Difference between revisions of "QGIS/C2/Digitizing-Map-Data/English"
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− | + | To practise this tutorial, you need to download the thematic map of '''Bangalore''' city given in the '''Code files''' link. | |
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Revision as of 17:15, 23 October 2018
Visual Cue | Narration |
Slide Number 1
Title Slide |
Welcome to this tutorial on Digitizing Map Data in QGIS. |
Slide Number 2
Learning Objectives |
In this tutorial, we will learn to-
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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 |
To follow this tutorial, you should be familiar with basic GIS and QGIS interface. |
Slide Number 5
Digitizing
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Digitizing is the process by which,
coordinates from a map, image or other sources of data are converted into a digital format.
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Slide Number 6
Example map to practise
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To practise this tutorial, you need to download the thematic map of Bangalore city given in the Code files link.
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Slide Number 7
Steps to download Code files |
Steps to download the code files.
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Show the map Bangalore.jpg on desktop. | I have already downloaded the Code file, extracted and saved in a folder on Desktop. |
Double-click on the folder. | Double-click on the folder to open it. |
Right-click on Bangalore.jpg file.
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Right-click on Bangalore.jpg file.
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Cursor on QGIS interface.
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QGIS interface opens.
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Cursor on Coordinate Reference System Selector dialog-box | Coordinate Reference System Selector dialog-box opens. |
Click on WGS 84, under the heading, Coordinate reference systems of the world.
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Under the heading, Coordinate reference systems of the world, Select WGS 84.
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Cursor on canvas. | Thematic map of Bangalore is displayed on the canvas. |
Now let us create new shape file layers. | |
Click on Layer menu.
Select Create Layer option. Click on New Shapefile Layer option. |
Click on Layer menu on the menu bar and select Create Layer option.
From the sub-menu, click on New Shapefile Layer option. |
Cursor on New Shapefile Layer dialog box. | New Shapefile Layer window opens. |
Point to the 3 options | Here you can see options for 3 types of features, Point, Line and Polygon. |
Point to Point option | By default Point option is selected.
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Point to CRS | In the CRS, let the CRS be WGS 84. |
Click on OK button. | Click on OK button at the bottom-right corner of the window. |
Type Point-1 in the name field in Save Layer as.. dialog-box .
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Save Layer as.. dialog-box opens.
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Select Desktop.
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Select a suitable location to save the file.
I will choose Desktop.
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Show the desktop which has all the saved files. | Files will be saved on the desktop as shown here. |
Point towards the Point-1 layer on Layers panel. | Back to the QGIS interface.
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Cursor on the map. | On this map, we will mark the locations where IT departments are established. |
Scroll the centre mouse button. | Scroll the center mouse button to zoom-in. |
Cursor on the points.
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Refer to the legend at the bottom-right corner of the map for IT establishments.
Locate the points indicating IT establishments on the map. |
Click on the symbols for IT establishments as indicated on legend. | There are two points indicating IT establishments. |
To edit or modify features on the map, we need to select the Toggle editing tool. | |
Point to the Toggle Editing. | Toggle Editing tool is available on the top-left corner of the tool bar. |
Click on the Toggle Editing tool on tool bar. | Click on the Toggle Editing tool to select it. |
Select Add Feature option. | Click on Add Feature tool on the tool bar. |
High-light the cursor (editing) | The cursor is now displayed as a crosshair icon. |
Click on flag symbol. | Click on IT establishment symbol on the map. |
Type I in the text box in Point-1 Feature Attribute input box.
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An input-box Point-1 Feature Attributes opens.
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Click on another symbol for IT establishment.
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Similarly click on the second IT establishment and save the feature as 2.
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Click on Toggle Editing tool on the tool bar. | Now to stop editing, again click on Toggle Editing tool on the tool bar. |
click on Save button in Stop editing dialog-box. | Stop editing dialog-box opens.
Click on Save button. |
Point towards two colored dots on the map. | Observe, on the map, two colored point features are created. |
We can check the two features created, by opening the attribute table. | |
Right-click on the Point-1 layer on the Layers panel.
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Right-click on the Point-1 layer on the Layers panel.
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Point towards the created features. | In the Point1: Features dialog-box, in id column, two points are created. |
Click on x symbol at the top-left corner of the attribute table. | Close the attribute table dialog-box. |
Cursor on the canvas. | Style and color of these point features can be changed for clear visibility. |
Right-click on Point-1 layer. | Right-click on the Point-1 layer. |
From the context menu choose Properties option. | From the context menu choose Properties option. |
Cursor on Layer Properties dialog-box. | Layer Properties dialog-box opens. |
Click on the Color drop down.
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Click on the Color drop down.
