=Paper=
{{Paper
|id=Vol-1498/HAICTA_2015_paper46
|storemode=property
|title=Precision Agriculture – Comparison and Evaluation of Innovative Very High Resolution (UAV) and LandSat Data
|pdfUrl=https://ceur-ws.org/Vol-1498/HAICTA_2015_paper46.pdf
|volume=Vol-1498
|dblpUrl=https://dblp.org/rec/conf/haicta/KavvadiasPCGM15
}}
==Precision Agriculture – Comparison and Evaluation of Innovative Very High Resolution (UAV) and LandSat Data==
https://ceur-ws.org/Vol-1498/HAICTA_2015_paper46.pdf
Precision Agriculture – Comparison and Evaluation of
Innovative Very High Resolution (UAV) and LandSat
Data
Antonis Kavvadias1, Emmanouil Psomiadis2, Maroulio Chanioti3, Eleni Gala1,
Spyros Michas1
1
En Agris LLC, Evias 3 15125, Maroussi, Greece, e-mail: info@enagris.gr
2
Agricultural University of Athens, Laboratory of Mineralogy & Geology, Iera Odos 75, 118
55, Athens, Greece, e-mail: mpsomiadis@aua.gr
3
Inforest Research o.c, Glaraki 10B, 11145, Αthens, Greece, e-mail: mchanioti@inforest.gr
Abstract. The Precision Agriculture primarily involves the use of geospatial
technology to map the spatial changes in plant and soil conditions of crops and
their correlation with agricultural inputs such as water, fertilizer, etc., at a
spatial basis. For the present study, the UAV eBee of SenseFly SA was used,
in order to demonstrate the utility and effectiveness of these new airborne
instruments in the observation of crops. Also, the corresponding free data of
the satellite Landsat-8 was used for the comparison. As study area the crop
fields of the Agricultural University of Athens in Aliartos, Viotia were chosen.
The NDVI (Normalized Difference Vegetation Index) given from the UAV
and the Satellite was calculated separately by two different Softwares. A
comparison and evaluation of the indicators of the two Remote Sensing means
carried out, in order to examine the effectiveness of the data received from the
UAV camera.
Keywords: Precision Agriculture, UAV, LandSat-8, NDVI
1 Introduction
A few years ago the use of UAVs was not that widespread. In the last decade,
however, there was a rapid evolution of technology led to the creation of more
sophisticated UAVs. The improved cameras that can carry, offer information in the
Visible, Near-Infrared and Thermal part of the electromagnetic spectrum and the
improved software of processing of images have led to the increasing use of the
UAVs in Precision Agriculture (Xiang & Tian 2011, Mesas-Carrascosa et al. 2014,
Torres-Sánchez et al. 2014, Rokhmana 2015).
In this study the UAV eBee of SenseFly SA and the camera Canon S110 NIR
were used. The Canon S110 NIR takes images in Visible-Green, Visible-Red and
Near-Infrared part of the electromagnetic spectrum.
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As study area was chosen the area of Aliartos, which belongs to the Agricultural
University of Athens and includes an agricultural land of 110 hectares, with wheats,
oats, alfalfa and fallow or uncultivated land (Figure 1).
Also, the choice of OLI receiver data was performed because the Landsat satellite
system constitutes one of the most tested, designed and reliable satellite systems,
even though the spatial resolution of 30m which provides is not fully considered
satisfactory for pixel to pixel comparison with the UAV sensor. Therefore an attempt
was made to compare the tendency of change of important vegetation indices such as
NDVI. The two recording systems of the Landsat-8 satellite and the UAV provide
recordings in the red and near infrared range of the electromagnetic radiation so that
it is possible to calculate the NDVI index.
