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Quantum GIS (QGIS) Tutorials

Quantum GIS (QGIS) Tutorials
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QGIS Styling Vector Data Please see Basic Vector Styling for an updated version of this tutorial. To create a map, one has to style the GIS data and present it in a form that is visually informative. There are a large number of options available in QGIS to apply different types of symbology to the underlying data. In this tutorial, we will explore some basics of styling.The data we will use is from Center for Sustainability and the Global Environment (SAGE) at the University of Wisconsin-Madison. We will explore many more options and the Rule-based styling method in a subsequent tutorial.

Export for print | QGIS basics for Journalists QGIS export happens in the print dialog box. You can save your map as an image or one of two formats than can be read in Adobe Illustrator. Go to the File menu and select New Print Composer. Set your page size and orientation. Next, click the Add Map button and click and drag a box to add the map to your page. Both PDF and SVG can usually be opened and edited in Illustrator. Filed under: Maps, Data Visualization Quantum GIS 1.6: Preenchimento Automático de Campo Repare na seguinte Tabela de Atributos: Que tal criar rapidamente uma coluna índice para essa tabela? Esse procedimento ja foi demonstrado no BrOffice Calc e gvSIG. Para prosseguir, primeiro entre no Modo de Edição do Quantum GIS 1.6: Com a Tabela de Atributos aberta, clique no botão Calculadora de Campo: Indique um Nome para a coluna, o Tipo de Dado e a Largura do Campo. Como num passe de mágica, surge uma coluna numerada na tabela. Finalize a edição e aproveite um dos novos recursos da versão 1.6 do QGIS.

QGIS Raster to vector and Change projection —Contribute to this tutorial by completing one section welcome ! Projection (0%)[edit] → waiting a volunteer Equirectangular projection of the world; the standard parallel is the equator (plate carrée projection). Background QGIS display your data using the projection you tell it to use. Source projection First, you have to find the definition of your source projection/file. QGis (1.7) > (double click on the layer to reproject) > Layer's properties (window pop up) > tab 'Coordinates Reference System (CRS)' > Layer Spatial Reference System : [projection's definition] > (copy it) In progress Which new projection for my map ? Secondly, you have to choice your target projection. In progressTarget projection Third, you have to find the definition of this target projection. QGis (1.7) > File > Project's properties (a window pop up) > tab 'Coordinates Reference System (CRS)' >> Select your target projection* > copy the definition (the long equation) > >> ? Reproject a raster layer Reproject a vector layer

Making simple map images with qGIS | Neogeo ramblings with a Python twist Occasionally you just need a quick map, and it’s not going to be used for interaction or even necessarily display on the internet (say a Keynote/PowerPoint presentation, for example). We could build it as a Google map, get a gigantic computer monitor and fullscreen the window and take a screenshot, and have it look like every other web map out there – or we can reach into the toolbox of those who are NOT neogeographers and borrow a few things. For me this tool is still qGIS (for Mac check out KyngChaos for binary builds), though there are alternatives like GRASS GIS and TileMill, to name only a couple. (TileMill is actually designed to create tiles similar to how Google Maps / OpenStreetMap do it, but you can shoehorn it to do “print” maps) Of course, it bears repeating that the results from doing this are not survey quality. Since this is a process with no code, I’m switching format a bit and creating a screencast, which you can see here as a QuickTime file.

QGIS | Opening raster files QGIS understands three major forms of data. Two of these are spatial (ie, they contain information allows it to be shown in space) and the third contains no spatial data (" aspatial data") The two spatial data types are: Vector data. This technical note shows a process for adding a raster layer to your QGIS project --- and it's easy.mActionAddRasterLayer.pngPlugins : None Description¶ Click on the the Add Raster Layer button Add raster layer button Fill in the box. A completed dialogue box that will open the Alaska Landcover image Once everything is filled in on the main dialogue, just hit open and you're done. The Alaska landcover image Notes¶

Stamen Maps for QGIS Stamen’s maps are amongst the most creative and beautiful OpenStreetMap visualizations and it would be great to have them as base maps in QGIS. No problem! Nathaniel Kelso has already done all the work for us and we can download the extended OpenLayers plugin from his Github page. (There is a pull request in place to add Stamen to the default plugin too.) Simply unpack the plugin into QGIS’ plugin folder. It adds the possibility to load Stamen’s Watercolor, Toner and Terrain tiles into the QGIS project: Like all other OpenLayers layers, these can now be overlaid with more data such as this heatmap which is based on Twitter data I presented in a previous post, processed using Heatmap plugin and semi-transparently overlaid onto Stamen’s Toner map: Like this: Like Loading...

Digitizing Errors in GIS Digitizing in GIS is the process of converting geographic data either from a hardcopy or a scanned image into vector data by tracing the features. During the digitzing process, features from the traced map or image are captured as coordinates in either point, line, or polygon format. Types of Digitizing in GIS There are several types of digitizing methods. Types of Digitizing Errors in GIS Since most common methods of digitizing involve the interpretation of geographic features via the human hand, there are several types of errors that can occur during the course of capturing the data. During the digitizing process, vectors are connected to other lines by a node, which marks the point of intersection. Dangles or Dangling Nodes Dangles or dangling nodes are lines that are not connected but should be. An open polygon caused by the endpoints not snapping together. Switchbacks, Knots, and Loops Example of a weird polygon where the line folds back on itself. Overshoots and Undershoots Slivers