The optical imagery obtained from imagery satellite LANDSAT-7 ETM+ has been used in a variety of sectors including governmental, educational and commercial applications. Launching in April 15, 1999, LANDSAT-7 has provided over 16 years' worth of satellite imagery which has been extensively used for long-term land use change detection. Its multispectral sensor provides imagery with a Ground. . The Landsat satellites were designed to be of use to a variety of fields like forestry, agriculture, geology, and land-use planning, and the choice of spectral bands for the Landsat satellites was geared toward discriminating different types and.
124 Landsat-7 ETM+ (Irons et al. 2012). The OLI dynamic range is improved, reducing band 125 saturation over highly reflective surfaces, and the greater 12-bit quantization permits improved measurement of subtle variability in surface conditions (Roy et al. 2014a).126 The Landsat-7 ETM ランドサット7号 (Landsat 7) は、1999年4月15日に打ち上げられたランドサット計画の人工衛星である。 ランドサット7号の主目的は、地球を撮影した衛星写真の更新であり、最新の雲のない画像を撮影することであった。 ランドサット計画は、アメリカ地質調査所 (USGS) が監理運営しており、撮影.
Explanation of the problem: On 31 May 2003 the Landsat 7 Enhanced Thematic Mapper (ETM+) sensor had a failure of the Scan Line Corrector (SLC). Since that time all Landsat ETM+ images have had wedge-shaped gaps on both sides of each scene, resulting in approximately 22% data loss How is LANDSAT 7 abbreviated? L-7 stands for LANDSAT 7. L-7 is defined as LANDSAT 7 frequently Landsat 7 is the Enhanced Thematic Mapper Plus (ETM+). ETM+ is a passive sensor that measures solar radiation that is either reflected or emitted Landsat Collections Tiers. Landsat Collections consist of three tiered categories: Real-Time, Tier 1, and Tier 2. The Real-Time (RT) tier contains . data received from Landsat 8 and Landsat 7 immediately after acquisition. Estimated radiometric and geometric calibration parameters are applied to these scenes, which are made avail
I am currently working with Landsat 7 ETM+ data for a school project and I have to fill the gaps in the images before further processing. I read somewhere that it is possible to download an ENVI gap fill extension and use this .sav file to fill the gaps in the software, but I somehow don't find the link to download this extension These are Landsat 7 values and may be the same or vary for other Landsat 7 scenes, so it is recommended to do this on an image by image basis. Landsat 5 values are different than Landsat 7. EARTH_SUN_DISTANCE = 1.0162916 (older Landsat 5 or 7 may not have this value in the MTL file; if not access this document [PDF on this website] to find the. The Landsat 7 Enhanced Thematic Mapper Plus (ETM+) scan line corrector (SLC) failed on May 31, 2003, causing the scanning pattern to exhibit wedge-shaped scan-to-scan gaps. The ETM+ has continued to acquire data with the SLC powered off, leading to images that are missing approximately 22 percent of the normal scene area. To improv Landsat 7 was a copy of Landsat 6, but by the time it was ready for launch the program had been transferred back to NASA who launched it on April 15, 1999. The value of the Landsat program was recognized by Congress in October, 1992 when it passed the Land Remote Sensing Policy Act (Public Law 102-555) authorizing the procurement of Landsat 7. The S/C and payload were developed under NASA/GSFC management/procurement responsibility (Landsat Project Scientist: D. Williams). The LS-7 satellite was built by LMMS (Lockheed Martin Missiles and Space) at the facility in Valley Forge, PA. The S/C features the Landsat-6 bus; an onboard recorder in solid state memory (378 Gbit capacity to capture data beyond the range of ground receiving stations, recording rates of 150 Mbit/s, playback with 300 Mbit/s), and a single observation instrument: ETM+. 2) 3)
Here I will give a basic work flow for visualizing Landsat-7 ETM+ image data, from the USGS, in QGIS. The version of QGIS this is based on is the Windows v. 1.6.0 Capiapo installation. The data are a Landsat-7 ETM+ image dataset, downloaded from the United States Geological Survey using their GLOVIS service. The image .The Landsat mission provides the longest continuous space-based record of Earth's land, dating back to 1972 and the Landsat 1 satellite The principal functional differences between the ETM and the former TM series are the addition of a 15 m resolution panchromatic band and two 8-bit “gain” ranges. The ETM+ adds a 60 m resolution thermal band, replacing the 120 m band on ETM/TM (band No. 6). Design life = 7 years. 5) Landsat 7 is still collecting data. Landsat 8 orbits at the same altitude as Landsat 7. Both satellites complete an orbit in 99 minutes, and complete close to 14 orbits per day. This results in every point on Earth being crossed every 16 days. But, because the orbits of the two satellites are offset, it results in repeat coverage every 8 days.
