Digitizing in QGIS - Revision history

Spatula mcguilicutty: /* Merge Selected Features tool */

2026-10-06T18:37:48Z

Merge Selected Features tool

Spatula mcguilicutty: /* Move Feature(s) tool */

2026-10-06T18:36:55Z

Move Feature(s) tool

Spatula mcguilicutty: /* Advanced Digitizing */

2026-10-06T18:33:55Z

Advanced Digitizing

Spatula mcguilicutty: /* Conclusion */

2026-10-04T02:03:40Z

Conclusion

Spatula mcguilicutty: /* Conclusion */ Adding a second paragraph

2026-10-04T01:59:12Z

Conclusion: Adding a second paragraph

Spatula mcguilicutty: /* Advanced Digitizing */

2026-10-04T01:55:59Z

Advanced Digitizing

Spatula mcguilicutty: /* Move Feature(s) tool */

2026-10-03T22:56:04Z

Move Feature(s) tool

Spatula mcguilicutty: Adding Advanced Digitizing section

2026-10-03T22:01:11Z

Adding Advanced Digitizing section

Spatula mcguilicutty: /* Final Vector Model */

2026-10-03T20:34:41Z

Final Vector Model

Spatula mcguilicutty: /* Final Vector Model */

2026-10-03T20:34:15Z

Final Vector Model

@@ Line 346: / Line 346: @@
 ====Merge Selected Features tool====
-In this example I have digitized the major roads present in my aerial image, as shown below, but would like to merge some of the roads that intersect with each other.
+In this example you have digitized the major roads present in the aerial image, as shown below, but would like to merge some of the roads that intersect with each other.
 [[File:PreMerge.png|500px]]

@@ Line 292: / Line 292: @@
 This tool allows you to change the location of a digitized feature after it has been created. It can be used for points, polylines, or polygons. It is useful for adjusting the position of a feature that is not quite where you intended to place it, or which you digitized in the wrong location.
-In this example I am placing points on the locations of all the red cars in my aerial image and have misplaced a point on a white car.
+In this example you are placing points on the locations of all the red cars in the aerial image and have misplaced a point on a white car.
 [[File:PointToMove.png|500px]]
-*While in editing mode I will click the ‘Move Feature(s)’ icon [[File:MoveFeatures.png]]
+*While in editing mode you will click the ‘Move Feature(s)’ icon [[File:MoveFeatures.png]]
-*Then I will point the crosshair at the point I want to move and click on it
+*Then you will point the crosshair at the point you want to move and click on it
-*A small red circle will appear under the crosshair, and I will point the red circle at where I want to move the selected point, as shown below
+*A small red circle will appear under the crosshair, and you will point the red circle at where you want to move the selected point, as shown below
 [[File:MovingPoint.png|500px]]
-*Finally, I will click on the desired location and that will move the point
+*Finally, you will click on the desired location and that will move the point
 [[File:MovedPoint.png|500px]]
-*Once I am done digitizing with this layer I will click ‘Save Layer Edits’ [[File:SaveLayerEdits.png]] and that will save all the changes made
+*Once you are done digitizing with this layer you will click ‘Save Layer Edits’ [[File:SaveLayerEdits.png]] and that will save all the changes made
 The same process applies for moving polylines and polygons.

@@ Line 286: / Line 286: @@
 [[File:UserManualTable.png|frame|Source: https://docs.qgis.org/3.44/en/docs/user_manual/working_with_vector/editing_geometry_attributes.html#advanced-digitizing|none]]
-This tutorial will focus on demonstrating how to use three of these tools: the Move Feature(s) [[File:MoveFeatures.png]] tool and the “Split Features” [[File:SplitFeatures.png]] and “Merge Selected Features” tools [[File:MergeFeatures.png]].
+This tutorial will focus on demonstrating how to use three of these tools: the Move Feature(s) [[File:MoveFeatures.png]] tool and the “Split Features” [[File:SplitFeatures.png]] and “Merge Selected Features” [[File:MergeFeatures.png]] tools.
 ===Move Feature(s) tool===

← Older revision		Revision as of 02:03, 4 October 2026
Line 389:		Line 389:
	Following this tutorial, you should have a completed vector model that was created by taking an aerial photo and digitizing the geographical features and land use classes and which provides necessary information from that specific region. However, the amount of human error is vital to consider before completing any type of analysis. User error will be present throughout this tutorial as boundaries between layers are not always straight lines. Many different types of error assessment models are available for use to assess your accuracy when creating classes.		Following this tutorial, you should have a completed vector model that was created by taking an aerial photo and digitizing the geographical features and land use classes and which provides necessary information from that specific region. However, the amount of human error is vital to consider before completing any type of analysis. User error will be present throughout this tutorial as boundaries between layers are not always straight lines. Many different types of error assessment models are available for use to assess your accuracy when creating classes.

