One of the initial challenges that you can encounter as a novice SWAT user who wants to use CORINE Land Use/Land Cover (LULC) maps is converting the LULC to SWAT LULC:
Here is how I addressed this problem in my first SWAT project, which is on a 150-km2 watershed located in northwestern Turkey:
Corine2006 Code/Description: SWAT:
121/Industrial or commercial units UCOM
122/Road and rail networks and associated land UTRN
243/Land principally occupied by agriculture with significant areas of natural vegetation AGRL
231/Pastures PAST
324/Transitional woodland scrub RNGB
242(1)*/Complex cultivation patterns AGRL
311/Broad-leaved forest FRSD
312/Coniferous forest FRSE
212(1)*/Permanently irrigated land AGRL
313/Mixed forest FRST
321/Natural grassland RNGE
112(2)*/Discontinuous urban fabric URLD
211(1)*/Non-irrigated arable land AGRC
512/Water bodies WATR
411/Inland marshes WETN
(*): Typical CORINE2006 LULC codes are three-digit. Some of the CORINE2006 codes in the map provided to me by my fellow researchers contained four digits. So, you can disregard the last digit given in parentheses.
You can download the small .txt that I wrote for my ArcSWAT (version 2012.10.1.15 released on 6/20/14) project from here. You can edit this file as you please and use it in your ArcSWAT project.
Please check out the following references, which helped me quite a bit during my own conversion process:
1. http://www.eea.europa.eu/publications/COR0-landcover
2. http://ec.europa.eu/agriculture/publi/landscape/about.htm
3. http://www.eea.europa.eu/data-and-maps/data/corine-land-cover-2006-raster-2/corine-land-cover-classes-and/clc_legend.csv
Showing posts with label ArcSWAT. Show all posts
Showing posts with label ArcSWAT. Show all posts
Sunday, July 20, 2014
Thursday, April 24, 2014
SWAT: Soil Data for non-US Study Areas
This blog post addresses:
a. Acquiring soil data & soil map for modeling a non-US study area using ArcSWAT
b. Basic interpretation of the imported soil data using freely available online documents
a. Soil Data
Default ArcSWAT database (SWAT2012.mdb) does include the US soil data in usersoil table.
World soil data can be imported from MWSWAT database (mwswat2012.mdb). Therefore, you need to install MapWindow and MWSWAT if you want to have access to mwswat2012.mdb.
After you complete the installation, you can find mwswat2012.mdb under the MWSWAT2012 subdirectory of MapWindow directory (e.g., C:\MapWindow\Plugins\MWSWAT2012).
If you want to bypass this procedure, feel free to download custom SWAT2012.mdb I use in my project that includes the worldwide soil data in user table.
Once you download the custom SWAT2012.mdb, you can simply replace the original file with the newly downloaded custom file.
Soil Map
You can practically download soil maps in raster format for any place in the world from the download section of MWSWAT site. You may need to pre-process the raster file and clip it in a GIS software, which is beyond the scope of this post. You may refer to MWSWAT documents for pre-processing tips.
You will notice that every cell, which is also called as soil mapping unit, in the downloaded raster file has a unique value. The values refer to the specific soils listed in usersoil table of the custom SWAT2012.mdb.
For instance, if the value of a cell is 1736, that cell or soil mapping unit has Vp19-3a-1736 soil. I will explain how we can interpret the abbreviations used in the soil name below.
In ArcSWAT, you will need to link the values in your soil map with the corresponding soil data. The instructions are available in pp. 17-18 of ArcSWAT 2012 User's Guide. I share the simple soil lookup table I wrote for my project as an example.
b. Soil Data Interpretation
Information on the soil taxonomy is typically required in the technical document preparation phase. Therefore, SWAT user needs to know what the SNAM field abbreviation in usersoil table of SWAT2012.mdb stand for.
The soil data in the custom SWAT2012.mdb is compiled from 1:5000000 scale World Soil Map (version 3.6) of the United Nations Food and Agriculture Organization (FAO).
MWSWAT site includes two documents that can be used for the data interpretation, namely readme.pdf and notes.txt.
FAO has its own web page dedicated to the World Soil Map. Two Excel files (BasicFilesSC.xls and WORLD764.xls) acquired from this web page are particularly useful for the data interpretation purposes.
