Georeferencing Instructions

1. Identifying georeferencing points

• In the png map identify 4 points that can be used easily to georeference
• Note down the X and Y coordinates for each identified point
• Note if the units are in meters or in feet. See the example below

Point	X	Y
A	6750	-115750
B	9000	-115750
C	8750	-117250
D	9000	-117250

The raster's Y coordinates in this example are negative because the location is South of the equator. The raster's X coordinates in this example are positive because they are East of the Greenwich Meridian.

2. Converting coordinates

• Use the following website to convert coordinates from cassini to either UTM (WGS84), GCS (WGS84) or Arc 1960. Shambamap used WGS84 4326
• However this website is only fit for land parcels in Nairobi, Kiambu and part of Kajiado and Machakos.
• See the screenshot attached below
• Be keen to ensure that the coordinate units (the current map is in meters) are correctly selected before you start the conversion process

3. Georeferencing process in QGIS

• In QGIS click on Layer tab and select Georeferencer.
• Upload the map in png format that you want to georeference.
• Create 4 georeferencing points from the earlier identified points and enter the converted coordinates. Ensure that you select the correct coordinate system in line with the converted coordinates
• Run the georeferencing process by clicking on the run (play) button. Save the output tiff (image) to your desired location and ensure the output coordinate system (WGS84 4326) is correct
• The georeferenced image is automatically added to QGIS
• Verify by overlaying on Google Satellite to see if the image was correctly georeferenced
• The following video shows all the steps followed in QGIS to georeference the map