	This tutorial should also have taught you how to do basic digitizing, including creating points, lines, and polygons, and editing the vertices of digitized features. It should also have taught you some more advanced digitizing techniques, including how to move created features, and merge or split features in a layer. Hopefully this tutorial has inspired you to dig even deeper into digitizing possibilities using QGIS. Information on other available tools can be found in the [https://docs.qgis.org/3.44/en/docs/user_manual/working_with_vector/editing_geometry_attributes.html#advanced-digitizing\|QGIS User Manual]. Happy digitizing!		This tutorial should also have taught you how to do basic digitizing, including creating points, lines, and polygons, and editing the vertices of digitized features. It should also have taught you some more advanced digitizing techniques, including how to move created features, and merge or split features in a layer. Hopefully this tutorial has inspired you to dig even deeper into digitizing possibilities using QGIS. Information on other available tools can be found in the [https://docs.qgis.org/3.44/en/docs/user_manual/working_with_vector/editing_geometry_attributes.html#advanced-digitizing\| QGIS User Manual]. Happy digitizing!

@@ Line 388: / Line 388: @@
 ==Conclusion==
 Following this tutorial, you should have a completed vector model that was created by taking an aerial photo and digitizing the geographical features and land use classes and which provides necessary information from that specific region. However, the amount of human error is vital to consider before completing any type of analysis. User error will be present throughout this tutorial as boundaries between layers are not always straight lines. Many different types of error assessment models are available for use to assess your accuracy when creating classes.
+This tutorial should also have taught you how to do basic digitizing, including creating points, lines, and polygons, and editing the vertices of digitized features. It should also have taught you some more advanced digitizing techniques, including how to move created features, and merge or split features in a layer. Hopefully this tutorial has inspired you to dig even deeper into digitizing possibilities using QGIS. Information on other available tools can be found in the [https://docs.qgis.org/3.44/en/docs/user_manual/working_with_vector/editing_geometry_attributes.html#advanced-digitizing|QGIS User Manual]. Happy digitizing!

@@ Line 311: / Line 311: @@
 The same process applies for moving polylines and polygons.
+===Split Features and Merge Selected Features tools===
+These two tools are essentially each others’ opposites. The Split Features tool is used to split a polygon or polyline feature into two separate features at a specified location. This can be useful for splitting a road at intersections or splitting a building polygon into multiple polygons that represent wings of the building, to provide two possible use cases. When features are split, the resulting features have identical attribute fields.
+The Merge Selected Features tool, on the other hand, merges features that have been selected within a layer into a single feature. It can be used on point, polyline, or polygon layers and for features that have common boundaries and those that do not. If the merged features do not have common boundaries, the resulting feature is a multipolygon/multipolyline,/multipoint feature. When features are merged you must decide how the merged feature’s attribute tables are combined.
+====Split Features tool====
+In this example a polygon of the Mackenzie Building at Carleton University will be split into seven different polygons representing the four blocks in the building and the three connecting stairwells. The polygon is shown below.
+[[File:Mackenzie.png|500px]]
+*While in editing mode you will first activate the Split Features tool by clicking on its icon [[File:SplitFeatures.png]]
+*The mouse icon will turn into a scope target. To split the polygon you will click on one side of the polygon and then move the mouse to another side of the polygon and click again, which will create a red line, as shown below.
+[[File:Splitting.png|400px]]
+*Then you will right-click which will finalize the split, as shown below
+[[File:BeenSplit.png|400px]]
+*It is also possible to create more complex split lines by adding more vertexes to the red line before right-clicking. A dramatized example is shown below.
+[[File:DramatizedSplit.png|400px]]
+*Once all of the required splitting is done, the Mackenzie Building polygons look like this and each of the polygons can be selected separately:
+[[File:Split.png|400px]]
+The same process applies for splitting polylines, except that, by definition, the splitting line only touches the polyline at one point.
+====Merge Selected Features tool====
+In this example I have digitized the major roads present in my aerial image, as shown below, but would like to merge some of the roads that intersect with each other.
+[[File:PreMerge.png|500px]]
+*While in editing mode you will first select all of the roads that you would like to merge into one feature
+[[File:SelectedRoads.png]]
+*Then you will click the Merge Selected Features button [[File:MergeFeatures.png]]
+*This will open the Merge Features dialog box where you will have to decide how the features' attributes will be treated once they are merged.
+[[File:MergeDialogBox.png]]
+*The options for how to merge each field depend on the field type, but they each have the option to choose a value from one of the selected features, to manually set the value, to set it to NULL, or to skip the field and not determine a merged value. You are also able to choose the value from the largest/longest feature. The figure below shows the options available for a numerical field.
+[[File:NumericalMerge.png]]
+*For this example, the merged ‘id’ field will be the median of the merged features while the ‘Roads’ field will be a concatenation of all of the merged features.
+[[File:MergedAttributes.png]]
+*Once the merging options are chosen and you press ‘Ok’ the selected polylines will be successfully merged.
+[[File:MergedComplete.png]]
+*Once you are done merging these features you will click ‘Save Layer Edits’ [[File:SaveLayerEdits.png]] and that will save all the changes made
+The same principles apply for merging point and polygon layers and features do not need to be coincident with each other to be merged.
 ==Final Vector Model==

@@ Line 271: / Line 271: @@
 *The window will close and within your attribute table you should now have a calculated area for the area column in m<sup>2</sup>
-====Final Vector Model====
+==Final Vector Model==
 * When you have digitized all the desired geographical features in your image and classified the parcels of land into different land use classifications, your final vector model should be similar to this:
             [[File:finalvectormodel.png]]