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).

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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

gvSIG Team: Learning GIS with Game of Thrones (I): Adding data to a project

OSGeo Planet - Thu, 2017-01-26 09:53

This series of posts will try to show how to learn to use a GIS without previous knowledge and through several practical exercises. To make learning entertaining we are going to use a series of layers related to Game of Thrones fiction world. And we will use gvSIG Desktop as software, an open source GIS used in more than 160 countries. They will be very easy posts where we will delve into the basic tools of a Geographic Information System little by little. We are going to start with something basic, adding files with cartographic data.

You can download installable version as well as portable one for the different operating systems from the gvSIG Association website. If you have any problem with the installation or using the software you can use the users mailing list to comment it with the community and for supporting.

Data to be used in this series of posts can be downloaded from here.

Firstly we will open our gvSIG. We will see the interface with these components:

e001_got

  1. Menu bar.
  2. Buttons bar
  3. Project manager. It allows to manage all the documents which make a project.
  4. Work area. In this space we will be able to have the different project documents
    opened and work with them.
  5. Status bar. The status bar provides information about coordinates, distances, etc.
    to the user.

The document that we are interested in is the document called “View”. It allows to work with cartographic data. In a View, the geographic information is represented as a dataset.

As the “View” document is selected by default (it’s highlighted) we only have to press “New” button and a new View will appear. We will maximize the window.

Now we are going to add layers in our View. For that we only have to press the “Add layer” button, that we can find at the “View” menu, or at this button:

002_got…a window with several tabs is opened. They are the different cartographic information sources that we can load (we will focus on the the first one, “File”).

e003_got

We are going to press “Add” button to load our first layer. For that we are going to search it in our data folder, selecting “Land.shp” file. This file goes with another one called “Land.gvsleg” (you can check it in your browser), that includes a predefined legend. Therefore the layer will be loaded in green colour and without background (in another post we will see how to change a legend). It represents the known earth area in Game of Thrones. At the left side (called table of contents) of the View you will see the name of the layer and its legend.

Pressing on the name of the layer with the secondary button of the mouse, a contextual menu will appear, that includes the “Add to locator” option. We select it and we will be able to see that the same layer appears in the bottom left-hand box. The locator will show the visible area of the View in a red rectangle.

Now that we know how toadd layers we are going to add Islands, Landscape, Lakes, and Rivers layers. Dragging each layer at the table of contents we can change their order of visualization. With that we would have a physical map of Game of Thrones.

Finally we are going to change the background colour of the View from white colour to a light blue one, that will allow us to identify it as sea. At the “View” menu we will select the “Properties” option. In the new window we will se the option to change the background colour.

The final results will be similar to this one:

e004_got

Save your project and see you in the next exercise…


Filed under: english, gvSIG Desktop, training Tagged: add layer, background colour, Game of Thrones, Introduction to GIS, locator, tutorial
Categories: OSGeo Planet

Fernando Quadro: Curso de GIS para Android

OSGeo Planet - Wed, 2017-01-25 10:19

Neste curso de Android ministrado pela Geocursos você será apresentado a uma das plataformas mais populares entre os dispositivos móveis, dispositivos esses que estão revolucionando o mercado no uso para alternativas geotecnológicas, devido a quantidade de mecanismos embarcados (exemplos: GPS, Bluetooth, GPRS, etc).

Este curso online tem o objetivo de capacitar os participantes a desenvolverem aplicações SIG/GIS (Sistema de Informações Geográfica) com a plataforma Android, sendo voltado para estudantes e profissionais em busca de um maior conhecimento a respeito ou que possuam demandas na área de Geotecnologias. Para participar do curso é necessário possuir prévios conhecimentos acerca da linguagem Java.

