Path Analysis with Vector Data Using QGIS - Revision history

Smitch: /* Data */

2020-10-19T16:16:52Z

Data

Smitch: /* Introduction */

2020-10-19T16:11:31Z

Introduction

Misztal: /* Shortest Path Analysis */

2020-10-06T23:42:26Z

Shortest Path Analysis

Misztal: /* Shortest Path Analysis */

2020-10-06T18:28:07Z

Shortest Path Analysis

Misztal: /* Shortest Path Analysis */

2020-10-06T18:27:44Z

Shortest Path Analysis

Misztal: /* Shortest Path Analysis */

2020-10-06T17:12:44Z

Shortest Path Analysis

Misztal: /* Shortest Path Analysis */

2020-10-06T17:08:48Z

Shortest Path Analysis

Misztal: /* Shortest Path Analysis */

2020-10-06T17:05:33Z

Shortest Path Analysis

Misztal: /* Shortest Path Analysis */

2020-10-06T16:32:01Z

Shortest Path Analysis

Misztal: /* Shortest Path Analysis */

2020-10-06T16:30:44Z

Shortest Path Analysis

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 == '''Data''' ==
-The type of data that we will be using are Keyhole Markup Language (KML) and shapefiles. We will be using vector data for this analysis (spatial data which represents features using points, lines, or polygons). KML is a file format that is used to display geographic data. It is an international standard that is maintained by the Open Geospatial Consortium, Inc. (OGC). A shapefile is a data format used by GIS software to display geospatial vector datasets and consists of three or more files.
+The type of data that we will be using are Keyhole Markup Language (KML) and shapefiles. We will be using vector data for this analysis (spatial data which represents features using points, lines, or polygons). KML is a file format that is used to hold geographic data. It is an international standard that is maintained by the Open Geospatial Consortium, Inc. (OGC). A shapefile is another data format used by GIS software to hold geospatial vector data and despite the name, it actually consists of three or more files, all with the same prefix filename but different extensions (.shp, .shx, .dbf, ...).
 The data that will be used for this tutorial can be found from the following links:

← Older revision		Revision as of 16:11, 19 October 2020
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	== '''Introduction''' ==		== '''Introduction''' ==

	QGIS is an application that is used for GIS (Geographic Information Systems) purposes that is Free and Open Source Software (FOSS). This software is user friendly. It runs on Linux, Unix, Windows, Mac OSX and Android. QGIS supports a variety of raster, vector and database formats and functions. It provides a ~~continuous~~ growing number of capabilities~~. It is~~ provided by core functions and plugins. With QGIS, the user can manage, edit, conduct data analysis, visualize and create maps.		QGIS is an application that is used for GIS (Geographic Information Systems) purposes that is Free and Open Source Software (FOSS). This software is user friendly. It runs on Linux, Unix, Windows, Mac OSX and Android. QGIS supports a variety of raster, vector and database formats and functions. It provides a continuously growing number of capabilities, provided by core functions and plugins. With QGIS, the user can manage, edit, conduct data analysis, visualize and create maps.

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 '''Figure 18.''' The start and cost columns in the attribute table of the Shortest path layer.
+This analysis can be completed using any of the other path network and intersection layers as well.
 == '''References''' ==

← Older revision		Revision as of 18:28, 6 October 2020
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	Using the intersections layers created in the [[Path_Analysis_with_Vector_Data_Using_QGIS#Process\|Process]] section, we will now use a Network Analysis tool within QGIS to calculate the shortest path between any random point in Ottawa and the intersection points of The Rideau Trail. Say you wanted to access The Rideau Trail from Carleton Universtiy, but you only wanted to travel along the roads to get to it. In this scenario, we will be using the Roads_Centrelines layer and the Roads_Centreline_Intersections points that were previously created to find the shortest distances possible to each of the places where a road and The Rideau Trail intersect. This analysis aims to answer the question, how do I get to the Rideau Trail using roads from my location in Ottawa?		Using the intersections layers created in the [[Path_Analysis_with_Vector_Data_Using_QGIS#Process\|Process]] section, we will now use a Network Analysis tool within QGIS to calculate the shortest path between any random point in Ottawa and the intersection points of The Rideau Trail. Say you wanted to access The Rideau Trail from Carleton Universtiy, but you only wanted to travel along the roads to get to it. In this scenario, we will be using the Roads_Centrelines layer and the Roads_Centreline_Intersections points that were previously created to find the shortest distances possible to each of the places where a road and The Rideau Trail intersect. This analysis aims to answer the question, how do I get to the Rideau Trail using roads from my location in Ottawa?

	NOTE: This analysis was conducted using QGIS v3.4		NOTE: This analysis was conducted using QGIS 3.4.

