=> Land cover and land use maps Although different, the terms land use and land cover are often used as synonymous. From Wikipedia Land cover is the physical material at the surface of the earth. Land covers include grass, asphalt, trees, bare ground, water, etc. There are two primary methods for capturing information on land […]
=> The end of SPOT4 (Take5) experiment was initially planned the 28th of May, but CNES just decided to extend it until the end of Spring. The last SPOT4 images should be acquired around June the 21st. In France, and in many other countries, June 21st is the « Music Day » : we will be playing […]
Non, nous n’avons pas encore décidé de financer nos travaux par la publicité… Il s’agit simplement de vous rappeler que la communication est une part importante du projet SPOT4 (Take5), afin de montrer tout l’intérêt des séries temporelles. Ce blog peut non seulement présenter les excellents (hum) résultats, côté CNES et CESBIO, mais aussi les […]
=> Earth surface observations by space-borne optical instruments are disrupted by the atmosphere. Two atmospheric effects combine to alter the images : Here are two SPOT4 (Take5) images, acquired with a time gap of 5 days above Morocco. Because of atmospheric effects, the second image has less contrast and is « hazier » than the first one. […]
LANDSAT 8 first Image was just issued. Here at CESBIO, we are very happy to see that everything seems to be working and we are already looking forward to routine acquisitions.Congratulations to NASA and USGS Teams !
=> We have now received all the L1A images of the SPOT4(Take5) experiment taken between January the 31st and March the 10th, for which at least some part of the surface is visible. We ortho-rectify these images to obtain level 1C products, but sometimes, the cloud cover is still too high to process the image. […]
=> Now that you know almost everything on our cloud detection method and on our shadow detection method, we can show you the first results obtained by Mireille Huc (CESBIO) with SPOT4(Take5) time series. As the method is multi-temporal, it needs an initialisation phase, and we had to wait until we had a sufficient number […]
=> The cloud shadows are dark and, of course, they are due the presence of a nearby cloud. Apart from these facts, there is not much information to detect clouds, and for this reason, the cloud shadows are even more difficult to detect than the clouds themselves. The shadows are not the only dark objects, […]
=> Clouds are white, bright, rather high in the sky. Their temperature is generally lower than that of the surface. They move and change appearance, and they cast shadows on the ground. All these properties can be used to automatically detect clouds. Standard detection The basic technique consists in thresholding the image of a spectral […]