Veja abaixo os tópicos abordados no curso:

1. Teoria sobre sistemas de informações geográficos
2. Configuração de ambiente usando Android SDK, entendendo ADT
3. Entendendo layouts para plataforma e construções de layouts usando Eclipse
4. Criação e configuração de base embarcada usando SQLite
5. Uso de provedores de mapas digitais (Google Maps, OpenStreetMap e outros)
6. Utilização de mecanismos embarcados (GPS, Bluetooth, GPRS e outros)
7. Introdução aos padrões de marcação de dados geográficos (GML, WFS e outros)
8. Criação de serviços Restful para sincronização de dados geográficos
9. Criação de uma aplicação JavaEE simples para utilização destes serviços

O curso inicia em março, e as inscrições já estão abertas. Verifique maiores informações em:

http://www.geocursos.com.br/android/

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gvSIG Team: Aprendiendo SIG con Juego de Tronos (II): Tablas de atributos

OSGeo Planet - Wed, 2017-01-25 05:42

Seguimos con este mini-curso de introducción a los Sistemas de Información Geográfica con Juego de Tronos. Hoy vamos a ver cómo abrir la tabla de atributos de una capa.

En primer lugar abrimos nuestro proyecto, que guardamos tras finalizar el primer ejercicio. A continuación vamos a añadir una nueva capa (tal y como vimos en ese primer ejercicio), denominada “Political” y que contiene los distintos reinos del continente de “Westeros”, también conocido por “Siete Reinos”. La nueva capa tiene una leyenda que la muestra sin relleno y con una línea de borde de color negro y más grueso.

Para ver la información alfanumérica que contiene esta capa pulsamos con el botón derecho sobre el nombre de la capa en la denominada Tabla de Contenidos. Se abrirá un menú en el que debemos seleccionar la opción “Tabla de atributos”.

005_got

La tabla de atributos nos muestra la información sobre la división política del continente, con el nombre de los distintos territorios y sus casas gobernantes:

005b_got

Las regiones son Dorne, Stormlands (Tierra de la Tormenta), The Reach (El Dominio), Crownsland (Tierra de la Corona), The Westerlands (Tierras del Oeste), The Vale (El Valle de Arryn) y Riverlands (Tierra de los Ríos). Completan los territorios del continente: The Iron Islands (Las Islas del Hierro), The North (El Norte), las zonas New Gift y Bran’s Gift de la Guardia de la Noche y el área de más allá del muro denominada Wildlings. En otro post veremos cómo editar esta tabla y añadirle más información.

Algo importante que debemos saber es que la tabla de atributos y la capa con elementos gráficos son dos formas de ver la misma información. Cada fila de la tabla se corresponde con una geometría (línea, punto o polígono según el caso de la capa). Una forma muy gráfica de ver esto es seleccionando un elemento en la Tabla de atributos; para ello debemos hacer click sobre la línea que queramos seleccionar. De forma automática se selecciona también la geometría que le corresponde.

Por ejemplo si selecciono la línea de la región The North, obtendré esta selección gráfica:

006_got

Podéis ir seleccionando las distintas líneas de la Tabla y ver su correspondencia en la cartografía. Y si queréis eliminar cualquier selección debéis utilizar la opción de “Limpiar” del menú “Selección” o su botón correspondiente:

007_got

¿Sencillo, verdad? No os olvidéis de guardar vuestro proyecto y seguiremos aprendiendo en el siguiente post…


Filed under: gvSIG Desktop, spanish, training Tagged: información alfanumérica, introducción al SIG, Juego de tronos, tabla, Tabla de atributos
Categories: OSGeo Planet

Fernando Quadro: Otimização de desempenho no GeoServer

OSGeo Planet - Tue, 2017-01-24 12:02

Neste post gostaria de falar um pouco sobre o trabalho que a equipe da GeoSolutions fez recentemente em resposta ao teste preparado pela Camp2Camp para medir e comparar desempenho e escalabilidade dos servidores GeoServer, MapServer e QGIS utilizando 3 mapas do OSM com pontos, linhas e polígonos.

Se você estiver interessado em ver a apresentação (que é em francês), você pode encontrá-la aqui; Se o seu francês é tão ruim quanto o meu, não se preocupe, as imagens importantes sobre o desempenho são auto explicativas:

a. Antes de otimizar o GeoServer

b. Depois de otimizar o GeoServer

Ok, vamos agora um pouco mais a fundo sobre o que é o teste e como você pode replicar esta experiência.

