ERA-ORA - ERS SAR data information

The image processing was made by the InSAR processor developed by the Spatial Center of Liège - CSL. The images have a pixel size of 40 by 40 meters. The signal values were extracted from a tandem pair of ERS 1/2 images acquired at the 13th and 14th of June 1996. The interferometric baseline is 94 meters. In order to keep the full information content of these images, they were neither resampled nor geometrically corrected. The digital number value (DN) correspond to the module of SLC images and were computed by the CSL using an widow size of 10X2 (azimuth X range). Moreover, during the images processing step, a normalization shift of 20 (10x2) has been applied. So, the DN value shout be divided by 20.

The selected fields have been located on a digital ortho-photography with 1-m resolution and then digitized on the co-registered images.

The data file contains the following information :

• crop_type : 4 different crop types are represented, i.e. winter wheat, sugar beet, potato and maize
• acq_date : acquisition date of images
• acq_hour : all images were acquired in descending mode, at about 10:30 GMT
• mean_DN : the digital number averaged for all the pixels included in the parcel boundaries
• sd_DN : the standard deviation of the digital number value for the considered field
• mean_coh : coherence average for all the pixels included in the parcel boundaries
• sd_coh : the standard deviation of the coherence value for the considered field
• n_pixels : the number of pixels (of 40 by 40 meters) in the field
• ca_cover : the canopy cover ratio (%) calculate using vertical color photographs of the crop taken using a 50 mm camera hold at 4-m high. This canopy cover measurement was completed by visual interpretation based on a 350-dot random sample.
• cr_height : the measured crop height (in centimeters)
• dev_state : the phenological stage
• inter_line : distance (in centimeters) between 2 rows of plants (for the winter wheat field, only the weight of sowed seeds per square meters is given instead of the inter_line and inter_plant parameters)
• inter_plant : distance (in centimeters) between 2 plants into the same row
• soil_moist : the soil moisture was measured by a gravimetric method using 6 samples per field. soil_moist gives the average of this 6 samples.
• soil_density : the average soil density measured using 6 samples per field
• 1h_rain : rainfall (in millimeters) during the satellite overpass (between 10:00 and 11:00 GMT)
• 24h_rain : 24 hours cumulative rainfall before image acquisition (in millimeters)
• 5j_rain : 5 days cumulative rainfall before image acquisition (in millimeters)

The data were provided by:

The Department of Environmental Science and Land use planning – geomatic

Université Catholique de Louvain

Pr. P Defourny

Croix du sud 2/16

B-1348 Louvain-la-Neuve

Phone : +32 10 47 23 74

Fax : + 32 10 47 88 98