget to save your project. See you at the next post…


Filed under: english, gvSIG Desktop, training Tagged: Game of Thrones, Locator by attribute, Navigation, Zoom manager
Categories: OSGeo Planet

GeoSolutions: GeoServer Code Sprint 2017

OSGeo Planet - Tue, 2017-01-31 14:15

GeoServer

We have offered to host the GeoServer team for a Java 2017 code sprint to look at updating, fixing and documenting the the GeoServer REST API. The GeoServer REST API is used to remotely manage a GeoServer instance and has proven highly successful for automation, integration with other applications, with libraries for java and python remote management.

rest-api

The code sprint is dedicated to:

  • Migrating from the restlet library to Spring MVC library. As an early adopter GeoServer selected the restlet library as best of breed at the time. It has not aged well, and Spring MVC represents a supported annotation based solution that is familiar to more developers.
  • Although popular the REST API has not attracted a lot of investment, leading it to have the highest bug count of any of our GeoServer modules! This sprint would like to directly reduce this bug count, and indirectly reduce this bug count by introducing more developers to this area of the codebase.
  • The REST API also has the greatest number of requests for documentation and examples. This code sprint will update the documentation for each area of the REST API as as it is migrated, and look at some of the solutions for the automated collection of examples requests.
  • We will be sure to test against the gsconfig python library and geoserver-manager java library.

The GeoServer team has previously planned and executed a highly successful code sprint. We would like to once again ask for your support and participation in 2017.

Viareggio, Lucca

The code sprint is planned for a week in March in the GeoSolutions headquarters of Viareggio, Lucca. Thanks to GeoSolutions for providing a venue, space is limited to 10-15 people so hit the wiki to sign up if you are interested.

Viareggio,_passeggiata_a_mare_2

A note on the timing: We were unable to join the Daytona Code Sprint 2017 as it is scheduled too close to the GeoServer 2.11 code freeze. GeoSolutions offer to host in Europe will reduce travel costs allowing us to run the event with minimal sponsorship.

Participation and Sponsorship

We have the following sponsorship levels available:

  • Gold: $1000
  • Silver: $500
  • Bronze: $250

We are reaching out to international and local sponsors. Contributions will be put towards travel costs for overseas sprinters who would be otherwise unable to attend. Any surplus at the end of the event will be turned over to OSGeo or used for a future code sprints.

For more details on participation, sponsorship or budget for the event please see the Java 2017 Code Sprint 2017 on the OSGeo wiki.

Categories: OSGeo Planet

Jackie Ng: A few days layer ...

OSGeo Planet - Tue, 2017-01-31 12:11
Not only does AppVeyor gives us continuous integration, it can give us continuous delivery as well.

So after getting the newly migrated MapGuide Maestro on GitHub hooked up to AppVeyor for CI and automated publishing of code coverage results to Coveralls, I wanted to look at how AppVeyor can be used for automating the creation of GitHub releases. The ideal scenario, is that when I decide to put out a release, I hit some button or run some command and a new GitHub release will show up a few minutes later.

It turns out, AppVeyor has a whole section on their documentation dedicated to this very subject! Some tweaks were required to the AppVeyor build system so that it also builds the API/User documentation and zip/installer packages and then by specifying these artifacts in the artifacts section of appveyor.yml, they will appear in the artifacts section of the AppVeyor build page.

What that means is that you now have access to the latest builds of MapGuide Maestro straight after AppVeyor builds and validates them. However, this is not the way I want you to access official releases of Maestro, I still want GitHub releases created for this particular case, and ideally in an automated fashion.

This is where we set up our AppVeyor configuration to deploy using the GitHub deployment provider, with the trigger being a push of a git tag. What this means in practice is when I decide to put out an official release, I make the release tag in Git, push it out to GitHub. This triggers AppVeyor to do its usual CI and artifact packaging. But because this is a release tag, it will also automatically create a corresponding GitHub release in a draft state and uploads the associated artifacts of this build with it.

From there, I can visit the draft release page and tidy up the release description and add release notes, click the publish button and voila! A new release is ready for you to download. How well is this automated process? Check out this test release and find out for yourself.

