QGIS/C2/Coordinate-Reference-Systems/English
Visual Cue | Narration |
Slide Number 1
Title Slide |
Welcome to this tutorial on Coordinate Reference System in QGIS. |
Slide Number 2
Learning Objectives |
In this tutorial, we will learn to,
Add layers to projections in QGIS. View metadata information for layers. Save selected features from a layer to a new layer. Re-project and overlay data layers of different projections together.
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Slide Number 3
System Requirement |
To record this tutorial I am using,
Ubuntu Linux OS version 16.04 QGIS version 2.18 |
Slide Number 4
Pre-requisites
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To follow this tutorial you should have basic knowledge about GIS.
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Slide Number 5
Coordinate Reference systems |
About Coordinate Reference Systems,
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Slide Number 5
Coordinate Reference systems |
Most widely used geographic coordinate system is WGS 84.
Most widely used projected coordinate system is UTM (Universal Transverse Mercator).
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Click on QGIS icon to open the interface.
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Here I have opened QGIS interface.
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Slide Number 6
World Map File |
Demonstration on how to download the map,
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Cursor on layers panel on name of the map file. | On the left-side of the canvas,you will see Layers Panel,
with file name of the world map as a layer.
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Cursor on the canvas. | By default Layers Panel is enabled here.
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Click on View tool on the Tool bar.
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Click on View menu on the menu bar.
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Scroll down and select Panels option.
From the sub-menu, click on Layer Panel. |
Sub-menu shows a list of panel names.
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Drag the boundary with the mouse. | We can adjust the size of the panel by dragging the boundary. |
Right-click on the layer name in Layers Panel.
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If you wish to change the color of the map,
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Scroll-down the context menu and select Styles option.
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Scroll-down the context menu and select Styles option.
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Click anywhere on the canvas. | Click anywhere on the canvas to close the context menu. |
Cursor on Coordinate label and text box.
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At the bottom-left corner, on the status bar, of QGIS window,
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Highlight X and Y coordinates. (Editing stage) | Values of X and Y coordinates for a particular location are shown in this text box. |
Move the cursor over the map.
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Move the cursor over the map.
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Cursor on Render option. | By default Render option is checked on the status bar.
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Point towards EPSG:4326(OTF) on the bottom-right corner of the status bar. | On the status bar, at the bottom-right corner,
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To determine a layer’s projection, we can look into the metadata. | |
Right click on the Layers Panel, ne_10m_admin_0_countries
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On the Layers Panel,
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From the context menu, select Properties.
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From the context menu, select Properties.
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Click on Metadata option in Layer dialog-box.
Scroll down. |
In the dialog-box, on the left-side panel, click on Metadata option.
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Point to heading, Layer Spatial Reference System.
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At the bottom,
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Click Ok button | Click on Ok button, to close the dialog box. |
Let us now add layers to the map and change the projection. | |
Slide Number 7
Data layers |
About data layers.
Usually geographical data is stored in layers in a GIS workspace. Each layer has data stored in its attribute table. Many layers can represent data of the same geographical location.
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Back to the QGIS interface. | |
Cursor on the QGIS canvas. | Now let us see how we can change the layer’s projection.
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On top-right corner of the tool bar,
Click on the Select features by area or single click tool.
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On top-right corner of the tool bar,
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On the canvas, on the world map, click on United States of America. | On the world map displayed on canvas,
The United States of America is shown in a different color. |
Cursor on the map. | We will now change the projected coordinate system of this layer and save.
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Right click on ne_10m_admin_0_countries | Right-click on the layer name in the Layers Panel. |
Click on Save As option | Scroll down, Select Save As option. |
Save Vector Layer as Dialog box opens.
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Save Vector Layer as... Dialog box opens.
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Click on Browse button. | Click on Browse button next to File name text box. |
Save layer as... dialog-box opens.
In the name text box type the layer as USA-1.shp. |
Save layer as... dialog-box opens.
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Click on Desktop option.
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Find a suitable location to save.
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In the Save Vector Layer as... dialog-box.
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In the Save Vector Layer as.... dialog-box,
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Click select CRS button next to CRS text box.
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We will choose the new projection for this layer.
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In the Coordinate Reference System Selector dialog box,
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In the Coordinate Reference System Selector,
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Click North_America_Albers_Equal_Area_Conic
Click on OK button.
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Under Coordinate reference systems of the world,
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Click on OK button. | Click on OK button. |
In the Save vector layer as... dialog-box, cursor on CRS drop down box. | In the CRS drop down box, the newly selected CRS is shown. |
In the Save Vector Layer as dialog-box,
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Click on the check box to check Save only selected features option.
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Cursor on , Add saved file to map. | Here, by default, Add saved file to map option is checked.
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In the Save Vector Layer as... dialog-box, click on OK button | Click on OK button |
Point on united states outline.
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The re-projected layer gets loaded,
in a different color.
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untick enable on the fly CRS transformation
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Notice that the new united states layer overlays perfectly on top of the world map layer.
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At the bottom-right corner, click on EPSG:4326.
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Select United-States layer in the Layers Panel by clicking on it.
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Cursor on Project Properties CRS dialog-box. | Project Properties CRS dialog-box opens.
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Uncheck Enable on the fly CRS transformation check box,
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Uncheck Enable on the fly CRS transformation check box, by clicking on it.
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Cursor on the map. | Back in the main QGIS window, you will see the world map disappear.
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Right click on USA-1.shp layer.
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The coordinates and scale are different now.
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Click on EPSG
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Again, click on the Current CRS text to open Project Properties dialog-box.
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Under the heading Recently used Coordinate Reference Systems,
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Under the heading Recently used Coordinate Reference Systems,
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Right-click on USA-1.shp in Layers panel.
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To delete the vector layer from the dataset,
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Click on Remove option from the context menu.
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From the context menu, click on Remove option.
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Cursor on the layers panel. | Observe that the layer is removed from the dataset. |
Slide Number 10
Summary |
Let us summarize,
In this tutorial we have learnt to
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Slide Number 11
Assignment |
As an Assignment
Project The United States with North_America_Lambert_Conformal_Conic projection and observe the difference. Re-project the entire world map layer into World Mecator projection system.
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Show completed assignments. | Your completed assignment should look like this. |
Slide Number 12
About Spoken Tutorial project |
The video at the following link summarizes the Spoken Tutorial project.
Please download and watch it.
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Slide Number 13
Spoken Tutorial workshops |
The Spoken Tutorial Project team:
conducts workshops using spoken tutorials and gives certificates on passing online tests. For more details, please write to us. |
Slide number 14
Forum for specific questions:
•Please visit this site •Choose the minute and second where you have the question •Explain your question briefly •Someone from our team will answer them
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Please post your timed queries on this forum. |
Slide Number 16:
Acknowledgement |
Spoken Tutorial Project is funded by NMEICT, MHRD, Government of India.
More information on this mission is available at this link. |
This tutorial is contributed by Prajwal. M from Sahyadri college of Engineering and Snehalatha from IIT Bombay.
Thank you for joining |