QGIS/C3/Table-Joins-and-Spatial-Joins/English-timed
From Script | Spoken-Tutorial
| Time | Narration |
| 00:01 | Welcome to this tutorial on Table Joins and Spatial Joins in QGIS. |
| 00:08 | In this tutorial, we will learn to join the attribute tables of two data-sets having,
common field , and same spatial data |
| 00:19 | Here I am using
Ubuntu Linux OS version. 16.04 |
| 00:26 | QGIS version 2.18 |
| 00:30 | To follow this tutorial learner should be familiar with QGIS interface. |
| 00:36 | For the prerequisite QGIS tutorials, please visit this website. |
| 00:42 | Download the folder given in the Code files link, located below the player. |
| 00:48 | Extract the contents of the downloaded zip file and save it in a folder. |
| 00:54 | I have already downloaded the Code files, extracted and saved in a folder on the Desktop. |
| 01:01 | Double-click on the folder to open it. |
| 01:04 | Locate Stations.shp file in the extracted folder. |
| 01:09 | The Stations.shp file shows locations of meteorological stations or air stations across India. |
| 01:17 | Here we also have other files required to practice this tutorial. |
| 01:23 | Joining the attribute tables means, combining the attribute data between two data-sets. |
| 01:30 | There are two ways to join a table,
Table Join that is, joining tables having one or more common column data. |
| 01:40 | Spatial Join means joining tables having same spatial data. |
| 01:46 | In this tutorial we will be demonstrating both the methods. |
| 01:50 | For more information please visit this website. |
| 01:54 | Open QGIS interface. |
| 01:57 | First, we will join attribute tables having common field. |
| 02:02 | Click on Add Vector Layer tool from the toolbar on the left-side. |
| 02:07 | Add Vector Layer dialog box opens. |
| 02:10 | Click on Browse button next to Dataset field.
A dialog-box opens. |
| 02:17 | Navigate to Stations.shp file from the Code files folder on the Desktop. |
| 02:22 | Click on Open button. |
| 02:25 | In the Add vector layer dialog box, click on Open button. |
| 02:30 | The Stations.shp layer will be added in the Layers Panel. |
| 02:35 | The corresponding map appears on the canvas. |
| 02:39 | This map shows point features, corresponding to meteorological stations located in different states in India. |
| 02:47 | Let us open the attribute table for this layer. |
| 02:51 | In the Layers Panel, right-click on Stations.shp. |
| 02:56 | From the context menu choose Open Attribute Table option. |
| 03:01 | Attribute table opens. |
| 03:03 | Notice that data for only one attribute District is available. |
| 03:10 | Minimize the attribute table. |
| 03:13 | Now we will add another data-set which is a spreadsheet to the Layers Panel.
This data set is in CSV format. |
| 03:23 | Click on Layer menu on the menu bar.
Click on Add layer. |
| 03:30 | From the sub-menu click on Add Delimited Text Layer option. |
| 03:35 | A dialog box opens. |
| 03:38 | Click on Browse button located next to File Name field. |
| 03:43 | A dialog box opens. |
| 03:46 | Navigate to Rainfall.csv file from the Code files folder on the Desktop.
Click on Open button. |
| 03:54 | In the Delimited Text File dialog box, select CSV as File Format. |
| 04:01 | Select Geometry definition as No geometry.
Leave all other fields as such. |
| 04:09 | Click on OK button. |
| 04:12 | On QGIS canvas, Rainfall layer will be added in the Layers Panel. |
| 04:18 | Right-click on Rainfall layer. |
| 04:21 | Click on the Open Attribute Table from the context menu. |
| 04:26 | Attribute table opens.
The attribute table has rainfall data from January to December for various districts. |
| 04:37 | Maximize the Stations attribute table and compare both the tables. |
| 04:43 | Please note, the District field is common in both Rainfall and Stations layers. |
| 04:50 | Now we will add the attribute data from Rainfall layer to Stations layer. |
| 04:56 | In the Stations attribute table there is only one column named District. |
| 05:02 | We will add the Rainfall data to the Stations attribute table. |
| 05:07 | Close the attribute tables. |
| 05:10 | Select Stations layer in the Layers Panel. |
| 05:14 | This layer will receive the new data from the Rainfall layer. |
| 05:19 | Right-click on Stations layer. |
| 05:22 | Click on the Properties option from the context menu. |
| 05:26 | Layer Properties dialog box opens.