I'm really liking this well-oiled CI/CD machine, further solidifying my justification for making the move to GitHub in the first place. Oh, and as the above screenshot shows, I also got my first pull request today for Maestro too. Things are looking up!
Categories: OSGeo Planet

PostGIS Development: PostGIS 2.3.2 Released

OSGeo Planet - Tue, 2017-01-31 00:00

The PostGIS development team is pleased to announce the release of PostGIS 2.3.2 As befits a patch release, the focus is on bugs and breakages. Best served with PostgreSQL 9.6.1+ and pgRouting 2.3.2.

Continue Reading by clicking title hyperlink ..
Categories: OSGeo Planet

Paulo van Breugel: Terrain attribute selection in environmental studies

OSGeo Planet - Mon, 2017-01-30 11:18
Terrain attribute selection Exploring species-environment relationships is important for amongst others habitat mapping, biogeographical classification, conservation, and management. And it has become easier with (i) the advance of a wide range of tools, including many open source tools, and (ii) availability of more relevant data sources. For example, there are many tools with which it … Continue reading Terrain attribute selection in environmental studies
Categories: OSGeo Planet

Fernando Quadro: Curso de GeoServer

OSGeo Planet - Mon, 2017-01-30 10:30

Caros leitores,

Quero convidá-los a participarem do Curso Online de GeoServer que estarei ministrando pela GEOCURSOS. O objetivo do curso é que você aprenda a disponibilizar, compartilhar e editar dados geográficos na internet com o GeoServer.

No curso serão abordados tópicos como: configuração de dados, criação de estilo com SLD, padrões OGC, interface administrativa (web), visualização cartográfica com OpenLayers, entre outros.

O curso ocorrerá entre os dias 25 de abril e 04 de maio (terças, quartas e quintas) das 20:00 as 22:00 (horário de Brasília).

Aqueles que poderem divulgar para seus contatos, agradeço. Quem quiser saber mais informações sobre o curso, pode obtê-las no site do curso (http://www.geocursos.com.br/geoserver), twitter (http://twitter.com/geo_cursos) e pelo facebook (http://www.facebook.com/geocursosbr).

Posts RelacionadosSovrn
Categories: OSGeo Planet

gvSIG Team: Aprendiendo SIG con Juego de Tronos (III): Herramientas de navegación

OSGeo Planet - Mon, 2017-01-30 05:32

Cuando hablamos de herramientas de navegación nos referimos a aquellas que nos van a permitir recorrer la cartografía y aquí entran desde los típicos zooms para acercar y alejar la imagen (es decir, para cambiar su escala de visualización) a otras herramientas más elaboradas.

En el post de hoy veremos estas herramientas, deteniéndonos en aquellas menos conocidas y, sin embargo, muy útiles.

Las herramientas de navegación se agrupan en el menú Vista, submenú Navegación, estando también disponibles como botones.

008_got009_got

No vamos a entrar en detalle en el funcionamiento de las herramientas básicas porque son muy intuitivas y su uso es similar al de otras aplicaciones gráficas. Por orden de aparición en la barra de botones tenemos las herramientas básicas de navegación: desplazamiento, botones para acercar y alejar el área de visualización, zoom a la extensión máxima que ocupa la cartografía, volver a un encuadre anterior, mostrar la extensión máxima de los elementos seleccionados, y tres herramientas más avanzadas o de uso menos común: gestor de encuadres, centrar la Vista sobre un punto y localizador por atributo. Aprender a manejar las herramientas básicas es tan sencillo como pulsar cada una de ellas e interactuar con la Vista, por lo que no vamos a ir directamente al resto de herramientas comentadas.

Antes de empezar, abrir el último proyecto guardado como resultado del ejercicio del post anterior.

Lo primero que haremos es añadir dos nuevas capas (revisa el primer post si tienes dudas): “Wall” y “Locations”.

010_got

Ya tenemos el muro y localizaciones importantes (ciudades, castillos,…) en nuestro proyecto.

Si pulsamos con el botón secundario del ratón sobre la capa “Wall” y seleccionamos “Zoom a la capa” nos llevará a la extensión máxima que ocupa el muro.

011_got

Si os habéis fijado, la capa “Locations” ha cambiado su simbología a este nivel de zoom; en futuros post veremos la forma de hacer este tipo de leyendas cambiantes.