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Click the upward arrow triangle at the end of the Size text box. | Increase the size by clicking on upward arrow triangle at the end of Size text box. |
Click on OK button at the bottom of the window. | Click on OK button at the bottom of the dialog-box. |
Cursor on Point features. | Notice the change in color and size for the Point features. |
Now let us create a shape file containing Polygon features. | |
Click on Layer menu on the menu bar.
Select Create Layer option. |
Click on Layer menu on the menu bar.
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Click on New Shapefile Layer option. | From the sub-menu, select New Shapefile Layer. |
In the New Shapefile Layer dialog box,
Click on Polygon radio button |
New Shape File Layer window opens.
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In New field Name type area. | In the New field Name text box, type area.
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Click on Add to fields list button.
Click on OK button. |
Click on Add to fields list button
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Type the File name as Area-1 in
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Save layer as.. dialog-box opens.
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Select Desktop.
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Select a suitable location.
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Point to the Layer Panel and
Area-1 layer. |
Notice that Area-1 layer is added to the Layers panel. |
We will mark the boundary of Corporation Area and Greater Bangalore area. | |
Point to the Legend on the map. | Refer to the Legend on the map to locate Corporation area and Greater Bangalore area. |
Click on Toggle Editing tool on the tool bar. | Turn on the toggle editing by clicking on Toggle Editing tool on the tool bar. |
Click on Add Feature tool from the tool bar. (The tool is 4th tool from left on the 2nd row on tool bar)
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Click on Add Feature tool from the tool bar. |
Bring the cursor to the map.
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Bring the cursor to the map.
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Click on the boundary of corporation area. | Keep clicking on the boundary. |
Point to the warning messages. | Warning messages may appear at the top of the canvas if the line segments intersect.
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Press Esc Key on the keyboard. | If you make a mistake and want to restart the marking process, press Esc Key on the keyboard.
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Click on the entire boundary. | Keep clicking on the boundary till you span the entire boundary. |
Right click to end the polygon. | Once you have marked the entire boundary, right-click to end the polygon. |
In Area-1- Feature Attributes input box,
Type 1 in ID text box.
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Area-1- Feature Attributes input box opens.
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Click on OK button. | Click on OK button. |
Point to the polygon feature. | Observe, on the map new polygon feature is created. |
Now we will digitize Greater Bangalore region in the map. | |
Click on the boundary of Greater Bangalore region. | Click on the boundary to digitize Greater Bangalore region as shown here. |
Right-click to end the polygon. | After you finish digitizing, right-click to end the polygon. |
In the Area-1 Feature Attributes text box,
Type 2 in the id text box. Type Greater Bangalore in the area text box. |
In the Area-1 Feature Attributes text box, type 2 in the id text box.
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Click on OK button. | Click on OK button. |
Click on Toggle Editing tool in the tool bar. | Again click on Toggle Editing tool in the tool bar to stop editing. |
Click on Save button in the Stop editing dialog box. | Click on Save button in the Stop editing dialog box. |
Right click on Area-1 layer in the layers panel.
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Right click on Area-1 layer to open attribute table.
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Click on x on the top-left corner of the attribute table. | We can see that 2 features have been created with columns id and area type.
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Point to polygon features on the map. | We can see that two polygon features have been created. |
Right click Area-1
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To change the color and style of polygon feature, right click on Area-1 layer.
Select Properties option. |
In the Layer Properties dialog-box, click on style option. | In the Layer Properties dialog-box, select Style option from the left panel. |
Select categorized option from top left corner of the drop down menu. | On the top left corner of the drop down menu, select categorized. |
In the column drop down select id.
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In the column drop down select id.
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Drag the transparency slider to 50 %. | Move the Layer transparency slider to 50 %. |
Click Ok button. | Click on OK button at the bottom of the dialog-box. |
Point to two polygon features on the map. | Now on the map, we can see that the two Polygon features are in different color. |
Details about labeling the features, will be discussed in upcoming tutorials in the series. | |
Let's summarize. | |
Slide Number 8
Summary |
In this tutorial we have learnt to,
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Slide Number 9
Assignment |
As an Assignment,
On the Banglaore thematic map (Bangalore.jpg),
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Your completed assignment should look as shown here. | |
Slide Number 10
About the Spoken Tutorial Project |
The video at the following link summarises the spoken tutorial project.
Please download and watch it. |
Slide Number 11
Spoken Tutorial Workshops |
The spoken tutorial project team conducts workshops and gives certificates on passing online tests
For more details please write to us. |
Slide number 12
Forum for specific questions: |
Please post your timed queries on this forum. |
Slide number 13
Acknowledgements |
The Spoken Tutorial Project is funded by NMEICT, MHRD Government of India.
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Slide number 13
Acknowledgements |
This tutorial is contributed by Prajwal.M from Sahyadri college of Engineering and Snehalatha from IIT Bombay.
Thank you for joining. |