← Older revision		Revision as of 18:27, 6 October 2020
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	Using the intersections layers created in the [[Path_Analysis_with_Vector_Data_Using_QGIS#Process\|Process]] section, we will now use a Network Analysis tool within QGIS to calculate the shortest path between any random point in Ottawa and the intersection points of The Rideau Trail. Say you wanted to access The Rideau Trail from Carleton Universtiy, but you only wanted to travel along the roads to get to it. In this scenario, we will be using the Roads_Centrelines layer and the Roads_Centreline_Intersections points that were previously created to find the shortest distances possible to each of the places where a road and The Rideau Trail intersect. This analysis aims to answer the question, how do I get to the Rideau Trail using roads from my location in Ottawa?		Using the intersections layers created in the [[Path_Analysis_with_Vector_Data_Using_QGIS#Process\|Process]] section, we will now use a Network Analysis tool within QGIS to calculate the shortest path between any random point in Ottawa and the intersection points of The Rideau Trail. Say you wanted to access The Rideau Trail from Carleton Universtiy, but you only wanted to travel along the roads to get to it. In this scenario, we will be using the Roads_Centrelines layer and the Roads_Centreline_Intersections points that were previously created to find the shortest distances possible to each of the places where a road and The Rideau Trail intersect. This analysis aims to answer the question, how do I get to the Rideau Trail using roads from my location in Ottawa?

			NOTE: This analysis was conducted using QGIS v3.4

← Older revision		Revision as of 17:12, 6 October 2020
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	Opening up the attribute table of the new Shortest path layer will reveal several attribute columns, however, the columns of most interest include the start and cost columns. The start and cost columns represent the distance between the start point (start) and the end point (cost) in layer units. In this case, the start and the cost are represented in latitude and longitude coordinates.		Opening up the attribute table of the new Shortest path layer will reveal several attribute columns, however, the columns of most interest include the start and cost columns. The start and cost columns represent the distance between the start point (start) and the end point (cost) in layer units. In this case, the start and the cost are represented in latitude and longitude coordinates. If interested, you can use these coordinates to calculate the exact distance between each start and end point.

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-Clicking on the Shortest path (point to layer) tool will bring up a separate window. In the Parameters window,the Vector layer representing network will be the Road_Centrelines layer. The Path type to calculate will be Shortest. The vector layer with end points will be the Roads_Centerlines_Intersections layer.
+Clicking on the Shortest path (point to layer) tool will bring up a separate window. In the Parameters window, the ''Vector layer representing network'' will be the Road_Centrelines layer. The ''Path type to calculate'' will be Shortest. The ''Vector layer with end points'' will be the Roads_Centerlines_Intersections layer.
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-Before hitting Run, you will have to select a starting point for the algorithm to calculate the shortest distance. In the parameters window, click on the Start point (x, y). This will minimize the window to your map view, and your cursor will be a cross hair. Select an area on Carleton University's campus.
+Before hitting ''Run'', you will have to select a starting point for the algorithm to calculate the shortest distance. In the parameters window, click on the ''Start point (x, y)''. This will minimize the window to your map view, and your cursor will be a cross hair. Select an area on Carleton University's campus.
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-Once you have selected a starting point, the Shortest path (point to layer) window will maximize, and you may now hit the Run function in the bottom right corner of the window. Running this tool will create a temporary layer, and will demonstrate all the different shortest pathway possibilities to get to any of the locations where the road intersects The Rideau Trail as if you were travelling by the Roads_Centrelines layer.
+Once you have selected a starting point, the Shortest path (point to layer) window will maximize, and you may now hit the ''Run'' function in the bottom right corner of the window. Running this tool will create a temporary layer, and will demonstrate all the different shortest pathway possibilities to get to any of the locations where the road intersects The Rideau Trail as if you were travelling by the Roads_Centrelines layer.

← Older revision		Revision as of 17:05, 6 October 2020
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	== '''Shortest Path Analysis''' ==		== '''Shortest Path Analysis''' ==

	Using the intersections layers created in the [[Path_Analysis_with_Vector_Data_Using_QGIS#Process\|Process]] section, we will now use a Network Analysis tool within QGIS to calculate the shortest path between any random point in Ottawa and the intersection points of The Rideau Trail. Say you wanted to access The Rideau Trail from Carleton Universtiy, but you only wanted to travel along the roads to get to it. In this scenario, we will be using the Roads_Centrelines layer and the Roads_Centreline_Intersections points that were previously created to find the shortest distances possible to each of the places where ~~the~~ ~~roads~~ and The Rideau Trail intersect. This analysis aims to answer the question, how do I get to the Rideau Trail using roads from my location in Ottawa?		Using the intersections layers created in the [[Path_Analysis_with_Vector_Data_Using_QGIS#Process\|Process]] section, we will now use a Network Analysis tool within QGIS to calculate the shortest path between any random point in Ottawa and the intersection points of The Rideau Trail. Say you wanted to access The Rideau Trail from Carleton Universtiy, but you only wanted to travel along the roads to get to it. In this scenario, we will be using the Roads_Centrelines layer and the Roads_Centreline_Intersections points that were previously created to find the shortest distances possible to each of the places where a road and The Rideau Trail intersect. This analysis aims to answer the question, how do I get to the Rideau Trail using roads from my location in Ottawa?