Ahora vamos a utilizar la herramienta de “Localizador por atributo”, que podéis encontrar en el menú “Vista/Navegación/Localizador por atributo” o en su botón correspondiente.

012_got

Esta herramienta permite centrar la Vista en el elemento o elementos de una capa que tengan un determinado atributo. En nuestro caso vamos a utilizarlo para visitar algunas localizaciones destacadas de Juego de Tronos. Al seleccionar esta herramienta se nos abrirá una nueva ventana en la que podemos seleccionar mediante desplegables la capa, el campo y el valor que queremos localizar.

012b_got

Podemos localizar, por ejemplo “Winterfell” (Invernalia).

Otra herramienta de navegación poco conocida y muy útil es el “Gestor de encuadres”, que permite guardar un encuadre a una determinada zona de la Vista con el fin de volver a él en cualquier momento.

Esta herramientas está disponible desde el menú “Vista/Navegación/Gestor de encuadres“ y en su botón correspondiente.

013_got

Nos abrirá una nueva ventana, en la que podemos dar un nombre al encuadre que queramos guardar y pulsando “Guardar” lo añadirá a la lista de encuadres favoritos. Como estamos en “Winterfell”, vamos a guardar este encuadre. Ahora repetimos la acción de “Zoom a la capa” con la capa de “Wall” y guardamos un nuevo encuadre. Podéis guardar tantos encuadres como queráis. Si habéis seguido correctamente los pasos tendréis algo así:

014_got

Ahora cada vez que queráis ir a uno de estos encuadres no tenéis más que pulsar el botón de “Gestor de encuadres” para que aparezca esta ventana. Seleccionar del listado el encuadre al que queréis navegar y pulsar el botón “Seleccionar”.

Con esta herramienta acabamos este vistazo rápido a las herramientas de navegación. Ya podéis recorrer y explorar vuestro mapa de Juego de Tronos.

No os olvidéis de guardar vuestro proyecto. Nos vemos en el siguiente post…


Filed under: gvSIG Desktop, spanish, training Tagged: gestor de encuadres, Juego de tronos, localizador por atributo, navegación
Categories: OSGeo Planet

PostGIS Development: PostGIS 2.2.5 Released

OSGeo Planet - Mon, 2017-01-30 00:00

The PostGIS development team is pleased to announce the release of PostGIS 2.2.5 As befits a patch release, the focus is on bugs and breakages.

Continue Reading by clicking title hyperlink ..
Categories: OSGeo Planet

Bjorn Sandvik: Mapping a real time snow cover

OSGeo Planet - Sat, 2017-01-28 16:33
Norway is a country with huge climate variations between seasons, lowlands and mountains, coastal areas and inland, and between north and south. In the recent years, we have also seen more extreme weather and greater fluctuations in temperature and snow cover. At the same moment of time there might be meters of snow in the mountains, while the trees are blooming by the fjord a few kilometers away. Outdoor activities are popular among citizens and tourists alike, and in Norway you can do typical summer and winter activities all year around. The goal of this blog post is to create a near real time map of the snow cover, where the snow blends into the landscape.

The snow map of Jountunheimen we're going to create.
As shown on this blog, I like to create maps and 3D visualisations using a wide range of open source tools, combined with various programming techniques. This snow mapping experiment is no exception. Open Source allows me to mix and match the tools and techniques I need, and doing this programmatically has the added benefit of automation. When the full map making process is defined, we can easily run it for various areas and terrains. It was an important goal of this project to keep the snow cover up­-to-­date on a daily basis.

Cross­country skiing in Jotunheimen national park. Photo: Bjørn SandvikGeospatial datasets can be very large, and we often have to divide the data into chunks to be able to run calculations. I have divided mainland Norway into 218 cells, each covering an area of 50 x 50 km. With datasets at 10 meters resolution, all tools presented below were capable of processing the data.

The Norwegian Mapping Authority released its topographic datasets in 2013. This included an elevation model of mainland Norway at 10 m resolution. The Norwegian Water Resources and Energy Directorate (NVE) is monitoring the country's water resources, and they provide data of snow gain, snow melt and snow depth. As my map is aimed towards cross­-country skiers, I’m using a dataset showing areas with a skiing surface, based on interpolated weather observations.