The thermal infrared band from Landsat 7 is now split into two bands for Landsat 8. Whereas before you had one thermal band that was acquired at 60 m resolution (and resampled to 30 m) now you have increased spectral resolution at the cost of spatial resolution “Those are the Islands of the Four Mountains… The Landsat image shows them on June 8, 2013… One of the things I love about science is how it gives us perspective.”
The LandsatLook Viewer is a prototype tool that was developed to allow rapid online viewing and access to the USGS Landsat image archives. This viewer allows you to: Interactively explore the Landsat archive at up to full resolution directly from a common Web browser. Search for specific Landsat images based on area of interest, acquisition. The Landsat Thematic Mapper (TM) sensor was carried on Landsat 4 and Landsat 5, and created images consisting of six spectral bands with a spatial resolution of 30 meters for Bands 1-5 and 7, and one thermal band (Band 6). The approximate scene size is 170 km north-south and 183 km east-west (106 mi by 114 mi)
EarthNow! displays near-real time imagery of Landsat 7 and Landsat 8 data being collected by USGS as the satellites cross over the Earth. Along with live stream video, the tool also replays image loops from a list of recent overpass recordings. To learn more about each Landsat satellite, sensors, bands, and years of operation, please visit the Landsat Missions website Landsat 9. Landsat 9 is a partnership between the National Aeronautics and Space Administration (NASA) and the U.S. Geological Survey (USGS) that will continue the Landsat program's critical role of repeat global observations for monitoring, understanding, and managing Earth's natural resources “There are roughly 400 billion land pixels in a single [Landsat] global mosaic.” (With at least one image of every location on Earth per season every year, the entire 43-year Landsat record contains more than 50 trillion pixels.)
LANDSAT 7 satellite is equipped with Enhanced Thematic Mapper Plus (ETM+), the successor of TM. The observation bands are essentially the same seven bands as TM, and the newly added panchromatic band 8, with a high resolution of 15m was added Looking for online definition of LANDSAT or what LANDSAT stands for? LANDSAT is listed in the World's largest and most authoritative dictionary database of abbreviations and acronyms The Free Dictionar .pix) file using the key file name. For optimal processing, use the PCIDSK format. The data structure, after it is opened by GDB, is as described in the following table
Landsat 7 delivers ca. every 2 weeks new scenes from most locations in the world. On demand we provide up-to-date scenes SLC-Off corrected and color-enhanced. Here you can browse a SLC-off patched mosaic of Libya 2009 Media in category Landsat 7 The following 12 files are in this category, out of 12 total Ground sites exist at Sioux Falls, South Dakota (Landsat Ground Station, or LGS), Poker Flat, Alaska (Alaska Ground Station, or AGS), Wallops Virginia (WPS), and Svalbard, Norway (SGS). All ground sites are equipped with 11 meter antennas. AGS, SGS, and LGS are capable of receiving both S-band (TT&C) at a downlink rate of 4 kbit/s and X-band (payload) data simultaneously. I see some scholars only have used band 10 of Landsat 8 and band 6.1 of Landsat 7 for estimation LST ; while some other scholars have used the mean value of bands 10&11 of landsat 8 and mean. The latest mission in the Landsat series—Landsat 7—continues the flow of global change information to users worldwide. Scientists use Landsat satellites to gather remotely sensed images of the land surface and surrounding coastal regions for global change research, regional environmental change studies and other civil and commercial purposes
