Q2: Remote sensing has been widely used in many application and industry sector. Discuss every platform of remote sensing can benefit the agriculture industry related to temporal and resolution factor.

Satellite platform

The satellite platform is the most common remote sensing system that people know. The satellite is a vehicle that carry the payload (sensor) and place on the orbit. There so many type of orbit for satellite. Most remote sensing satellite use Low Earth Orbit (LEO). Type of satellite remote sensing such as Landsat-TM, SPOT, IKONOS, Quickbird and many other else. These satellite carry the sensor (camera) that scan and capture the imagery of the earth surface. Most of remote sensing satellite carry the multispectral sensor covering from visible light spectrum (Red, Green & Blue) and near infra-red (NIR) spectrum. The satellite can capture the image of the earth surface in large area. For example, SPOT satellite can capture the earth surface imagery in 60sqkm in a single time with 5-meter spatial resolution. The spectral resolution of SPOT satellite is covering from visible light and near infra-red spectrum make it useful for vegetation and agriculture study. The revisit time for SPOT satellite is within 2 or 3 days depending on latitude of the orbit. The keys of vegetation and agriculture crop study using remote sensing data is Vegetation Indices (VI).

There is so many research done in vegetation and agriculture study base on VI. The agriculture study can be done using SPOT satellite for huge crop area such as oil palm, rubber, soybean, corn and grain due to capability of the satellite to carry multispectral resolution sensor. However, the agriculture study using satellite image cannot be a very detail up to individual crop due to spatial resolution limits. And also, due to cloud cover contamination especially in Malaysia region. The temporal resolution or revisit time are also limit the analysis of crop monitoring study especially for short term crop planting like paddy, corn and other.

Aircraft platform (airborne & drone)

Nowadays, the optical sensor technology has evolved from big DSLR camera to small digital camera that can be attach on the small aircraft or remote control aircraft. Using drone as a platform to carry the sensor is now widely use in the agriculture industry. The drone can be program and set to fly above the crop field based on coordinate given to the drone autopilot. Most of the drone can fly around 30-45 minute and covering the small crop area around 30-40 hectares’ subject to altitude of the drone fly. Most of the drone imagery can give a very good spatial resolution compare to satellite platform. With a very sharp imagery capture by drone, it is really suitable to do the vegetation study and agriculture crop monitoring. Since the imagery is very sharp, we can identify and analyse every single crop (subject to type of crop) for example is oil palm. Also, the drone imagery is not limited to cloud cover. The farmer can identify the single oil palm tree using drone imagery. Other benefit using drone, we can rapidly monitor the crop growing stages and study the crop physiology using multispectral sensor.

Terrestrial remote sensing platform.

Terrestrial remote sensing platform is most unknown remote sensing technology. Not many people realise that some device such as Green Seeker is one of the remote sensing tool. The green seeker tool is use to identify the individual crop manually on the ground. It is very useful device to identify the disease and crop healthy. The green seeker device is attach with Red and Near Infra-Red (NIR) sensor to measure the amount of reflectance from Red spectrum and NIR spectrum. This reading of reflectance is used to measure the vegetation indices from the crop leaves. The measurement can directly be made using green seeker device. The farmer can directly know current condition of their crop either enough nutrient or not, and healthy and infected by disease. However, the challenge using this device, the farmer has manually scan the crop individually in the field. To do the manually checking using this device would is not applicable for huge area of crop and will increase the cost for labour and time consuming. Mostly, this device can only be used as a references or baseline to compare the result of study using drone imagery or satellite imagery.

There is an algorithm and relationship between the measurement of vegetation indices (VI) value from green seeker device and drone or satellite imagery vegetation indices (VI). This analysis can be done using spatial variable analysis in precision agriculture study. In Europe country, the sensor is attach to the farm tractor to monitor the crop status rapidly during the growing stage in order to maximize the crop yield. This sensor is also functioning as green seeker device. It measures the vegetation indices value of the crop and give the direct result to the farmer about the condition of the crop.