QGIS/C2/Digitizing-Map-Data/English-timed
From Script | Spoken-Tutorial
Time | Narration |
00:01 | Welcome to this tutorial on Digitizing Map Data in QGIS. |
00:07 | In this tutorial, we will learn to- Create and digitize Point and Polygon shape files. |
00:15 | Change style and color for Point and Polygon features. |
00:20 | To record this tutorial I am using-
Ubuntu Linux OS version 16.04 QGIS version 2.18 |
00:32 | To follow this tutorial, you should be familiar with basic GIS and QGIS interface. |
00:41 | Digitizing is the process by which, coordinates from a map, image or other sources of data
are converted into a digital format. |
00:52 | The converted data can be stored as a point, line or a polygon feature in GIS. |
01:00 | To practise this tutorial, you need to download the thematic map of Bangalore city given in the Code files link. |
01:09 | This is a map depicting development of Bangalore city. |
01:15 | Steps to download the code files. |
01:18 | Click on the link Code files, located below the player and save it in your folder. |
01:25 | Extract the downloaded zip file. |
01:28 | Locate Bangalore.jpg file in the extracted folder. |
01:34 | I have already downloaded the Code file, extracted and saved in a folder on Desktop. |
01:41 | Double-click on the folder to open it. |
01:45 | Right-click on Bangalore.jpg file. |
01:49 | From the context menu select, Open with QGIS Desktop. |
01:56 | QGIS interface opens. |
01:59 | QGIS Tips dialog-box opens. Click on OK button. |
02:06 | Coordinate Reference System Selector dialog-box opens. |
02:11 | Under the heading, Coordinate reference systems of the world, Select WGS 84. |
02:19 | Note that WGS 84 is the most widely used geographic coordinate system. |
02:27 | Click on OK button at the bottom of the dialog-box. |
02:32 | Thematic map of Bangalore is displayed on the canvas. |
02:38 | Now let us create new shape file layers. |
02:42 | Click on Layer menu on the menu bar and select Create Layer option. |
02:50 | From the sub-menu, select New Shapefile Layer option. |
02:55 | New Shapefile Layer window opens. |
02:59 | Here you can see options for 3 types of features, Point, Line and Polygon. |
03:10 | By default Point option is selected.
Leave it as such. |
03:16 | Let the CRS be WGS 84. |
03:21 | Click on OK button at the bottom-right corner of the window. |
03:27 | Save Layer as.. dialog-box opens. |
03:31 | Let us name the file as Point-1. |
03:35 | Select a suitable location to save the file.
I will choose Desktop. |
03:42 | Click on Save button at the bottom-right corner of the dialog-box. |
03:48 | Files will be saved on the desktop as shown here. |
03:53 | Back to the QGIS interface. |
03:56 | Notice that the file will be automatically loaded in the Layers Panel. |
04:02 | On this map, we will mark the locations where IT departments are established. |
04;09 | Scroll the center mouse button to zoom-in. |
04:14 | Refer to the legend at the bottom-right corner of the map for IT establishments. |
04:21 | IT establishments are indicated as flag symbol. |
04:26 | Locate the points indicating IT establishments on the map. |
04:32 | There are two points indicating IT establishments. |
04:37 | To edit or modify features on the map, we need to select the Toggle editing tool. |
04:44 | Toggle Editing tool is available on the top-left corner of the tool bar. |
04:51 | Click on the Toggle Editing tool to select it. |
04:55 | Click on Add Feature tool on the tool bar. |
04:59 | The cursor is now displayed as a crosshair icon. |
05:04 | Click on IT establishment symbol on the map. |
05:08 | An input-box Point-1 Feature Attributes opens. |
05:14 | Type 1 in the id text box. Click on OK button. |
05:21 | Similarly click on the second IT establishment and save the feature as 2.
