View source for QGIS/C2/Coordinate-Reference-Systems/English

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||'''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.

|-
|| '''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'''

*'''Basic knowledge about GIS.'''
*Please view pre-requisite tutorial in this series.
|| To follow this tutorial you should have basic knowledge about '''GIS.'''


Please view previous tutorial in this series.

|-
|| '''Slide Number 5'''

'''Coordinate Reference systems'''
|| About '''Coordinate Reference Systems''', 


'''Coordinate Reference Systems''' are of two types,

*'''Geographic coordinate system'''
*'''Projected Coordinate System'''

|-
|| '''Slide Number 5'''

'''Coordinate Reference systems'''
||Most widely used '''geographic coordinate system''' is '''WGS 84.'''

Most widely used '''projected coordinate system''' is '''UTM'''.

|-
|| Click on '''QGIS''' icon to open the interface.


Cursor on Canvas.
|| Here I have opened '''QGIS''' interface.


On the '''canvas''', world map with country administration boundaries is displayed.

|-
|| '''Slide Number 6'''

'''World Map File'''
|| Demonstration on how to download the map and display in '''QGIS''' is explained in the prerequisite tutorial.


Please view the pre-requisite tutorial.


This file can also be downloaded from the '''Code files''' link.

|-
|| 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'''.

|-
|| Cursor on the canvas.
|| By default '''Layers Panel''' is enabled here.


If not, we can enable or disable the '''Layers Panel '''using '''View''' menu.

|-
|| Click on '''View''' tool on the Tool bar.



|| Click on '''View''' menu on the '''menu''' bar.


Scroll down and select '''Panels '''option.

|-
|| Scroll down and select '''Panels '''option.

From the sub-menu, click on '''Layer Panel'''.
|| Sub-menu shows a list of '''panel''' names.


Click on '''Layer Panel''' option to enable or disable the '''panel'''. 

|-
|| 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.'''


|| If you wish to change the color of the map, right-click on the '''layer''' name in the '''Layers Panel.'''

|-
|| Scroll-down the '''context menu''' and select '''Styles''' option.
|| Scroll-down the '''context menu''' and select '''Styles''' option.

|-
||Rotate the vertex of the color triangle to choose the color.


||Sub-menu shows a color triangle .


Choose the color by rotating the vertex of the color triangle.

|-
|| Click anywhere on the canvas.
|| Click anywhere on the '''canvas''' to close the context menu.

|-
|| Cursor on''' Coordinate label '''and text box.



|| At the bottom-left corner, on the '''status''' bar of '''QGIS''' window, you will notice 
*the label '''Coordinate '''
*and a text box with numbers.

|-
|| 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.


Point 
|| Move the cursor over the map. 


Observe, that the values of '''X''' and '''Y coordinates''' change with the location of the cursor.

|-
|| Cursor on '''Render '''option.
|| By default '''Render '''option is checked on the '''status bar'''.


Leave it as such.

|-
|| Point towards '''EPSG:4326(OTF) '''on the bottom-right corner of the status bar.
|| On the '''status bar''', at the bottom-right corner, you will see another '''label, Current CRS.'''


This code represents the current '''Projection Coordinate Reference System.'''

|-
|| 
|| To determine a '''layer’s projection''', we can look into the '''metadata'''.

|-
|| Right click on the Layers Panel, '''ne_10m_admin_0_countries'''
|| On the '''Layers Panel''', right-click on the '''layer''' name.

|-
|| From the context menu, select '''Properties'''.


|| From the context menu, select '''Properties'''.


'''Layer Properties''' dialog-box opens.

|-
|| Click on '''Metadata''' option in '''Layer''' dialog-box.


Click on back arrow next to properties.

Scroll down.
|| In the dialog-box, on the left-side panel, click on '''Metadata''' option.


Under '''Properties '''section, scroll down the slider.

|-
|| Point to heading, '''Layer Spatial Reference System.'''


Point to '''WGS84'''.



|| At the bottom, 

*under heading, '''Layer Spatial Reference System,'''
*you will see the definition for this projection.


It shows '''WGS84 '''as '''geographic coordinate system.'''

|-
|| Click '''Ok''' button
|| Click on '''Ok''' button at the bottom, 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.

|-
|| 
|| Back to the '''QGIS''' interface.

|-
|| Cursor on the QGIS canvas.
|| Now let us see how we can change the '''layer’s projection.'''


This operation is called '''Re-Projection.'''


Instead of re-projecting the entire '''layer''', we will re-project some features.

|-
|| On top-right corner of the tool bar >> click on '''Select features by area or single click '''tool.
|| On top-right corner of the tool bar, 


Click on '''Select features by area or single click '''tool.

|-
||Click on the black triangle next to this tool.
||Click on the black triangle next to this tool. 

|-
||Drop down >> choose '''Select features'''.
||From the drop down choose '''Select features'''.

|-
|| On the canvas, on the world map, click on '''United States of America.'''
|| On the world map displayed on '''canvas''', click on the '''United States of America''' feature to select it.


Note that, 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. 

|-
|| 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.



|| '''Save Vector Layer as... '''dialog box opens.