Landsat 7 continued the long-term Earth observation Landsat program begun in 1972. Landsat 7 was a joint project between NASA, NOAA, and the US Geological Survey to obtain continuous high-resolution imagary of the earth's surface for environmental monitoring, disaster assessment, land use and regional planning, cartography, range management. To narrow your search area: type in an address or place name, enter coordinates or click the map to define your search area (for advanced map tools, view the help documentation ), and/or choose a date range. Search Limits: The search result limit is 100 records; select a Country, Feature Class, and/or Feature Type to reduce your chances of. At an altitude of 705 km, a full surface scan by Landsat 7 takes 232 turns, or 16 days. The terrain survey takes place at approximately 10 am (± 15 minutes) according to local solar time.The ETM instrument incorporates a new 15 m panchromatic band, as well as a 9-bit analog to digital converter. The panchromatic band was added to provide higher spatial landsat 7 resolution observations, as a compliment to the 30 m multispectral measurements. In order to limit the telemetered data stream to a reasonable volume, a 9-bit A-to-D system was designed so that either the upper or lower 8 bits of the radiometry could be provided from the system. This introduces the potential for two gain states (high and low), which, particularly for dark landscapes, could increase the radiometric signal.
Preprocessed Landsat-7 data for North Carolina. The North Carolina 2008 sample dataset comes with 3 different Landsat scenes: (Wake County -- path: 16 row: 35 for various dates) The above import efforts are not needed since the data are already in a GRASS location. Landsat-5: Oct 14, 1987 Glovis download LT50160351987287XXX0 In 1999, Landsat 7 began its mission with a new sensor, the Enhanced Thematic Mapper Plus (ETM+). Multi-Spectral Scanner. The Multi-spectral scanner (MSS) is a sensor that was carried on the first 6 Landsat satellites. It produces images of the Earth that cover an area of about 34,000 square kilometers (about 13,000 square miles) with a. NASA's Visible Earth catalog of NASA images and animations of our home plane Landsat 8 captures about 400 images of the Earth each day, far more than the 250 a day of Landsat 7. As it orbits the Earth in a north-south pattern, Landsat 8 collects images from a swath about 115 miles (185 km) across, using a push broom sensor, which captures data from the entire swatch at the same time
. The spacecraft was derived from the Tiros-N/DMSP weather satellites Landsat 8 and Landsat 7 comparison, First Look by Santosh Singh Landsat Data Continuity Mission or Landsat 8 has been long awaited since the failure of the Scan Line Corrector onboard the Landsat ETM+ satellite sensor, just 4 years after its launch in 1999 4) K. Dolan, P. Sabelhaus, D. Williams, “Landsat-7 Extending 25 Years of Global Coverage,” Proceedings of Information for Sustainability, 27th International Symposium on Remote Sensing of Environment, Tromsoe, Norway, June 8-12, 1998, pp. 622-625 Landsat 7 mission but focuses on the information needed by the users to gain an understanding of the science data products. This handbook includes various sections that provide an overview of reference materia
