Global Spatial Data Infrastructure (GSDI) Training Workshop

Theme: “Spatial Data Infrastructure Capacity Building for West-African Professionals”(Date: 22nd – 28th May, 2011)

Practical Demonstration on

GIS in Land Suitability Mapping for Precision Farming

Regional Centre for Training in Aerospace Surveys (RECTAS)Off Road 1, Obafemi Awolowo University Campus, P.M.B. 5545, Ile-Ife, Nigeria

byEnaruvbe, G.O.

Goals of GIS in Precision Farming

• Improve soil management techniques

• Improve yield per hectare of farmland

• Improve profit per farm input

• Decision support for efficient management of farming input

Goals of GIS in Precision Farming

• GIS can also be applied in other aspects of farming

– Precision fertilizer application

– Productivity estimation

– Monitoring crop diseases

– Among many other areas

Goals of GIS in Precision Farming

• The goal of this presentation is to demonstrate the use of ArcGIS in soil suitability evaluation.

• Available dataset include geo-referenced soil data

• This is saved in a folder “soil25052011”on the desktop of your computer.

Expected Result of this Exercise

• At the end of this exercise, we should be able to identify areas that are suitable, moderately suitable and highly suitable for the production of crop ‘X` based on soil characteristics only

Launch ArcGIS 9.x

Program| ArcGIS | ArcCatalog

Launch ArcGIS 9.x

Connect to Folder containing the data

File | Connect folder | Navigate to “soil25052011” on the desktop

Connect to Folder containing the data

File | Connect folder | Navigate to “soil25052011” on the desktop

Connect to Folder containing the data

File | Connect folder | Navigate to “soil25052011” on the desktop

Connect to Folder containing the data

Lunch ArcMap

Tools | ArcMap

Launch ArcMap

Lunch ArcMap

OK

Add Data

File | Add Data

Add Data

Double click “sOIL PROP.xls”

Add Data

Select Sheet$1 | Add

Add DataDisplay XY Data

Right-click the theme display on the TOC to the left and select Display XY Data

Click Edit

Click select…

Double click Geographic Coordinate Systems

Double click World

Double Click WGS 1984.prj & click Ok until points are displayed on the ArcMap screen

Add Data

Select sheet$1 Events

Convert data from events to theme

Right Click sheet$1 | Data | export data. This converts the sheet$1 event to shapefile

The theme that appears now is a shapefile

Raster Data Interpolation

In ToolsBox, 3D Analyst | Raster interpolation | Krigging(you can also use IDW)

Double click Krigging

Data Interpolation

Select shapefile theme ( not event) to interpolate e.g. Sample | for Z value pick the property of interest e.g. pH then OK

Interpolated Surface

Output is a surface interpolation of pH-Value

Interpolated Surface

• Repeat steps in slides 26-30 for all the properties you want to include as criteria in the suitability evaluation.

Reclass soil

Raster Reclass | Reclassify

Data Classification

Raster Reclass | Double click Reclassify

Select Layer to Reclass

Input raster select raster to reclass e.g. pH | Classify

Data Classify

Select input raster | Click Classify

Classification method choose equal interval | class choose the number of classes desired e.g. 3 then OK

Classification method choose equal interval | class choose the number of classes desired e.g. 3 then OK

Output of reclass operation

Reclass

• Repeat steps in slides 32-38 to reclass all the criteria required

Overlay Operation

Raster Math | double click Plus

Overlay Operation

Select reclassified criteria e.g. pH reclass and P reclass as two criteria for overlay

• Repeat steps in slide 40 & 41, but always take the result of the last overlay operation as input 1 and any other criteria as input two.

• Do this till you satisfy all criteria of interest e.goverlay of N, P, K and Yield

• This means you keep increasing the criteria and you classes are likely to keep changing as you do that.

•

Label the Classes

Right click the reclass theme | open attribute table| Options | Add Events

Name e.g. Classes| Type is text| OK

Edit Table

Editor | Start Editing. You may be prompted for the folder to edit. Choose the arcinfoworkspace folder

Identify Classes

Double click on the cells under classes and type in Suitability classes e.g. Highly suitable, moderately suitable, suitable or not suitable,

You now stop editing and close dialogue box

Double Click Reclass on TOC| click symbology| unique values | select “classes” from drop down

Soil Suitability Map Showing Classes

THANK YOU!