The default '''format '''option is '''ESRI Shapefile.''' 

Leave it as such.

|-
|| 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.


Name the output '''layer''' as '''USA-1.shp.'''

|-
|| Click on '''Desktop''' option.


Click on '''Save''' button. 
|| Find a suitable location to save.

I will save it on '''Desktop'''

Click on '''Save''' button at the bottom. 

|-
|| In the '''Save Vector Layer''' '''as...''' dialog-box.


Point to '''File name '''text box.
|| In the '''Save Vector Layer as....''' dialog-box, the '''file path''' appears in the '''File name''' text box.

|-
|| Click select '''CRS''' button next to '''CRS''' text box.



|| We will choose the new '''projection''' for this '''layer'''.


Next to the '''CRS''' drop down box, click on '''Select CRS '''button. 

|-
|| In the '''Coordinate Reference System Selector''' dialog box, type '''North America'''


|| 
*In the '''Coordinate Reference System Selector''',
*In the '''Filter search box''', enter '''North America''' 

|-
|| Click '''North_America_Albers_Equal_Area_Conic'''



|| 
*Under '''Coordinate reference systems''' of the world, 
*Under heading '''Projected Coordinate System, '''
*Scroll through the results.


Select, '''North_America_Albers_Equal_Area_Conic (EPSG:102008) projection'''.

|-
|| Click on '''OK''' button.
|| Click on '''OK''' button at the bottom.

|-
|| 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,


Click on the check box next to '''Save only selected features.'''
|| Click on the check box to check '''Save only selected features '''option.


This will ensure that only the selected '''feature''' gets '''re-projected''' and '''exported'''.

|-
|| Cursor on , '''Add saved file to map.'''
|| Here, by default, '''Add saved file to map '''option is checked.


If not, click on the check box to check this option.

|-
|| In the '''Save Vector Layer''' '''as...''' dialog-box, click on '''OK '''button 
|| Click on '''OK '''button at the bottom.

|-
|| Point on '''united states''' outline.


Cursor on '''Layers panel'''.
|| The '''re-projected layer''' gets loaded, in a different color.


These two '''layers''' are now in different '''projections'''.


Observe that, on '''Layers Panel,''' you can now see 2 entries.

|-
|| untick enable '''on the fly CRS transformation'''


'''Point to OTF next to EPSG:4326.'''
|| Notice that the new '''United States layer''' overlays perfectly on top of the '''world map layer'''.


This is because '''QGIS''' has a '''feature''' called '''On-the-fly CRS transformation.'''


The '''projection''' text at the bottom-right of '''QGIS''' window has the words, '''OTF '''next to '''EPSG:4326'''.

|-
|| At the bottom-right corner, click on '''EPSG:4326'''.



|| Select '''United-States''' layer in the '''Layers Panel '''by clicking on it.


Click on the '''Current CRS''' text, '''EPSG:4326,''' at the bottom-right corner of the '''status''' bar.

|-
|| Cursor on '''Project Properties CRS''' dialog-box.
|| '''Project Properties CRS''' dialog-box opens.


Let us turn-off the '''Enable on-the-fly CRS transformation''' and see what happens.

|-
|| Uncheck '''Enable on the fly CRS transformation '''check box, 



|| Uncheck '''Enable on the fly CRS transformation '''check box, by clicking on it.


Click on '''OK '''button at the bottom.

|-
|| Cursor on the map.
|| Back in the '''main QGIS''' window, you will see the world map disappear.


You can see only '''United States''' map on the '''canvas'''.


This is because the '''Projected CRS''' for this '''layer''' changed to '''Albers Projection.'''

|-
|| Right click on '''USA-1.shp''' layer.


Select zoom to layer
|| The '''coordinates''' and scale are different now.


Right-click the''' United States layer''' in the '''Layers Panel.'''


Select''' Zoom to Layer '''option.


Now you will see the '''United States''' in the selected '''projection'''.

|-
|| Click on '''EPSG'''


Tick '''Enable on the fly CRS transformation.'''
|| Again, click on the '''Current CRS''' text to open '''Project Properties''' dialog-box.


Turn-on the''' Enable ‘on the fly’ CRS transformation''' option.

|-
|| Under the heading '''Recently used Coordinate Reference Systems,''' select '''WGS 84.'''


Click on''' OK '''button.
|| Under the heading '''Recently used Coordinate Reference Systems,''' select '''WGS 84'''.

And click on '''OK '''button at the bottom.


The display on the '''canvas''' will return to its previous state with world map.

|-
|| Right-click on USA-1.shp in Layers panel.


|| To delete the '''vector layer''' from the '''dataset''', right-click on the name in '''Layers panel'''. 

|-
|| Click on '''Remove''' option from the context menu.


Click on '''OK''' button in the dialog-box '''(Remove Layers or Groups)'''
|| From the '''context menu''', click on '''Remove''' option.


A '''prompt''' appears to confirm the action.

Click on '''OK''' button.

|-
|| 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

* 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.

|-
|| '''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.

|-
|| 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.



|-
|| '''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:'''


Do you have questions in THIS Spoken Tutorial?

•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



|| 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

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