Contents
What kind of gain does Landsat 7 have?
Landsat 7 acquires thermal data in two bands from one detector in both high (Band 6H) and low (Band 6L) gain. The difference in gain settings is important to different types of studies (i.e., clouds vs. deserts).
How to convert raw Landsat data to reflectance?
The following example shows conversion from raw data to radiance and TOA reflectance for a Landsat 8 image: // Load a raw Landsat scene and display it. // Convert the raw data to radiance. // Convert the raw data to top-of-atmosphere reflectance. Conversion to surface reflectance generally requires some sort of atmospheric compensation.
How often does the Landsat satellite view the Earth?
Landsat, a joint program of the USGS and NASA, has been observing the Earth continuously from 1972 through the present day. Today the Landsat satellites image the entire Earth’s surface at a 30-meter resolution about once every two weeks, including multispectral and thermal data.
How does Google Earth Engine create Landsat composites?
For creating simple cloud-free Landsat composites, Earth Engine provides the ee.Algorithms.Landsat.simpleComposite () method. This method selects a subset of scenes at each location, converts to TOA reflectance, applies the simple cloud score and takes the median of the least cloudy pixels.
Why are there two thermal bands in Landsat 7?
Aside from the resolution differences and saturation on the high and low ends, the two bands provide the same Digital Numbers (DN) for every pixel. FILE_NAME_BAND_6_VCID_1 (band 61 or 6L) provides an expanded dynamic range and lower radiometric resolution (sensitivity), with less saturation at high Digital Number (DN) values.
How often does Landsat 7 orbit the Earth?
The Landsat 7 satellite orbits the the Earth in a sun-synchronous, near-polar orbit, at an altitude of 705 km (438 mi), inclined at 98.2 degrees, and circles the Earth every 99 minutes. The satellite has a 16-day repeat cycle with an equatorial crossing time: 10:00 a.m. +/- 15 minutes.
What kind of calibration is used on Landsat 7?
On-board calibration was added to Landsat 7: a Full Aperture Solar Calibrator (FASC) and a Partial Aperture Solar Calibrator (PASC), in addition to the 2 calibration lamps Landsat 7 data products are consistent with all Landsat standard Level-1 data products, using the specifications described on the Landsat Processing Details page.
What does HH and LL mean on Landsat?
HH = No band gain change within the scene whose gain band state was acquired in high gain mode LL = No band gain change within the scene whose gain band state was acquired in low gain mode LH = A low to high band gain change within the scene HL = A high to low band gain change within the scene
What does Landsat Collection 1 quality image do?
Landsat Collection 1 LandsatLook Quality Image: 8-bit files generated from the Landsat Level-1 Quality Band to provide a quick view of the quality of the pixels within the scene to determine if a particular scene would work best for the user’s application.
Which is higher band 62 or 6H on Landsat?
FILE_NAME_BAND_6_VCID_2 (band 62 or 6H) has higher radiometric resolution (sensitivity), although it has a more restricted dynamic range, and is more likely to saturate over hot targets. What are the _VER.jpg and _VER.txt files that are included with the Landsat MSS and TM data?