Site suitability using SAGA GIS - Revision history

Smitchs: /* Software required (SAGA GIS and QGIS) */

2021-01-13T15:20:17Z

Software required (SAGA GIS and QGIS)

Sabeeh Syed at 05:32, 23 December 2020

2020-12-23T05:32:38Z

Sabeeh Syed: /* Creating Constraints */

2020-12-23T05:28:29Z

Creating Constraints

Sabeeh Syed: /* Creating Constraints */

2020-12-23T05:21:28Z

Creating Constraints

Sabeeh Syed: /* Creating Constraints */

2020-12-23T05:18:44Z

Creating Constraints

Sabeeh Syed: /* Creating Constraints */

2020-12-23T05:17:57Z

Creating Constraints

Sabeeh Syed: /* Creating Constraints */

2020-12-23T04:51:56Z

Creating Constraints

Sabeeh Syed: /* Defining a Project Area and Creating Grid Maps */

2020-12-23T04:38:23Z

Defining a Project Area and Creating Grid Maps

Sabeeh Syed: /* Defining a Project Area and Creating Grid Maps */

2020-12-23T04:37:49Z

Defining a Project Area and Creating Grid Maps

Sabeeh Syed: /* Defining a Project Area and Creating Grid Maps */

2020-12-23T04:34:41Z

Defining a Project Area and Creating Grid Maps

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 == Software required (SAGA GIS and QGIS) ==
-System for Automated Geoscientific Analyses, also known as [http://www.saga-gis.org/en/index.html SAGA], is a great free and open source software (FOSS GIS tool). SAGA is great tool that offers users a comprehensive and growing set of geoscientific methods and modules that allow for manipulating and analyzing vector or raster data. SAGA also allows for users to script in commands using its Command Line Interpreter (CMD). Despite being not very user friendly, the CMD has the advantage that it can be executed from batch script files, which in turn enables a further automation of complex work flows and the routine processing of mass data. QGIS is available for Windows and Linux. Download the latest version of [https://sourceforge.net/projects/saga-gis/files/SAGA%20-%207/ SAGA (v.7.9.0)] to begin this tutorial.
+System for Automated Geoscientific Analyses, also known as [http://www.saga-gis.org/en/index.html SAGA], is a great free and open source software package (FOSS GIS tool). It offers users a comprehensive and growing set of geoscientific methods and modules that allow for manipulating and analyzing vector or raster data. SAGA also allows for users to script in commands using its Command Line Interpreter (CMD). Despite being not very user friendly, the CMD has the advantage that it can be executed from batch script files, which in turn enables a further automation of complex work flows and the routine processing of mass data. QGIS is available for Windows and Linux.
+Download the latest version of [https://sourceforge.net/projects/saga-gis/files/SAGA%20-%207/ SAGA (v.7.9.0)] to begin this tutorial.
 Additionally, you should also have [https://www.qgis.org/en/site/forusers/download.html QGIS (v.3.14)] installed as it is required in the very preliminary steps to make the data easier to work with.
 == Tutorial ==

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 [[File:Areas in green = suitable (forest + urban).png|500px|thumb|none|Reclassified map of forested and urban areas constraint]]
 === Using Boolean Aggregation to Create a Site Suitability Map ===
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  - Set '''Data Type''' to '''4 byte floating point number'''
  - Hit '''Execute'''
+[[File:Settings to create site suitability map (grid calculator).png|350px|thumb|none|Settings for grid calculator to create a site suitability map]]
 The result should be something similar to below:
+[[File:Site suitability map.png|500px|thumb|none|Site suitability map created using constraints and factors]]
-insert photo
+Areas in red are the areas that are deemed to be suitable for building of a windfarm.
 The output map has the value 1 where all areas of suitability intersect for all criteria and the value 0 for all areas that are unsuitable for one or more of the criteria. Suitability in one criterion cannot compensate for a lack of suitability in any other layer. They do not trade off. By meeting all criteria, the result is the best locations possible for the building of a wind farm.