Fig. 1. The crops of the Agricultural University of Athens in Aliartos, Viotia, Greece Google
Earth image
2 Data
Normalized Difference Vegetation Index (NDVI)
Estimation of:
- General plant health condition
- Photosynthetic activity
- Possible deficiency of nutrients
(1)
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2.1 Satellite Images: Landsat-8 (OLI)
Fig. 2. Landsat-8 image of NDVI, Aliartos, 14/01/2015
Fig. 3. The quicklooks of the Satellite images of Landsat-8 that were used
Table 1. The spectral bands of LandSat-8 that were used
Band Wave Length Resolution
(micrometers) (meters)
Band 4 – Red 0.64 - 0.67 30
Band 5 - Near Infrared (NIR) 0.85 - 0.88 30
Band 8 – Panchromatic 0.50 - 0.68 15
2.2 UAV Images: EBee (Canon S110 NIR)
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Platform: eBee
Gross Weight: 0.69 Kg
Wingspan: 96 cm
Max Flight Time: 45 min
Radio Link Range: 3 Km
Fig. 4. UAV Ebee
Sensor: Canon S110 NIR
Resolution: 12 ΜPixel
Bands:
• Green (G)
• Red (R)
• Near-infrared (NIR)
Fig. 5. The spectral ranges that the sensor Canon S110 NIR covers
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Fig. 6. Wheat and Alfalfa crops, Aliartos. NIR image sample of eBee (Canon S110 NIR)
3 Methods
3.1 Landsat-8
! Geometric Correction
! Atmospheric Correction (ENVI, version 5.2)
• Top of Atmosphere reflectance (ΤοΑ Reflectance)
Reflectance in the atmosphere
• FLAASH (Fast Line-of-sight Atmospheric Analysis of Spectral
Hypercubes)
Reflectance on the ground
! Panchromatic sharpening
(ΝΝDiffuse PanSharpening, ENVI)
• Panchromatic (Res: 15m)
• Spectral Bands (Res: 30m " 15m)
! NDVI export (Res: 15m) (Fig. 7)
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Fig. 7. Geometrically and Atmospherically corrected LandSat-8 image (Grayscale). Aliartos,
14/01/2015
3.2 UAV eBee
! Flight Plans (eMotion, SenseFly)
• Image Resolution: 11cm/px
• Lateral Overlap: 65%
• Longitudinal Overlap: 80%
Flights
• Flight Duration: 25΄
• Flight Height: 315m
Image Post-process (PostflightTerra 3D, Pix4D)
• Orthomosaic production
• Reflectance Map production
• NDVI map production
Fig. 8. UAV flight control monitor
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Fig. 9. Reflectance map of eBee. Aliartos, 14/01/2015
Fig. 10. NDVI Orthomosaic. Aliartos, 14/01/2015. Platform: eBee
Fig. 11. NDVI Orthomosaic. Aliartos, 19/03/2015. Platform: eBee
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4 Results – Discussion
The comparison of the NDVI values provided for the two periods (January and
March) for each observation instrument (eBee and Landsat-8) carried out. Therefore
we created a fishnet of values in such a way as to include any type of crop field. So
the points 1-2-5 were selected in bare ground, the points 0-3-6 in fields that were
sown in January and were grown in March (Soft wheat, Durum wheat and oats) and
the points 4-7-8 in fields with different vegetation growth in each period (Alfalfa).
The NDVI values of the images were exported and reflected in a diagram for each
period to a comparison of the trend of values for each observation instrument
(Figure 13a and 13b). The comparison of the values in the diagrams showed a very
good identification of the distribution (tendency) of the values for the two means of
observation in both periods. Small deviations in some points, such as at point 0 in the
diagram of January, are possibly due to the difference of spatial resolution between
the images.
Also, in order to verify the given identification of the NDVI values between the
two means of observation, a spatial profile of a linear section was created (Figure
14), so as to include, as many as possible different forms of vegetation; from bare
soil to fields covered by full vegetation. The comparison of spatial profiles gave the
same results to the charts and confirmed the very good identification of the
distribution (tendency) of the values of the two means of observation in both periods
(Figure 15).
4.1 Comparison of the tendency of NDVI values of the eBee & Landsat-8 for
14/01/2015 & 19/03/2015
4.1.1 Fishnet creation (0-8)
Fig. 12. The fishnet of selected points in the 4 maps; (i) eBee - January, (ii) Landsat_8 -
January, (iii) eBee - March, and (iv) Landsat_8 – March
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Table 2. The spectral bands of LandSat-8 that were used
Point Cultivation
0 Durum Wheat
1 Bare Soil
2 Bare Soil
3 Oats
4 Alfalfa
5 Bare Soil
6 Soft Wheat
7 Alfalfa
8 Alfalfa
Fig. 13a. The NDVI values distribution of January, for the two means of observation
Fig. 13b. The NDVI values distribution of March, for the two means of observation
384
4.1.2 Linear section creation and spatial profile production for the NDVI maps
Fig. 14. The linear section (red line) that was chosen to create the spatial profile of the NDVI
maps.
Fig. 15. The spatial profile of the linear section for the eBee (i, ii) and Landsat-8 (iii, iv)
images for the January and March
5 Conclusion
The results of comparing the NDVI values of the two earth observation data have
shown that there is a fairly good coincidence of the value variation between them,
which demonstrates the excellent quality of the UAV data, while highlighting the
usefulness for wider and more systematic use in Precision Agriculture. The UAVs as
they offer a better spatial and temporal resolution, a higher speed and a lower cost,
may offer more direct and easier solutions in agricultural production. Of course it is
necessary and is a goal of further consideration in the near future, the comparison of
the UAV with a remote sensing observational mean of a similar spatial resolution as
well.
385
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