Landsat 7 gains have been continuously monitored using PICS trending since the launch of the instrument in 1999. Unlike Landsat 5, Landsat 7 has been very stable long term. But, PICS trending for over 10 years did reveal a consistent, but small, trend that was statistically significant. Table 5 gives the results for gain trending Landsat 7 with. “The Landsat archive holds great potential for studying the processes behind the Greenland Ice Sheet’s response to our changing climate over multi-decadal time scales. It is essential that this record be exploited over other areas of the Greenland Ice Sheet.” The Landsat Enhanced Thematic Mapper Plus (ETM+) was introduced with Landsat 7 and was built by Raytheon SBRS (Santa Barbara Remote Sensing), Goleta, CA. ETM+ is an 8-band whiskbroom scanning radiometer consisting of: A primary mirror that sweeps side-to-side (across-track) to produce forward and reverse image scans, an
The Landsat 7 ETM+ instrument is designed with the significant exception of the thermal infrared band, where the ground resolution has been improved from 120 to 60 m. The ETM instrument incorporates a new 15 m panchromatic band, as well as a 9-bit analog to digital converter The Landsat 1 also has the distinction of being the first civilian Earth observation satellite. Since the first satellite launched on July 23, 1972, the Landsat Program has developed eight different satellites, the two most recent being the Landsat 7 in 1999 and Landsat 8 in 2013. Both are still operational Landsat 8 is an American Earth observation satellite launched on February 11, 2013. It is the eighth satellite in the Landsat program; the seventh to reach orbit successfully. Originally called the Landsat Data Continuity Mission (LDCM), it is a collaboration between NASA and the United States Geological Survey (USGS). NASA Goddard Space Flight Center in Greenbelt, Maryland, provided.
Benefits of Landsat 8. Scientists from NASA and the USGS hope that the images from the Landsat 8 will have several benefits. The picture of the Fort Collins area showing the burned area from the Galena wildfire could help Burned Area Response teams manage wildfire recovery efforts while the ability to measure different surface temperatures could be beneficial for water management, especially. LANDSAT 7. Track LANDSAT 7 now! 10-day predictions LANDSAT 7 is classified as: Earth resources. NORAD ID: 25682 Int'l Code: 1999-020A Perigee: 708.6 km Apogee: 710.3 km Inclination: 98.1 ° Period: 98.8 minutes Semi major axis: 7080 km RCS: 4.7002 m 2 (large) Launch date: April 15, 1999 Source: United States (US) Launch site: AIR FORCE WESTERN TEST RANGE (AFWTR) LANDSAT 7 was a joint project.
17) T. Arvidson, S. Goward, J. Gasch, D. Williams, “Landsat-7 Long-Term Acquisition Plan: Development and Validation,” PE&RS, Vol. 72, Oct. 2006, pp. 1137-1146 7 = Landsat satellite #7 8 = Landsat satellite #8 9 = Landsat satellite #9 Scan Gap Interpolation. Field Definition: Maximum scan gap width (in units of ETM+ 30-m detectors/pixels) filled by interpolation. Scan Line Corrector. Field Definition: All Landsat 7 scenes collected since May 30, 2003 have data gaps due to the Scan Line Corrector (SLC. LANDSAT 7 Satellite Imagery (1999-2003) I 0 50 100. oe HVMVII bBOeBVVN HVMVII . Created Date: 20130711155809-1 The band names are in line with Landsat 8 bands; GLS data band names are mapped along the same lines. Name: Landsat/MS Description: Multispectral Landsat image service covering the landmass of the World. This service includes scenes from Landsat 8 and Global Land Survey (GLS) data from epochs 1990, 2000, 2005 and 2010 at 30 meter resolution as. Download the data by clicking the Download button. If you are going to performing analysis on the Landsat data, the Level 1 GeoTIFF data product is probably the one you're after, which will be the largest file size. The USGS Earth Explorer gives a quick and intuitive way to download free aerial and satellite imagery. This tool gives a.
