Editing Vector Data in GRASS GIS - Revision history

SheaTimmins at 18:23, 22 December 2022

2022-12-22T18:23:34Z

SheaTimmins at 19:10, 21 December 2022

2022-12-21T19:10:08Z

SheaTimmins at 19:08, 21 December 2022

2022-12-21T19:08:28Z

SheaTimmins at 18:59, 21 December 2022

2022-12-21T18:59:53Z

SheaTimmins at 18:57, 21 December 2022

2022-12-21T18:57:17Z

SheaTimmins at 18:55, 21 December 2022

2022-12-21T18:55:52Z

SheaTimmins at 18:40, 21 December 2022

2022-12-21T18:40:01Z

SheaTimmins at 18:38, 21 December 2022

2022-12-21T18:38:14Z

SheaTimmins at 18:27, 21 December 2022

2022-12-21T18:27:16Z

SheaTimmins at 18:20, 21 December 2022

2022-12-21T18:20:26Z

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 ===Displaying Layers Based on Attribute Data===
-The first thing we will edit in our Map display is the Red_Light_Camera_Violations_2019.shp data. We are going to display only the intersections that have 700 or more traffic violations in the year of 2019.
+The first thing we will edit in our Map display is the Red_Light_Camera_Violations_2019.shp data. We are going to display only the intersections that have 500 or more traffic violations in the year of 2019.
 Right-click on Red_Light_Camera_Violations_2019.shp and select "Properties."

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-Next we are going to edit the symbol size and shape. Right-click on the Traffic_Collision_by_Location_2019 layer. Select “Properties,” then select the “Symbols” tab. Click on the “X” to change the shape of the symbol. Select the circle as the new symbol. Next change the symbol size to 6. Your “Symbols tab should look like the photo below.
+Next we are going to edit the symbol size and shape. Right-click on the Traffic_Collision_by_Location_2019 layer. Select “Properties,” then select the “Symbols” tab. Click on the “X” to change the shape of the symbol. Select the circle as the new symbol. Next change the symbol size to 6. Your “Symbols" tab should look like the photo below.
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+==Conclusion==
+In this tutorial, you have begun to explore ways of editing your map display in GRASS GIS. By the end of it, you should be more comfortable uploading data into GRASS, and editing symbols in vector layers. There is much more you can do in this program, and hopefully this tutorial gives you the confidence and the basics to continue to explore the features of GRASS.

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 Before you press “Apply” and close this window, navigate back to the “Colors” tab and change the “Area fill color” to yellow. Then press apply. The Map Display should now look like the one below.
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+<br />
 [[File:symbolstuff.png|500px]]
+<br />
+<br />
+Now we will do the same thing for the Red_Light_Camera_Violations_2019 layer. Right-click on this layer, and select “Properties.” Then, go to the “Symbols” tab and change the symbol from “X” to a circle, and the size from 5 to 6. Before you press “Apply,” navigate to the “Colors” tab and select the color red for the “Area fill color.” You Map Display should now look like the one below.
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+<br />
+[[File:peachtea.png|500px]]
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 Before you press “Apply” and close this window, navigate back to the “Colors” tab and change the “Area fill color” to yellow. Then press apply. The Map Display should now look like the one below.
-[[symbolstuff.png|500px]]
+[[File:symbolstuff.png|500px]]
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-[[File:yeehaw.png|400px]]
+[[File:yeehawz.png|500px]]
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 [[File:displayz.png|500px]]
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+Our data is concentrated in the downtown area of Ottawa, so we are going to zoom in this area to make our Display more readable. Select the magnifying glass at the top of your screen that has the plus sign. Then click the center of the most concentrated area of your map. The result on your map display should be similar to the one below.
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+[[File:yeehaw.png|400px]]
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-Next, navigate back to the Layers Manager window in GRASS. Ensure that you are working in the correct location by right clicking ottawa_roads_safety and selecting "switch mapsets." Next Select the icon shaped like a "V" to import vector data.
+Next, navigate back to the Layers Manager window in GRASS. Ensure that you are working in the correct location by right-clicking ottawa_roads_safety and selecting "switch mapsets." Next Select the icon shaped like a "V" to import vector data.
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 == Editing the Map Display ==
-First make sure the layers are in the correct order. Roads_Centrelines.shp should be the bottom layer. If this is not the case, simply click and drag that layer to the beneath the other two. We are then going to edit our Map Display so that it displays the intersections and areas in Ottawa with a significant number of red light traffic violations and traffic violations in one year.
+First, make sure the layers are in the correct order. Roads_Centrelines.shp should be the bottom layer. If this is not the case, simply click and drag that layer to the beneath the other two. We are then going to edit our Map Display so that it displays the intersections and areas in Ottawa with a significant number of red light traffic violations and traffic violations in one year.
 ===Displaying Layers Based on Attribute Data===
 The first thing we will edit in our Map display is the Red_Light_Camera_Violations_2019.shp data. We are going to display only the intersections that have 700 or more traffic violations in the year of 2019.
-Right click on Red_Light_Camera_Violations_2019.shp and select "Properties."
+Right-click on Red_Light_Camera_Violations_2019.shp and select "Properties."
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-Now we will repeat these steps with the Traffic_Collision_by_Location_2019 layer. Right click on this layer, and select "Properties." Next, select the "Selection" tab. Select the same square icon again underneath (where=sql_query). This time, double click the Total_Coll column. Then select the >= button, and type 10. Select "Apply." Select "Apply" again then close the d.vect window. We have now set the Map Display to only display areas with 10 collisions or more in the year 2019.
+Now we will repeat these steps with the Traffic_Collision_by_Location_2019 layer. Right-click on this layer, and select "Properties." Next, select the "Selection" tab. Select the same square icon again underneath (where=sql_query). This time, double-click the Total_Coll column. Then select the >= button, and type 10. Select "Apply." Select "Apply" again then close the d.vect window. We have now set the Map Display to only display areas with 10 collisions or more in the year 2019.
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 [[File:collisions10.png|400px]]
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+<br />
+===Editing Symbols===
+We will start by editing the Traffic_Collision_by_Location_2019 symbols on our Map Display. By default, they are the same color as the other layers, making the information very difficult to discern. We will start by changing the color of the symbol. Right-click on the Traffic_Collision_by_Location_2019 layer, and select “Properties.” Then select the “Colors” tab. It should look like the photo below.
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+[[File:colorz.png|400px]]
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+Click on the “Feature color.” Then select a new color, in the example below a bright green was selected. Click “OK” and then “Apply.” There is an example of what your Map Display should look like below.
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+<br />
+[[File:colorzz.png|400px]]
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+<br />
+[[File:mapz.png|400px]]
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+Now we will repeat these steps with the Red_Light_Camera_Violations_2019 layer. Right-click on this layer, and select “Properties.” Navigate to the “Colors” tab, and select a red color. Click “OK” and then “Apply.” Now your Map Display should look like the one below.
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+<br />
+[[File:displayz.png|500px]]
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