Elevation data
The 10 m digital elevation model (DEM) from the Norwegian Mapping Authority was used to blend the snow into the landscape. A few GDAL commands allowed me to create a 50 x 50 km DEM from the nation­wide DEM, and to translate it into the various formats supported by the tools in use.

The 10 m elevation model contains too much detail to represent a snow cover. I could downsample the dataset, but that would blur out important terrain features like mountain ridges and valley edges. Terrain Sculptor came to the rescue. It is a tool by Bernhard Jenny and Anna Leonowicz to generalize terrain models for relief shading. It removes unnecessary and distracting terrain details, and better resembles a smooth snow covered landscape. Unfortunately, Terrain Sculptor can only be used with a graphical interface, and not as a command line tool, so it can not be used in an automatic process. I used it to create a generalised terrain model for the 50 x 50 km area of Jotunheimen and Tyin.

The generalised elevation model was used to create a shaded relief. We can easily create a grayscale hillshade with GDAL, but the snow required some tints to look better. I created a continuous colour scale from blue shadows to white with a touch of yellow, and turned the grayscale hillshade into a tinted hillshade. For areas without snow, I used the same elevation data to create a color relief progressing from green for lower elevations up through yellows/browns, and on to grays and white at the highest elevations.

Finally, the elevation model was used to calculate steep terrain (slope) where there will be less snow. The steep terrain will be subtracted from the snow surface to improve the view in alpine areas. This was achieved in a series of steps: A slope surface was calculated from the DEM, and then areas steeper than 50 degrees were extracted and vectorised. The process of vectorising raster data is described below.

Snow cover
The skiing surface dataset from the Norwegian Water Resources and Energy Directorate (NVE) is available from a public Web Map Service (WMS) with a 1 km resolution. The dataset is updated 8 times a day. The original WMS image includes 4 colours: Blue represents skiing surface with dry snow, violet is surface with wet snow, yellow is areas with little snow, and green is areas without snow. As the map is targeted towards cross country skiers, the dry (blue) and wet (violet) snow are combined into one layer. The areas with little snow (yellow) are not included in this map, but could be used to create a more gradual shift between snow cover and bare ground.

The original WMS image of skiing conditons.
Wet at dry skiing conditions combined. Each square is 1 x 1 km. 
To avoid the pixelated appearance of the snow surface, the image is vectorised into smooth scalable snow polygons. This was achieved using Potrace by Peter Selinger, an open source tool for tracing bitmaps. Potrace transforms the the blocky WMS image into smooth vectors. It supports GeoJSON output, which makes it easier to use in geographic applications. A problem with this technique is that the smooth polygons seem more accurate than they are. There are other, and probably better, ways to interpolate the data, as following height contours in the area.

Vectorised image from Potrace.
With all the map layers in place, Mapnik was used to generate the map shown below. Mapnik is an open source toolkit to generate beautiful maps from different vector and raster sources. The order and styles are expressed in an XML document, and then applied to the data. First, colour relief, lakes, snow polygons, steep terrain, glacier polygons and road lines are added in turn. Then all the layers are blended with the hillshade, before adding buildings and a thin lake outline as a final touch.

Jotunheimen and Tyin covered with a snow cover obtained from the Norwegian Water Resources and Energy Directorate on. The map image is applied to a 3D model using elevation data from the Norwegian Mapping Authority.

Categories: OSGeo Planet

OSGeo News: GeoPython 2017

OSGeo Planet - Fri, 2017-01-27 18:41
Categories: OSGeo Planet

From GIS to Remote Sensing: SCP Questions of This Month: January

OSGeo Planet - Fri, 2017-01-27 11:09
This post is a collection of questions and answers about the Semi-Automatic Classification Plugin (SCP) and remote sensing which were discussed in the Facebook group and the Google+ Community this month.
These questions vary from supervised classification technique to software issues, and can be useful to the readers of this blog for solving issues about the use of SCP.

Categories: OSGeo Planet

gvSIG Team: Learning GIS with Game of Thrones (II): Attribute table

OSGeo Planet - Fri, 2017-01-27 11:03

We follow with this mini-course about the introduction to Geographic Information Systems with Game of Thrones.Today we are going to see how to open the attribute table of a layer.