An unprecedented enterprise began 40 years ago when the Earth Resources Technology Satellite—later renamed Landsat—was launched. Five more Landsat spacecraft would reach orbit during the next 27 years. All were launched from Vandenberg Air Force Base, Calif. into near-polar orbits, allowing them to image the entire Earth, one slice at a time, as it rotated below, and Lockheed Martin built. The Landsat satellite record stretches from 1972 to the present. This gallery includes all Landsat images published on the Earth Observatory, Visible Earth, and Landsat Science web sites from all seven Landsat satellites (Landsats 1-8, Landsat 6 failed to achieve orbit). All of the images are in the public domain and may be used with attribution Involving three large American governmental organizations: NASA, NOAA and USGS launched on April 15, 1999. Landsat 7 is equipped with ETM+ (Enhanced Thematic Mapper Plus), which provides a ground survey in four modes: VNIR (Visible and Near Infrared), SWIR (Shortwave Infrared), PAN (Panchromatic - Panchromatic range), TIR (Thermal infrared - Thermal infrared range). Landsat 7 Item Preview landsat7-230034_thumb.jpg . remove-circle Share or Embed This Item. EMBED. EMBED (for wordpress.com hosted blogs and archive.org item <description> tags) Want more? Advanced embedding details, examples, and help! No_Favorite. share.
Determining Landsat 8 overpass times. Each day the path numbers increment by 7 so keeping that in mind you should be able to find an overpass date for your path without too much trouble. For example, on August 1, 2013 Landsat 8 will acquire image along path 9 so the next day I know that it will acquire images over pass 16. If that's too. An ongoing collection of satellite imagery of all land on Earth produced by the Landsat 8 satellite. Update Frequency. New Landsat 8 scenes are added regularly as soon as they are available. There are no restrictions on the use of data received from the U.S. Geological Survey's Earth Resources Observation and Science (EROS) Center or NASA's.
I am using Landsat 7 to calculate land surface derived temperature. I understand the main concepts behind the conversion, however, I am confused on how to factor Emissivity into my model. I am using the model builder for my calculations and have created several modules that uses the instruments Gain, Bias Offset, Landsat K1, and Landsat K2. Launched on February 11, 2013, Landsat 8 (formerly the Landsat Data Continuity Mission, LDCM) is the future of Landsat satellites. It is collecting valuable data and imagery to be used in agriculture, education, business, science, and government. The Landsat Program provides repetitive acquisition of high resolution multispectral data of the Earth's surface on a global basis
Landsat-7 data is received and distributed to the user community by USGS (capturing and processing 250 Landsat scenes per day and delivering at least 100 of the scenes to users each day).NASA/GSFC performed on-orbit mission operations until Oct. 1, 2000; after that responsibility for flight operations and LS-7 management was transferred to the. The Landsat 7 and Landsat 8 satellites both orbit the Earth . at an altitude of 705 kilometers (438 miles) in a 185-kilometer (115-mile) swath, moving from north to south over the sunlit side of the Earth in a sun synchronous orbit. Each satellite makes a complete orbit every 99 minutes, completes about 14 full orbit
Landsat Collection 1 consists of Level-1 data products generated from Landsat 8 Operational Land Imager (OLI)/Thermal Infrared Sensor (TIRS), Landsat 7 Enhanced Thematic Mapper Plus (ETM+), Landsat 4-5 Thematic Mapper (TM)*, and Landsat 1-5 Multispectral Scanner (MSS) instruments “You may have heard me say this before, but I firmly believe there are few topics more fundamental to study than the workings of our planet. The earth sciences aim to unravel how the lithosphere, atmosphere, hydrosphere, and biosphere operate—and how they operate together. It is a science of synthesis. And it’s one that needs to move forward, both because of the great service the earth sciences perform for society and the understanding of world-shaping pro…