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 [[File:Grid calculator (wetland+waterbodies).png|350px|thumb|none|Grid Calculator settings]]
 Upon creating this new grid map, it must be reclassified. Navigate to '''Grid''' -> '''Tools''' -> '''Reclassify Grid Values''' and use the following settings:
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  - For ''' Data Storage Type''' select '''[same as input grid]'''
  - For '''No Data Value''' under the Output Grid options, leave as '''No Data Value of Input Grid'''
+[[File:Reclassify grid values (wetland+water).png|350px|thumb|none|Reclassify settings]]
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  - For '''Type''' select '''Fixed'''
  - For '''Distance''' input a value of your choosing. The value chosen is presented in feet. Knowing this we chose a value of 250. If cell is to be chosen instead of fixed, then the value entered is the number of cells wide you wish for the buffer to be.
+[[File:Grid buffer(wetland+water).png|350px|thumb|none|Grid buffer settings]]
@@ Line 140: / Line 148: @@
  - For '''No Data Value''' under the Output Grid options, leave as '''No Data Value of Input Grid'''
+[[File:Lookuptable (wetland+water).png|350px|thumb|none|Reclassification via lookup table settings]]
-Once completed you should have something that looks similar to this:
-insert photo
-As we can seen in the photo, all the areas that are in blue are areas that are outside the buffer range and can be considered areas that are viable for a windfarm.
+Once completed you should have something that looks similar to this:
+[[File:Areas in blue = suitable (wetland+water).png|500px|thumb|none|Reclassified map of waterbodies and wetland constraint]]
-Repeat all the steps above for the Forests and Urban shapefiles to create a constraint for Forests and Urban areas. The result should look similar to below:
-Insert photo
+As we can seen in the photo, all the areas that are in blue are areas that are outside the buffer range and can be considered areas that are viable for a windfarm.
+Repeat all the steps above for the Forests and Urban shapefiles to create a constraint for Forests and Urban areas. The result should look similar to below:
+[[File:Areas in green = suitable (forest + urban).png|500px|thumb|none|Reclassified map of forested and urban areas constraint]]
-[[File:WhatItShouldLookLike.png|650px|thumb|none|Map of Ottawa region, with accidents categorized by type. Wards of Ottawa converted to grayscale to better emphasize difference in accident types.]]
 === Using Boolean Aggregation to Create a Site Suitability Map ===

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  - Right click the newly created grid and rename it to something of your liking
-[[File:Grid calculator (wetlands+waterbodies).png|350px|thumb|none|Grid Calculator settings]]
+[[File:Grid calculator (wetland+waterbodies).png|350px|thumb|none|Grid Calculator settings]]
 Upon creating this new grid map, it must be reclassified. Navigate to '''Grid''' -> '''Tools''' -> '''Reclassify Grid Values''' and use the following settings:

@@ Line 107: / Line 107: @@
  - Right click the newly created grid and rename it to something of your liking
-[[File:Grid calculator (wetlands+water).png|350px|thumb|none|Grid Calculator settings]]
+[[File:Grid calculator (wetlands+waterbodies).png|350px|thumb|none|Grid Calculator settings]]
 Upon creating this new grid map, it must be reclassified. Navigate to '''Grid''' -> '''Tools''' -> '''Reclassify Grid Values''' and use the following settings:

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  - Leave the '''<<Grid''' option as '''<create>'''
  - Hit '''Execute'''
+[[File:Shapes to grid.png|350px|thumb|none|Shapes to grid settings]]
 Repeat the above for the wetlands shapefile as well.
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 [[File:WhatItShouldLookLike.png|650px|thumb|none|Map of Ottawa region, with accidents categorized by type. Wards of Ottawa converted to grayscale to better emphasize difference in accident types.]]
 === Using Boolean Aggregation to Create a Site Suitability Map ===

← Older revision		Revision as of 04:38, 23 December 2020
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	[[File:Addshape to map projection layer.png\|500px\|thumb\|none\|Creating a new shape in the MapProjectionLayer]]		[[File:Addshape to map projection layer.png\|500px\|thumb\|none\|Creating a new shape in the MapProjectionLayer]]



	[[File:Tracing.png\|500px\|thumb\|none\|Tracing the boundaries of the Land Used shapefiles]]		[[File:Tracing.png\|500px\|thumb\|none\|Tracing the boundaries of the Land Used shapefiles]]

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 Once completed, the Layer will have a new instance, with the ID of 0. This will be used to create the grid system that will host the other grids we make in the next few steps.
-To create a new grid system, in the '''Tools''' tab, click '''Grid''' -> '''Tools''' -> '''Create Grid System'''. In the window that opens, change the '''Cell Size''' to 30, the '''Initialization Value''' to 1 and the '''Extent Definition''' to '''One or more shapes layers'''. In the '''>> Shapes Layers''' field, input the polygon that you created. This will create a new grid definition with the value: "30; 3647x 3868y; 321532.093525x 5427575.539568y"
+To create a new grid system, in the '''Tools''' tab, click '''Grid''' -> '''Tools''' -> '''Create Grid System'''. In the window that opens, change the '''Cell Size''' to 30, the '''Initialization Value''' to 1 and the '''Extent Definition''' to '''One or more shapes layers'''. In the '''>> Shapes Layers''' field, input the polygon that you created.
+[[File:Creating grid system.png|300px|thumb|none|Creating a grid system using a shape layer]]
+This will create a new grid definition with a value similar to: "30; 3647x 3868y; 321532.093525x 5427575.539568y"