Choosing the right satellite imagery to launch your project into orbit.

  • There are a plethora of different varieties of satellites, resolutions and spectral bands to consider when deciding upon the appropriate type of imagery to support your project. 

    Each choice has its own capabilities and limitations; yet the role of TCarta is to help the end-user reach the appropriate decision; whether this is based on cost-effectiveness or programme requirement. 

    Satellite imagery is a practical and lower-cost alternative to ground surveys and LiDAR; it also adds significant value in terms of surveying a large area almost instantaneously; enabling truthful, accurate results and analysis to be quickly derived.

    This short guide below will ensure you are able to pick the right type of optical imagery to inform and expedite your programme.

    Overview: 

    There are two primary sources of optical satellite imagery in the Middle East - Maxar (formerly DigitalGlobe), and Airbus - for whom TCarta are the only accredited reseller of within the region. 

    Types of imagery available: 

    Satellite imagery can be split into two categories: Very High Resolution (VHR) and High Resolution (HR). VHR imagery typically utilises anything between 4 to 8 multispectral bands, whilst the number and type of multispectral bands for HR satellites varies depending upon the use of the specific satellite. 


    Very High Resolution Imagery
    VHR imagery is generally classed as imagery with a resolution of better than 1 metre and is available to purchase with many different options. The best approximate mapping scales that can be utilised from this imagery are shown below.

    Resolution  Approximate Mapping Scale 
    30cm 1:1,000
    40cm 1:1,000
    50cm 1:1,000

    High Resolution
    HR imagery is generally considered as imagery with a resolution above 1 metre , however still showing good enough detail to determine smaller scale features on the Earth. This consists of both freely available and commercially available options. The best approximate mapping scales that can be utilised from this imagery are shown below.

    Resolution Approximate Mapping Scale
    1.5m 1:3,000
    5m 1:10,000
    10m 1:20,000
    15m 1:30,000
    30m 1:60,000

    The number and type of multispectral bands available from the imagery TCarta has access to are listed below with some general use cases. The resolutions of each band may vary depending upon the type of satellite used to collect the imagery, and some bands are only available from specific satellites. Therefore the type of imagery required for your project will depend both on the resolution and the number and type of bands available. 

    Band  Use Case 
    Panchromatic  Black and White only. Normally the highest resolution band
    Coastal  Water penetration
    Blue Coastal applications, soil / vegetation differentiation
    Green Crop types, seagrass
    Yellow Leaf colouration, stress
    Red Vegetation analysis
    Red Edge  Vegetation health and stress
    Near Infrared  Biomass, plant stress, soil moisture, Land / Water Masking
    Short Wave Infrared  Soil conditions and crop health, fire detection, materials identification
    Thermal Infrared  Identify Sea / Land surface temperature

    This is the first in a series of blogs focusing on the properties, benefits and future developments of satellite imagery. To learn more about what TCarta can provide, please contact info@tcarta for an informal conversation. You can also follow these series of blogs on social media via TCarta's LinkedIn:https://www.linkedin.com/company/tcarta-marine.