Click on OK button. |
05:31 | Now to stop editing, again click on Toggle Editing tool on the tool bar. |
05:38 | Stop editing dialog-box opens. |
05:42 | Click on Save button. |
05:45 | Observe, on the map, two colored point features are created. |
05:51 | We can check the two features created, by opening the attribute table. |
05:56 | Right-click on the Point-1 layer on the Layers panel. |
06:01 | From the context menu, select Open Attribute Table option. |
06:06 | In the Point-1: Features dialog-box, in id column, two points are created. |
06:13 | Close the attribute table dialog-box. |
06:17 | Style and color of these point features can be changed for clear visibility. |
06:23 | Right-click on the Point-1 layer. |
06:26 | From the context menu choose Properties option. |
06:31 | Layer Properties dialog-box opens. |
06:35 | Click on the Color drop down. |
06:38 | Choose a color by rotating the color triangle. |
06:42 | Increase the size by clicking on upward arrow triangle at the end of Size text box. |
06:50 | Click on OK button at the bottom of the dialog-box. |
06:54 | Notice the change in color and size for the Point features. |
07:00 | Now let us create a shape file containing Polygon features. |
07:05 | Click on Layer menu on the menu bar. Select Create Layer option. |
07:12 | From the sub-menu, select New Shapefile Layer. |
07:17 | New Shape File Layer window opens. |
07:21 | Select Type as Polygon. |
07:25 | In the New field Name text box, type area. |
07:31 | Let the Type be Text data. |
07:35 | Click on Add to fields list button |
07:40 | In the Fields List table, you will see area row added.
Click on OK button. |
07:50 | Save layer as.. dialog-box opens. |
07:54 | Type the File name as Area-1. |
07:58 | Select a suitable location. |
08:01 | I will select Desktop. Click on Save button. |
08:07 | Notice that Area-1 layer is added to the Layers panel. |
08:13 | We will mark the boundary of Corporation Area and Greater Bangalore area. |
08:20 | Refer to the Legend on the map to locate Corporation area and Greater Bangalore area. |
08:28 | Turn on the toggle editing by clicking on Toggle Editing tool on the tool bar. |
08:35 | Click on Add Feature tool from the tool bar. |
08:39 | Bring the cursor to the map. |
08:42 | To mark the area, click anywhere on the boundary of Corporation area. |
08:48 | Keep clicking on the boundary. |
08:51 | Warning messages may appear at the top of the canvas if the line segments intersect.
Please ignore these messages. |
09:02 | If you make a mistake and want to restart the marking process, press Esc Key on the keyboard. |
09:10 | You can start the process again. |
09:13 | Keep clicking on the boundary till you span the entire boundary. |
09:24 | Once you have marked the entire boundary, right-click to end the polygon. |
09:30 | Area-1- Feature Attributes input box opens. |
09:36 | Type 1 in the id text box. |
09:40 | Type Corporation Area in area text box. |
09:45 | Click on OK button. |
09:48 | Observe, on the map new polygon feature is created. |
09:54 | Now we will digitize Greater Bangalore region in the map. |
09:59 | Click on the boundary to digitize Greater Bangalore region as shown here. |
10:12 | After you finish digitizing, right-click to end the polygon. |
10:18 | In the Area-1 Feature Attributes text box, type 2 in the id text box.
And Greater Bangalore in the area text box. |
10:30 | Click on OK button. |
10:33 | Again click on Toggle Editing tool in the tool bar to stop editing. |
10:39 | Click on Save button in the Stop editing dialog box. |
10:44 | Right click on Area-1 layer to open attribute table. |
10:49 | Select Open Attribute Table from the context menu. |
10:54 | We can see that 2 features have been created with columns id and area type.
Close the attribute table. |
11:04 | We can see that two polygon features have been created. |
11:09 | To change the color and style of polygon feature, right click on Area-1 layer.
Select Properties option. |
11:19 | In the Layer Properties dialog-box, select Style option from the left panel. |
11:26 | On the top left corner of the drop down menu, select categorized. |
11:32 | In the column drop down select id.
Click on Classify button. |
11:39 | Move the Layer transparency slider to 50 %. |
11:44 | Click on OK button at the bottom of the dialog-box. |
11:49 | Now on the map, we can see that the two Polygon features are in different color. |
11:55 | Details about labeling the features, will be discussed in upcoming tutorials in the series. |
12:03 | Let's summarize. |
12:05 | In this tutorial we have learnt to, Create and digitize Point and Polygon shape files. |
12:13 | Change style and color for Point and Polygon features. |
12:18 | As an Assignment, On the Banglaore thematic map (Bangalore.jpg),
Digitize Industrial Estates Digitize the roads on the map, by creating a Polyline feature. |
12:32 | Your completed assignment should look as shown here. |
12:37 | The video at the following link summarises the spoken tutorial project. Please download and watch it. |
12:45 | The spoken tutorial project team conducts workshops and gives certificates on passing online tests
For more details please write to us. |
12:57 | Please post your timed queries on this forum. |
13:01 | The Spoken Tutorial Project is funded by NMEICT, MHRD Government of India.
More information on this mission is available at the following link. |
13:13 | This tutorial is contributed by Prajwal.M from Sahyadri college of Engineering and Snehalatha from IIT Bombay.
Thank you for joining. |