1. O Teste

O sistema é baseado em algumas imagens do docker que contêm os dados, a base de dados e o software. O repositório principal está disponível aqui:

https://github.com/camptocamp/ms_perfs

As imagens do GeoServer podem ser baixadas a partir daqui, assim como as imagens do QGIS e MapServer. Na configuração ele descarrega um mapa preciso dos dados ao redor do mundo e roda o benchmark usando gatling, através de alguns scripts shell, uma classe de teste escrito em Scala, e um script python que realiza a sumarização no final.

A instalação requer o download de todos os dados do OSM, download e compilação de vários pacotes, ou seja, podem ser necessárias várias horas para isso (dependendo de quão rápido seja sua conexão).

Uma execução de teste usa 3 camadas, cada uma com dois estilos diferentes:

  • roads-simple (linha contínua)
  • roads-dashed (linha tracejada)
  • points-simple (circulo)
  • points-class (3 arquivos svg para diferentes tipos de localização)
  • buildings-simple (polígono sólido)
  • buildings-dashed (polígono tracejado)

Cada execução funciona em locais aleatórios em 8 níveis de zoom diferentes, testando cada um separadamente e executando para 1, 2, 5, 10, 20, 40 usuários, portanto, 48 execuções, cada uma trabalhando por 120 segundos.

Cada execução usa todas as camadas em conjunto, mesmo se os relatórios finais forem em horários separados camada por camada (assim, 288 resultados no total).

Uma execução de teste funciona por 1,5 horas por servidor testado, portanto 4,5 horas no total. Os mapas no nível zoom 7 contêm muito poucos itens, e para a camada de pontos são por vezes vazios, no nível de zoom 0, em vez disso, torna-se uma “nuvem de pontos”. Veja:

c. Nivel de zoom 7:

d. Nível de zoom 0:

2. O Resultado

A configuração inicial do GeoServer tinha alguns inconvenientes que foram identificados para melhorar:

a. Utilizava as conexões máximas (10) no pool em relação ao postgresql, o que estava impedindo a escalabilidade com solicitações WMS, portanto, foi elevada. Se você estiver interessado pode encontrar algum material útil sobre isso, você pode acessar aqui, aqui e aqui.

b. Os estilos não eram exatamente iguais entre os vários servidores.

c. Os SVGs foram importados do QGIS tal como estavam, e ainda continham expressões paramétricas para cores, espessuras e opacidades, causando algumas exceções no início da execução.

d. O rasterizador não foi configurado para ser Marlin. Mais informações sobre o tema aqui e aqui.

e. A simplificação da geometria do lado do servidor que estava usando ST_Simplify, que foi desativada, já que a maioria das geometrias eram muito pequenas. Isso pode ser feito desmarcando a caixa de seleção “Suporte na simplificação da geometria da mosca” no final da configuração do Datastore (veja Imagem abaixo).

Como de costume quando se faz este tipo de experiência geralmente encontra-se uma boa maneira de otimizar o GeoServer. Neste caso, foram realizadas algumas melhoras na versão Master do GeoServer, veja:

f. Envio com renderizador Marlin: Devemos enviar o Marlin Renderer entre os jars do GeoServer por padrão, ativar seu uso nos instaladores bin / win / osx, quando o JDK for menos que 1.9.

g. Otimizar a transferência de dados do PostgreSQL: Atualmente nós transferimos dados utilizando o formato WKB, no entanto desde o PostGIS 2.2 temos disponível o TWKB que parece reduzir significativamente a carga útil transferida.

O ST_RemoveRepeatedPoints parece ser também bastante interessante, com pouca sobrecarga, podemos usar por padrão a partir da versão 2.2. do postgis e ter uma flag separada para o uso do ST_Simplify (que é mais pesado). O segundo deve ser ativado na base de dados, talvez considerando também intervalos de escala.

h. Representação dos polígonos: Polígonos em java2d parece ser ainda significativamente mais lento do que no MapServer, isso é algo que é necessário tentar melhorar no nível da JDK.

