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QGIS to use CMEMS information

This slideshow is intended to present the CMEMS Ocean Model Capacity LEVEL2 – ADVANCED LEVEL- Slides have been prepared in Janv 2017

pace DD/MM/YYYY, Name of the event, Place

OUTLINES

• IMPORT OF PLUGINS FROM THE ONLINE

REPOSITORY

• VISUALISE CURRENTS/WIND SPEED

• CREATE ISO-CONTOURS

• USE THE MAP COMPOSER

pace DD/MM/YYYY, Name of the event, Place

OUTLINES

• IMPORT OF PLUGINS FROM THE ONLINE

REPOSITORY (http://plugins.qgis.org/plugins/) • NetCDF Browser

• Vector Field Calc

• Vector Field Renderer

• Contour plugin

• Point Sampling Tool

• VISUALISE CURRENTS/WIND SPEED

• CREATE ISO-CONTOURS

• USE THE MAP COMPOSER

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Import of plugins from the online repository

http://plugins.qgis.org/plugins/

NetCDF Browser

Vector Field Calc

Vector Field Renderer

Contour plugin

Point Sampling Tool

1. Click to open the Plugins Window

2. Be assured you are connected to the repository online

3. Search the plugin you want to install

4. Choose your plugin

5. Install it

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How to visualize the currents/wind speed (1/4)

Display Estward and Northward velocities (u+v) components from a .nc file

The Regular points tool:

1. Create or import a grid point (.shp format)

2. Choose an area of the input boundary layer or input coordinates

3. Enter a grid spacing: space between each point (depends of the raster resolution)

4. Define an output .shp file

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How to visualize the currents/wind speed (2/4)

Sample the grid point with the Point Sampling Tool

1. Choose the point grid created previously as the layer containing sampling points

2. Select the layers with bands to get values from : Eastward+Northward velocities (u+v)

3. Output point vector layer (.shp)

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How to visualize the currents/wind speed (3/4)

1. Transform the points to arrows with the Vector Field Renderer plugin

2. Open the Properties of the layer (Style folder): Vector field

3. Select the Vector field type: Cartesian field (u field as X attribute and v field as Y attribute fields)

4. Define the arrow size and the colour

7. Define the scale and the legend

8. Define the layer rendering

Thanks to u and v values combined, arrows represent both intensity (magnitude in m/s) and current direction (orientation from 0 to 360°) with proportional symbol

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How to visualize the currents/wind speed (3/4)

1. Calculate the magnitude from u and v as input rasters with the VectorFieldCalc plugin

2. Check Magnitude and create a new file in ascii format

3. Click on the button Calculate

4. Put in the background the magnitude and bring to the foreground the arrows.

5. Apply a color palette on the magnitude

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pace DD/MM/YYYY, Name of the event, Place

OUTLINES

• IMPORT OF PLUGINS FROM THE ONLINE

REPOSITORY

• VISUALISE CURRENTS/WIND SPEED

• CREATE ISO-CONTOURS

• USE THE MAP COMPOSER

pace

How to create iso-contours (1/3)

The Regular points tool:

1. Create or import a grid point (.shp format)

2. Choose an area of the input boundary layer or input coordinates

3. Enter Grid spacing: space between each point (depends of the raster resolution)

4. Define an output vector file (.shp)

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How to create iso-contours (2/3)

Sample the grid point with the Point Sampling Tool

1. Choose the point grid as the layer containing sampling points

2. Select the layers with bands to get values from

3. Create an output point vector layer (.shp)

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How to create iso-contours (3/3)

Draw iso-contours with the Contour plugin

1. Select input data: .shp file with the data field corresponding to contour creation

2. Select the contour lines, the number of lines. Minimum and maximum are adjusted automatically

3. Create the output data: the layer name is auto generated. Apply the same colour palette as the raster one for a smoother rendering

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pace DD/MM/YYYY, Name of the event, Place

OUTLINES

• IMPORT OF PLUGINS FROM THE ONLINE

REPOSITORY

• VISUALISE CURRENTS/WIND SPEED

• CREATE ISO-CONTOURS

• USE THE MAP COMPOSER

pace

How to use the map composer (1/2)

How to create a map: 1. Click on New print composer

2. Create a Composer title

3. Open a template and save it after creation

4. Save as image (png), svg or pdf

5. Zoom full extent, zoom in, zoom out, refresh

6. Move objects, change the size

7. Move, zoom or extent the content frame

8. Add a new map and display data of the QGIS canvas automatically

9. Add an image, logo

10.Add a title

11.Add a legend

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How to use the map composer (2/2)

1. Open a template

2. Choose a .qpt format

3. Composition properties: paper format and quality

4. Item properties: Possibility to update the map position, the legend, the title, the logo, the grid…

5. Generate an atlas

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Cliquez et modifiez le titre Any question, any time :

servicedesk.cmems@mercator-ocean.eu