Drone Survey and Mapping of Shaishen Foods Limited
1 Introduction
Geo-infotech Resources Limited was awarded a Drone Mapping Survey project by Shaishen Foods Limited located on the outskirts of Abeokuta. The project was carried out on the 8th of March 2023 with mobilization and was concluded on the 9th of March 2023. Image processing and analysis commenced immediately and the submission of all deliverables and the technical report was done on the 10th of March 2023. This report describes in detail the works carried out
1.1 Study Map
1.2 Site Description
The Land belonging to Shaishen Foods Limited is located on the outskirts of Abeokuta town, some 2hour drive from the main town to the site located at Apojola village Odeda LGA. Once at Odeda LGA, we had to drive for about 45minutes into the remote area where the site is located.
2.0 Deliverables
- Ortho-mosaic maps: These are highly detailed maps made from drone aerial imagery. They can be used for mapping, planning, and analysis purposes.
- Digital Elevation Models (DEMs) and Digital Terrain Models (DTMs): DEMs are topographic models of the land surface that can be generated from drone data. They are useful for visualizing and analyzing elevation and slope data.
- 3D Models: 3D models are created by stitching together multiple drone images to create a 3D representation of the land surface. They can be used for visualization, planning, and analysis purposes.
- Contour maps: These maps show the elevation of the land surface using contour lines. They can be used for visualization and analysis purposes.
- Flow direction and accumulation maps: This maps show the direction water will pass through from high to low and also where they are to be less or more accumulated in case of flooding. Production of this maps makes it easy to avoid flooding in the future.
- Slope Map: This shows the shape and relief of the land. The percent change in the elevation over a certain distance and that is what is being shown on this image.
2.1 Orthophoto
Ortho-photo Map displays many small pieces of the aerial geo-lagged photograph, mosaic together and then geometrically corrected and mapped out to its proper scale (this shows the true image of the site route)
2.2 Orthophoto 3d Map
Orthophoto 3D Map displays 3 dimensions of many small pieces of the aerial geotagged photograph, mosaic together and then geometrically connected to give a realistic representation of the area. In this study, the orthophoto presents the real world in a photographic image, it re-combines small pieces of all the aerial imagery acquired during field data acquisition duly adjusted (geo-rectified) to its actual ground position. The areas that appears green on the map are the lowland areas while the areas that appears brownish-yellow undulating land. The areas that appears white are the highland.
2.3 Beacons and Pillars
This shows how the drone team uses the already established beacons for the drone mapping, during the flight the drone picks up the beacons and this is used to geo-reference the images produced to their accurate locations on the earth
2.4 Slope
Slope identifies the steepest downhill slope for a location on a surface. This shows the shape and relief of the land. The percent change in the elevation over a certain distance and that is what is being shown on this image. Slope represents the rate of change of elevation for each digital elevation model (DEM) cell. It’s the first derivative of a DEM.
On the map the green areas are flat land with little or no steepness level as shown in the legend while the areas that are yellowish-brown are areas that very steeply as seen on the southern part of the map or site indicated with the red arrow.
2.5 Digital Surface Model
Digital Surface Model (DSM) is a digital representation of the Earth’s surface, which includes all objects and features on the surface such as buildings, trees, hills, and other structures. The DSM is typically derived from aerial or satellite imagery, and it provides a detailed 3D representation of the surface, which can be used for a variety of purposes.
In this DSM the areas that appears red indicates the presences of trees canopy and highland areas while the areas that appears blue indicates the lowland or flatland areas and the areas that appears yellow are undulating land.
Digital elevation models (DEMs) contain the elevation of a point on a surface above the mean sea level. DEMs are sometimes referred to as digital terrain model (DTM). A Digital Surface Model representsthe elevation of features on the surface modified to visualize and understand the terrain of the surface and other features within the area.
2.6 Contour Map
A contour map from the guide map showing the topography of the area with a contour level of 5-meter interval. The contour map shows the changes in elevation of the study area it allows one look at a two-dimensional map and visualizes the study area in 3-dimensions. The contour map indicates the areas of equal heights
2.7 Flow Accumulation
This shows the areas where water from the flood is mostly accumulated and where they are less accumulated. In other word area prone to be flooded during the rainy season and area prone to less flooding. The map indicates that there is low probability of flood to occur as the land is relatively a flatland the flow line indicated by the deep blue on the map are the areas where water could accumulate in the site
2.7.1 Flow Direction
This shows the analysis of slopes, from the less sloppy regions, to zones that are not sloppy, to places more sloppy, which in turn allows us know the direction water will follow so as to know areas that are more prone to flooding. This gives us the flow direction of the drainage in the site. The dark green (16) colour the indicates the flow direction to the West, the indigo colour (64) indicates the flow direction to the North, the Cyan Colour (4) indicates the flow direction to the South, the Purple colour (1) indicates the flow direction to the East, the yellow colour (128) indicates the flow direction to the North-East, the black colour (32) indicates the flow direction to the North-West and the lemon green colour(2) indicates the flow direction to the South-East.
3 Conclusions
The Drone Mapping was completed and on careful analysis of the data acquired, the results of the data processing and the maps produced, we safely came to the following conclusions:
The maps produced as a result of the drone mapping are a true and realistic representation of the subject site as the time the survey was carried out.
The mapping was carried out in full accordance with the existing specifications, survey laws and regulations and in compliance with our company quality control,