Click on Joins from the left panel. |
| 05:33 | In the new window, click on the plus sign, located on the bottom-left corner. |
| 05:39 | Add vector join dialog box opens. |
| 05:43 | Here we have options to choose for Join layer, Join field and Target field. |
| 05:51 | Join layer will be Rainfall layer, from which data will be added to Stations attribute table. |
| 05:59 | Here Rainfall layer is already selected. |
| 06:03 | Join field is the field or attribute in the Rainfall table to be joined. |
| 06:10 | In the Join field, select District from the drop-down. |
| 06:15 | Target field is the field to be joined in the Stations table. |
| 06:20 | In the Target field, District is already selected. |
| 06:25 | This field is common to both the tables. |
| 06:29 | Check the check-box for Choose which fields are joined. |
| 06:34 | The text-box below is now populated with all the columns and check-boxes. |
| 06:41 | Check the boxes for the columns January to Annual Average in the text box. |
| 06:48 | Click on OK button to close the Add vector join dialog box. |
| 06:53 | In Layer Properties dialog box, information about layer and columns joined are indicated at the top. |
| 07:02 | Click on Apply button, then OK button. |
| 07:06 | On the QGIS interface, as shown earlier open attribute table for Stations layer. |
| 07:14 | Observe that this table shows Rainfall data for all the stations. |
| 07:20 | Close attribute table. |
| 07:23 | Next, we will learn how to join attribute table of two data-sets by location. |
| 07:30 | Let us add another layer to the Layers Panel. |
| 07:34 | For this click on Add Vector Layer tool. |
| 07:38 | In the Add Vector Layer dialog box, click on Browse button. |
| 07:43 | Navigate to the Admin.shp from the Code files folder on the Desktop. |
| 07:49 | Click on Open button. |
| 07:51 | Again click on Open button in the Add Vector Layer dialog box. |
| 07:56 | Admin layer is now added to the Layers Panel. |
| 08:00 | Admin layer map opens showing the administrative state boundaries of India. |
| 08:07 | Click the Admin layer in the Layers panel. |
| 08:11 | Drag and bring it below Stations layer. |
| 08:15 | Now we can view the point features located in different States. |
| 08:20 | Open attribute table for Admin layer. |
| 08:24 | The attribute table shows information related to states. |
| 08:29 | Minimize the Admin attribute table.
Again open the Stations attribute table. |
| 08:36 | Now we will join the attributes by location for Stations layer and Admin layer. |
| 08:43 | Close both the attribute tables. |
| 08:47 | Click on Vector menu. |
| 08:48 | Scroll down the menu and click on Data Management Tools. |
| 08:53 | From the sub-menu select Join attributes by location. |
| 08:58 | Join attributes by location dialog box opens. |
| 09:02 | Click on the drop-down for Target vector layer. |
| 09:05 | Here we need to specify the target vector layer for joining the attribute table. |
| 09:12 | In our case we need to add new data to the Stations layer. |
| 09:17 | Hence Stations layer is the Target Layer. |
| 09:21 | So we will select Stations [EPSG: 4326] from the drop-down as target layer. |
| 09:29 | Click on the drop-down for Join vector layer. |
| 09:33 | Here we have to select the layer which we want to join with the target layer. |
| 09:40 | Select Admin [EPSG: 4326] from the drop-down. |
| 09:45 | Here we have several options for joining the attributes. |
| 09:50 | We are interested to find the meteorological stations located in various states. |
| 09:56 | So under Geometric predicate, we will select within check-box.
Scroll down. |
| 10:04 | Check the check-box for Open output file after running algorithm. |
| 10:10 | Leave the rest of the settings as default.
Click on the Run button. |
| 10:17 | Status bar at the bottom shows the progress of the processing algorithm.
Wait for the process to complete. |
| 10:25 | On the canvas, a new layer, Joined layer is added in the Layers Panel. |
| 10:32 | Right-click on the Joined layer and open attribute table. |
| 10:37 | This table contains all the attributes from Admin layer for each point on the Stations layer. |
| 10:45 | Every point feature has information about the state. |
| 10:49 | Close the attribute table. |
| 10:52 | To save the project, click on Project menu from the menu bar.
Select Save As option. |
| 11:01 | Give an appropriate name and select a convenient location. |
| 11:06 | Click on Save button. |
| 11:10 | Let us summarize. |
| 11:12 | In this tutorial we have learnt to join the attribute tables of two data-sets having,
common field, and same spatial data |
| 11:22 | As an assignment,
Join the rainfall data from June to December with the stations data. |
| 11:30 | Use Rainfall.csv and Stations.shp files given in the Code files folder. |
| 11:37 | The completed assignment should look like this. |
| 11:41 | This video summarizes the Spoken Tutorial project.
Please download and watch it. |
| 11:48 | The spoken tutorial project team conducts workshops and gives certificates.
For more information please write to us. |
| 11:58 | Please post your timed queries on this forum. |
| 12:02 | The Spoken Tutorial Project is funded by NMEICT, MHRD Government of India. |
| 12:10 | This tutorial is contributed by Ambadas Maske from College of Engineering Pune, Snehalatha Kaliappan and Himanshi Karwanje from IIT Bombay.
Thank you for joining. |