Below I give an example from my own SWAT project where I extracted the taxonomic information from the abbreviations
Example:
Unique abbreviation for the soil mapping unit: Ao111-2bc-3003
Ao stands for Orthic Acrisols (Reference Used: readme.pdf)
Summary Information (Reference Used: BasicFilesSC.xls) : Orthic Acrisols as the `dominant soil` constitutes 40% of the map unit (MU). 100% of the map unit has medium texture. 75% of the MU has rolling topography and 25% of the MU has mountainous topography.
Detailed Information (Reference Used: WORLD764.xls): Map unit consists of
20% Orthic Acrisols-2b texture-slope class
20% Orthic Acrisols-2c texture-slope class
30% Dystric Cambisols (Bd)-2b texture-slope class
10% Calcic Cambisols (Bk)-2b texture-slope class
10% RENDZINAS (E)-2b texture-slope class
10% LITHOSOLS (I) 10% of the map unit
Texture, topography/slope classifications can be found in readme.pdf
a. Acquiring soil data & soil map for modeling a non-US study area using ArcSWAT
b. Basic interpretation of the imported soil data using freely available online documents
a. Soil Data
Default ArcSWAT database (SWAT2012.mdb) does include the US soil data in usersoil table.
World soil data can be imported from MWSWAT database (mwswat2012.mdb). Therefore, you need to install MapWindow and MWSWAT if you want to have access to mwswat2012.mdb.
After you complete the installation, you can find mwswat2012.mdb under the MWSWAT2012 subdirectory of MapWindow directory (e.g., C:\MapWindow\Plugins\MWSWAT2012).
If you want to bypass this procedure, feel free to download custom SWAT2012.mdb I use in my project that includes the worldwide soil data in user table.
Once you download the custom SWAT2012.mdb, you can simply replace the original file with the newly downloaded custom file.
Soil Map
You can practically download soil maps in raster format for any place in the world from the download section of MWSWAT site. You may need to pre-process the raster file and clip it in a GIS software, which is beyond the scope of this post. You may refer to MWSWAT documents for pre-processing tips.
You will notice that every cell, which is also called as soil mapping unit, in the downloaded raster file has a unique value. The values refer to the specific soils listed in usersoil table of the custom SWAT2012.mdb.
For instance, if the value of a cell is 1736, that cell or soil mapping unit has Vp19-3a-1736 soil. I will explain how we can interpret the abbreviations used in the soil name below.
In ArcSWAT, you will need to link the values in your soil map with the corresponding soil data. The instructions are available in pp. 17-18 of ArcSWAT 2012 User's Guide. I share the simple soil lookup table I wrote for my project as an example.
b. Soil Data Interpretation
Information on the soil taxonomy is typically required in the technical document preparation phase. Therefore, SWAT user needs to know what the SNAM field abbreviation in usersoil table of SWAT2012.mdb stand for.
The soil data in the custom SWAT2012.mdb is compiled from 1:5000000 scale World Soil Map (version 3.6) of the United Nations Food and Agriculture Organization (FAO).
MWSWAT site includes two documents that can be used for the data interpretation, namely readme.pdf and notes.txt.
FAO has its own web page dedicated to the World Soil Map. Two Excel files (BasicFilesSC.xls and WORLD764.xls) acquired from this web page are particularly useful for the data interpretation purposes.
Below I give an example from my own SWAT project where I extracted the taxonomic information from the abbreviations
Example:
Unique abbreviation for the soil mapping unit: Ao111-2bc-3003
Ao stands for Orthic Acrisols (Reference Used: readme.pdf)
Summary Information (Reference Used: BasicFilesSC.xls) : Orthic Acrisols as the `dominant soil` constitutes 40% of the map unit (MU). 100% of the map unit has medium texture. 75% of the MU has rolling topography and 25% of the MU has mountainous topography.
Detailed Information (Reference Used: WORLD764.xls): Map unit consists of
20% Orthic Acrisols-2b texture-slope class
20% Orthic Acrisols-2c texture-slope class
30% Dystric Cambisols (Bd)-2b texture-slope class
10% Calcic Cambisols (Bk)-2b texture-slope class
10% RENDZINAS (E)-2b texture-slope class
10% LITHOSOLS (I) 10% of the map unit
- 5% LITHOSOLS (I)-2b texture-slope class
- 5% LITHOSOLS (I)-2c texture-slope class
Texture, topography/slope classifications can be found in readme.pdf
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