Firstly we are going to open our project, that we saved when finishing the first exercise. Then we are going to add a new layer (such as we saw in that first exercise), called “Political”, that has the different kingdoms of the “Westeros” continent, known as “Seven kingdoms” too. The new layer has a legend that shows it without fill and with a border line in black colour and thicker.

To see the alphanumeric information that is contained in this layer we press the name of the layer with the secondary button at the Table of Contents. A menu will be opened where we have to select the “Attribute table” option.

005c_got

The attribute table shows us the information about the political division of the continent, with the name of the different territories and their governing houses:

e005b_got

The regions are Dorne, Stormlands, The Reach, Crownsland, The Westerlands, The Vale and Riverlands. They are completed with: The Iron Islands, The North, New Gift and Bran’s Gift and the area beyond the wall, called Wildlings. In another post we will see how to edit this table and add more information.

Something important that we have to know is that the attribute table and the layer with graphical elements are two different ways to see the same information. Each row of the table is a different geometry (line, point or polygon depending on the layer). A very graphical way to see it is selecting an element in the attribute table; for that we have to press the row that we want to select. The corresponding geometry will be selected automatically.

For example if I select the row of The North region, I will get this graphical selection:

e006_got

You can select the different rows of the Table and see its correspondence in the cartography. And if you want to remove any selection you have to use the “Clear” option of the “Selection” menu or its corresponding button:

007_gotIt’s easy, isn’t it? Don’t forget to save your project and we will continue learning at the next post…


Filed under: english, gvSIG Desktop, training Tagged: Alphanumeric information, Attribute table, Game of Thrones, Introduction to GIS, Table
Categories: OSGeo Planet

Jackie Ng: A few hours later ...

OSGeo Planet - Thu, 2017-01-26 15:32
Moving MapGuide Maestro to GitHub has already paid off!

The code is hooked up to AppVeyor for automatic continuous integration

Our unit test suites are hooked up to OpenCover, whose reports AppVeyor will automatically upload to coveralls.io.

And these services are all free!

And we get some nice badges to show for it!

So just to give some context for that coverage result: This coverage is for the MaestroAPI part of Maestro. It does not cover the WinForms application itself, which I find trying to write automated end-to-end tests (and hence coverage) to be a fruitless endeavor. It will either work or not, that's as good enough of a test as any. MaestroAPI on the other hand, is the engine that drives the application and this is something that definitely needs the test validation and coverage as it has uses outside of the Maestro application and we need objective confidence in the stability and robustness of the MaestroAPI, which these aforementioned services will give us.
Categories: OSGeo Planet

gvSIG Team: Talking about SDI for IUCN with gvSIG Online

OSGeo Planet - Thu, 2017-01-26 10:33

Here you have a video about SDI project for IUCN (International Union for Conservation of Nature) with gvSIG Online. Spatial Data Infrastructure with Open Source.


Filed under: english, geoportal, gvSIG Online, Projects, SDI Tagged: IUCN
Categories: OSGeo Planet

Jackie Ng: Announcing: MapGuide Maestro is moving to GitHub

OSGeo Planet - Thu, 2017-01-26 10:15
After some thoughts and considerations, I've decided to move MapGuide Maestro out of the MapGuide Open Source SVN repo and out into its own GitHub repository.

The primary motivation was performance (git is way faster than svn and enables more productive development) and secondly, the "pull request" model of GitHub and other DVCSes is more conductive to external contributions than what we currently have now, which is code sitting as a sub-project in a SVN repository that requires special vetting and access for commit access to be granted.

Whereas with GitHub and friends it's just fork the repository, make your changes and send back a pull request. At no point in the above process do I ever have to get involved beyond reviewing and accepting any pull requests that comes my way. Less administrative burden on my end, less bureaucratic road blocks for external contributions on yours. Win win for everyone!

As of this post, I will cease to make any more Maestro-related commits to the SVN repo, I'll be migrating all Maestro-related issues and wiki content over to GitHub. Do not make anymore Maestro-related issues/tickets on the MapGuide Trac instance, make them on the GitHub project instead. Once the migration of issues and wiki content has completed, I'll remove Maestro from the SVN repo. Old releases will stay on the OSGeo download server, but new ones will be on GitHub.
Categories: OSGeo Planet
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