Fonte: GeoSolutions Blog

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Categories: OSGeo Planet

GeoServer Team: GeoServer Code Sprint 2017

OSGeo Planet - Mon, 2017-01-23 19:04

GeoSolutions has 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 glamorous 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. GeoSolution’s 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

gvSIG Team: Aprendiendo SIG con Juego de Tronos (I): Añadir datos a un proyecto

OSGeo Planet - Mon, 2017-01-23 17:34

Esta serie de post pretenden que, sin conocimientos previos y mediante una serie de ejercicios prácticos, aprendamos a manejar un SIG. Para hacer más ameno el aprendizaje vamos a utilizar una serie de capas relacionadas con el mundo de ficción de Juego de Tronos. Y como software utilizaremos gvSIG Desktop, un SIG libre utilizado en más de 160 países. Serán post muy sencillos y en los que iremos poco a poco profundizando en las herramientas fundamentales de un Sistema de Información Geográfica. Empezaremos hoy con algo muy básico, añadir ficheros con datos cartográficos.

Podéis descargaros tanto los instaladores como las versiones portables para los distintos sistemas operativos en la web de la Asociación gvSIG. Si tenéis cualquier problema con la instalación o con el uso del software podéis utilizar la lista de usuarios para comunicaros con el resto de la comunidad y recibir su soporte.

Los datos que utilizaremos durante esta serie de post pueden ser descargados de aquí.

En primer lugar abrimos nuestro gvSIG. Veremos la interfaz con los siguientes componentes:

001_got

  1. Barra de menús.
  2. Barra de botones.
  3. Gestor de proyecto. Permite gestionar todos los documentos que componen un proyecto.
  4. Espacio de trabajo. En este espacio podremos tener abiertos los distintos documentos de un proyecto y trabajando con ellos.
  5. Barra de estado. Espacio destinado a dar información al usuario.

El documento que nos interesa es el llamado “Vista”. Permite trabajar con datos gráficos. En una Vista la información geográfica se representa como un conjunto de capas.

Como por defecto el documento “Vista” está seleccionado (está como iluminado) tan sólo debemos pulsar el botón “Nuevo” y nos aparecerá una nueva Vista. Maximizamos la ventana.

Ahora vamos a añadir capas a nuestra Vista. Para eso simplemente debemos pulsar el botón de “Añadir capa”, que podemos encontrar en el menú “Vista” o en el botón:

002_got…se abre una ventana con distintas pestañas, que no son más que las distintas fuentes de información cartográfica posibles (nosotros nos centraremos en la primera, “Archivo”).

003_got

Vamos a pulsar el botón “Añadir” para cargar nuestra primera capa. Para ello vamos a buscarla en nuestra carpeta de datos, seleccionando el fichero “Land.shp”. Este fichero (podéis comprobarlo desde un navegador de archivos) viene acompañado de uno llamado “Land.gvsleg” que contiene una leyenda predefinida. Por tanto se cargará de color verde y sin fondo (ya veremos en otro post como cambiar una leyenda). Representa la zona de tierra conocida de Juego de Tronos. En la parte izquierda (llamada tabla de contenidos) de la Vista veréis como aparece el nombre de la capa con su leyenda.

Pulsando sobre el nombre de la capa con el botón derecho nos aparecerá un menú contextual que incluye la opción “Añadir a localizador”. La seleccionamos y vemos que la misma capa aparece en el cuadro inferior izquierdo. El localizador mostrará en un rectángulo rojo el área visible de la Vista.

Ahora que ya sabemos añadir capas vamos a añadir la capa Islands, Landscape, Lakes, y Rivers. Arrastrando y soltando cada una de las capas en la Tabla de contenidos podemos cambiar su orden de visualización. Con esto ya tendríamos un mapa físico de Juego de Tronos.

Por último vamos a cambiar el color de fondo de la Vista de blanco a un tono azulado, lo que nos permitirá identificarlo visualmente como mar. En el menú “Vista” seleccionamos la opción “Propiedades”. En la nueva ventana que se abre veremos que hay una opción que nos permite cambiar el color de fondo.