← Older revision		Revision as of 16:32, 6 October 2020
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	== '''Shortest Path Analysis''' ==		== '''Shortest Path Analysis''' ==

	Using the intersections layers created in the [[Path_Analysis_with_Vector_Data_Using_QGIS#Process\|Process]] section, we will now use a Network Analysis tool within QGIS to calculate the shortest path between any random point in Ottawa and the intersection points of The Rideau Trail. Say you wanted to access The Rideau Trail from Carleton Universtiy, but you only wanted to travel along the roads to get to it. In this scenario, we will be using the Roads_Centrelines layer and the Roads_Centreline_Intersections points that were previously created to find the shortest distances possible to each of the places where the roads and The Rideau Trail intersect.		Using the intersections layers created in the [[Path_Analysis_with_Vector_Data_Using_QGIS#Process\|Process]] section, we will now use a Network Analysis tool within QGIS to calculate the shortest path between any random point in Ottawa and the intersection points of The Rideau Trail. Say you wanted to access The Rideau Trail from Carleton Universtiy, but you only wanted to travel along the roads to get to it. In this scenario, we will be using the Roads_Centrelines layer and the Roads_Centreline_Intersections points that were previously created to find the shortest distances possible to each of the places where the roads and The Rideau Trail intersect. This analysis aims to answer the question, how do I get to the Rideau Trail using roads from my location in Ottawa?

@@ Line 121: / Line 121: @@
 Using the intersections layers created in the [[Path_Analysis_with_Vector_Data_Using_QGIS#Process|Process]] section, we will now use a Network Analysis tool within QGIS to calculate the shortest path between any random point in Ottawa and the intersection points of The Rideau Trail. Say you wanted to access The Rideau Trail from Carleton Universtiy, but you only wanted to travel along the roads to get to it. In this scenario, we will be using the Roads_Centrelines layer and the Roads_Centreline_Intersections points that were previously created to find the shortest distances possible to each of the places where the roads and The Rideau Trail intersect.
 [[File:Figure_12..png|caption|border|1000px]]
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 Next, open the QGIS toolbox by clicking the gear icon on the Attributes toolbar. If you cannot find this icon, go to Processing > Toolbox.
 [[File:Figure13 MM.png|caption|border|1000px|]]
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 After clicking the Toolbox, click on the drop-down menu beside Network analysis. There will be several options, but click on the Shortest path (point to layer) tool. The Shortest path (point to layer) tool is an algorithm that calculates the shortest path between a given start point and multiple end points using a vector layer.
 [[File:Figure14 MM.png|caption|border|1000px]]
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 Clicking on the Shortest path (point to layer) tool will bring up a separate window. In the Parameters window,the Vector layer representing network will be the Road_Centrelines layer. The Path type to calculate will be Shortest. The vector layer with end points will be the Roads_Centerlines_Intersections layer.
 [[File:Figure15 MM.png|caption|border|500px]]
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 Before hitting Run, you will have to select a starting point for the algorithm to calculate the shortest distance. In the parameters window, click on the Start point (x, y). This will minimize the window to your map view, and your cursor will be a cross hair. Select an area on Carleton University's campus.
 [[File:Figure16 MM.png|caption|border|1000px]]
@@ Line 156: / Line 161: @@
 Once you have selected a starting point, the Shortest path (point to layer) window will maximize, and you may now hit the Run function in the bottom right corner of the window. Running this tool will create a temporary layer, and will demonstrate all the different shortest pathway possibilities to get to any of the locations where the road intersects The Rideau Trail as if you were travelling by the Roads_Centrelines layer.
 [[File:Figure17 MM.png|caption|border|1000px]]
@@ Line 163: / Line 169: @@
 Opening up the attribute table of the new Shortest path layer will reveal several attribute columns, however, the columns of most interest include the start and cost columns. The start and cost columns represent the distance between the start point (start) and the end point (cost) in layer units. In this case, the start and the cost are represented in latitude and longitude coordinates.
 [[File:Figure18 MM.png|caption|border|500px]]