El resultado final será similar al siguiente:

got_001Guardad vuestro proyecto y nos vemos en el siguiente ejercicio…


Filed under: gvSIG Desktop, spanish, training Tagged: añadir capa, cargar capa, fondo de Vista, introducción al SIG, Juego de tronos, localizador, tutorial
Categories: OSGeo Planet

GeoSolutions: Developer’s Corner: Latest performance optimizations in GeoServer

OSGeo Planet - Mon, 2017-01-23 14:00

GeoServer Performance

Dear Readers,

in this post we would like to describe work that our GeoServer Technical Lead Andrea Aime, has done recently in response the test harness prepared by Camp2Camp to measure and compare performance and scalability of GeoServer, MapServer and QGIS Server against 3 OSM derived maps with points, lines and polygons. If you are interested the presentation (which is in French) you can find it here; if your French is as bad as mine, don't worry, the important pictures about performance are self explaning:

[caption id="attachment_3200" align="alignnone" width="600"]Before optimizations Before optimizing GeoServer[/caption] [caption id="attachment_3201" align="alignnone" width="600"]After Optimizations After optimizing GeoServer[/caption] Ok, let us now go a little more in detail on what the test harness is about in case you wanted to replicate the experiment. Test Harness The overall system is based on a few docker images containing both the data, database and the software. The main repository is here:

https://github.com/camptocamp/ms_perfs

The GeoServer images are pulled from https://github.com/camptocamp/docker-geoserver, similar images are available for QGIS and MapServer. The setup downloads an accurate map of swiss plus extra data around the world and runs the benchmark on it using gatling, driven by some shell scripts, a test class written in Scala, and a python summarization script at the end.

The setup requires to download all the OSM data, download and compile various packages, so a few hours might be needed for it (depending on how fast your network connection is). A test run uses 3 layers, each with two different styles:
  • roads-simple (continous line)
  • roads-dashed (dashed line)
  • points-simple (circle)
  • points-class (3 svg files for different type of locations)
  • buildings-simple (solid fill and stroke)
  • buildsing-dashed (dashed fill and simplestroke)

Each run  works  at random locations at 8 different zoom levels, testing each separately, and run for 1, 2, 5, 10, 20, 40 users, thus 48 runs, each one working for 120 seconds. Each run uses all the layers together, even if the final reports give separate timings layer by layer (thus, 288 results in total, the graphs above average the results for various zoom level into a single number).

A test run works for 1.5 hours long per tested server, so 4.5 hours total. Patience and something else to do in the meantime are thus prerequisites.  The maps at level zoom 7 contain very few items, and for the points layer are sometimes empty, at zoom level 7 instead it becomes a “point cloud”. E.g., zoom level 7:

[caption id="attachment_3195" align="alignnone" width="700"]zoom level 7 zoom level 7[/caption]

zoom level 0:

[caption id="attachment_3196" align="alignnone" width="700"]zoom level 0 zoom level 0[/caption]

Findings

The initial configuration of GeoServer had a few drawbacks that we have helped spot and improve:

  • It w as using the default max 10 connections in the pool towards postgresql which was hindering scalability with WMS requests against it, hence we raised it. If you are interested you can find some useful material here, here and here.
  • The styles were not an exact match between the various servers.
  • The SVGs were imported from QGIS as is, and still contained parametric expressions for colors, thicknesses and opacities, causing some exceptions at the beginning of the run.
  • The rasterizer was not setup to be Marlin. More information on the topic in this post and here.
  • The server side geometry simplification using ST_Simplify was turned off as most geometries are very small to start with. This can be done by unchecking the "Support on the fly geometry simplification" checkbox at the end of the Datastore configuration (see Image below).
[caption id="attachment_3199" align="alignnone" width="400"]geometry simplification geometry simplification[/caption]

As usual when we do this kind of experiments we find usually nice way to optimize GeoServer by hitting code making use of a code profiler; in this case the following came out and have been improved on GeoServer Master:

Further Potential Improvements Actions (i.e. want to help to make GeoServer better?)

Shipping with Marlin Renderer: we should ship Marlin Renderer among the GeoServer jars by default, enable its usage in the bin/win/osx installers, provide information on how to set it up in other containers in the docs or even as a warning in the GUI (the admin ones) if we detect a JDK < 1.9.

Optimizing data transfer from PostgreSQL: currently we transfer data as WKB, however since PostGIS 2.2 we have TWKB available that seems to significantly reduce the payload transferred. The ST_RemoveRepeatedPoints seems to be also quite interesting, very little overhead, we could use that one by default for postgis >= 2.2 and have a separate flag for the usage of ST_Simplify (which is instead heavy). The second should be enabled on a per dataset basis, maybe considering also scale ranges. Finally, now the code is encoding base64 the binary because old postgresql drivers were limited to text based transfers and they did so by doubling the size of the payload, when base64 only make it 4/3 of the original size). Recent drivers allow to configure pure binary transfer instead, we should explore how it gets enabled (there are parameters), its relationship with prepared statements and see if we can effectively leverage it.

Polygon rendering: polygon filling/stroking in java2d appears to be still significantly slower than in MapServer, this is something we could try to improve at the JDK level.

If you are interested in learning about how we can help you achieving your goals with open source products like GeoServerMapstore, GeoNode and GeoNetwork through our Enterprise Support Services and GeoServer Deployment Warranty offerings, feel free to contact us!

The GeoSolutions team,
Categories: OSGeo Planet

Gis-Lab: Опыт классификации космоснимка Sentinel- 2a с помощью Semi-Automatic Classification Plugin в QGIS

OSGeo Planet - Mon, 2017-01-23 09:07

Новая статья описывает опыт работы с Semi-Automatic Classification Plugin для QGIS для классификации снимка космоснимка Sentinel- 2a с целью выявления лесонарушений на примере национального парка “Орловское полесье”, а также содержит пошаговую инструкцию для лесного дешифрирования снимка с помощью данного плагина.

Автор: Карпачев Андрей Петрович, научный сотрудник НП “Орловское полесье”.

Прочитать | Обсудить

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Categories: OSGeo Planet

From GIS to Remote Sensing: Direct Editing of a Raster Using The Semi-Automatic Classification Plugin

OSGeo Planet - Mon, 2017-01-23 06:05
This tutorial describes the SCP tool Edit raster that allows for the direct editing of pixel values in a raster. Direct editing is very convenient in case of large rasters, reducing the computational time and easing the process of updating a raster such as land cover classification.In this tutorial we are going to edit a very large raster, which is the Corine Land Cover referred to year 2006 (but it is available also for 1990, 2000 and 2012). This raster is produced by the European Environment Agency (EEA), and covers the whole European Countries with a spatial resolution of 100m and a very detailed classification system. For more information read this page .
Categories: OSGeo Planet

gvSIG Team: 12as Jornadas Internacionales gvSIG. Ponencias y talleres disponibles

OSGeo Planet - Fri, 2017-01-20 11:31

12as_j_gvsig_es-ponenciasYa se encuentran disponibles las presentaciones realizadas en las 12as Jornadas Internacionales gvSIG, que se celebraron del 30 de noviembre al 2 de diciembre de 2016 en Valencia (España).

También está disponible la grabación de las mismas y de los talleres para ser visualizados online. Los vídeos se encuentran disponibles en su idioma original, habiendo presentaciones y talleres en español e inglés. Los talleres que se impartieron durante las jornadas, de los cuales está disponible la grabación para poder seguirlos, fueron sobre “Introducción a gvSIG”, “gvSIG aplicado a Topografía”, “Introducción al desarrollo en gvSIG con Scripting” y “Novedades gvSIG 2.3”, todos ellos en español, y “Geopaparazzi and gvSIG” en inglés.

En ellos se puede encontrar también toda la información sobre el material necesario para poder seguirlos.

Con la publicación de estos vídeos pretendemos acercar las Jornadas a todos aquellos interesados que no pudieron asistir, teniendo ahora la posibilidad de acceder a la grabación de las distintas sesiones y talleres.


Filed under: community, events, spanish, training
Categories: OSGeo Planet
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