Aerial imagery service. Compared to other imagery (e.g. Bing), Landsat is lower resolution, but it can still be useful for tracing large features, eg forests, lakes or coastlines. Landsat images can be viewed in JOSM using the WMS/TMS imagery feature. As default, this came configured with this URL for Landsat, provided by the former Jet Propulsion Laboratory (JPL) 13) G. Chander, D. J. Meyer, D. L. Helder, “Cross Calibration of the Landsat-7 ETM+ and EO-1 ALI Sensor;” IEEE Transactions on Geoscience and Remote sensing, Vol. 42, No 12, Dec. 2004, pp. 2821-2831
Landsat 7 carries the Enhanced Thematic Mapper Plus (ETM+) sensor, an improved version of the Thematic Mapper instruments that were onboard Landsat 4 and Landsat 5. Landsat 7 products are delivered as 8-bit images with 256 grey levels. Descriptions of Landsat 7 band designations and comparisons of all Landsat sensors are available Spacecraft controllers immediately suspended normal LS-7 operations and limited activity to just spacecraft housekeeping and operations related to the anomaly investigation and recovery effort. However, subsequent efforts to recover the SLC were not successful and the problem appears to be permanent. Without an operating SLC, the ETM+ line of sight now traces a zig-zag pattern along the satellite ground track (Figure 10). The resulting gaps in coverage range from none at the center of the scan to 14 pixels at the extreme edges of the scan. Landsat 8 OLI/TIRS C1 Level-1 . 0. OrbView-
Landsat 7 acquires data in descending (daytime) node, while Landsat 8 acquires data in both descending and occasional ascending (nighttime) node. Row refers to the latitudinal center line of a frame of imagery. As the satellite moves along its path, the observatory instruments are continuously scanning the terrain below. These will be squares. Landsat 7 Enhanced Thematic Mapper Plus Collection 1 Level-1 - Metadata Updated: March 7, 2020. The USGS Earth Resources Observation and Science (EROS) Center archive holds data collected by the Landsat suite of satellites, beginning with Landsat 1 in 1972. All Landsat data held in the USGS EROS archive are available for download at no charge Landsat 7 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 Landsat Remote Sensing tif Files in R. In this lesson you will cover the basics of using Landsat 7 and 8 in R. You will learn how to import Landsat data stored in .tif format - where each .tif file represents a single band rather than a stack of bands. Finally you will plot the data using various 3 band combinations including RGB and color. Abstract: The Landsat Enhanced Thematic Mapper Plus (ETM+) is a sensor carried onboard the Landsat 7 satellite and has acquired images of the Earth nearly continuously since July 1999, with a 16-day repeat cycle. Landsat ETM+ image data consist of eight spectral bands (band designations), with a spatial resolution of 30 meters for bands 1 to 5.
Landsat synonyms, Landsat pronunciation, Landsat translation, English dictionary definition of Landsat. n. Any of various satellites operated by US government organizations, used to gather data for constructing images of the earth's surface ดาวเทียม landsat-7. พัฒนาโดย 3 หน่วยงาน คือ nasa, noaa และ usgs nasa: รับผิดชอบด้านการพัฒนาตัวดาวเทียม, อุปกรณ์,. “It’s a fantastic time to be a user of satellite data, if you’re in that moderate resolution domain this is amazing. The Sentinels and Landsat together is going to be really a game changer. It truly is.” LANDSAT 7 satellite is equipped with Enhanced Thematic Mapper Plus (ETM+), the successor of TM. The observation bands are essentially the same seven bands as TM, and the newly added panchromatic band 8, with a high resolution of 15m was added. An instrument malfunction occurred on May 31, 2003, with the result that all Landsat 7 scenes acquired.
Landsat 7 Launched: 1999 Organisation: NASA - USA Landsat 7 ETM+ SLC-off data refers to all Landsat 7 images collected after May 31, 2003, when the Scan Line Corrector (SLC) failed Landsat 7 Views Planet Earth Credit: Landsat 7 Project, NASA. Explanation: Launched last month, NASA's Landsat 7 spacecraft now orbits planet Earth. Looking down from an altitude of 700 km, Landsat 7 can map the planet's surface in visible and infrared bands and resolve features 30 meters across or smaller Insert meta stuff here. Map Credits | Accessibility | FOIA | Privacy | Policies and Notice Landsat 7 The Landsat Program is a series of Earth-observing satellite missions jointly managed by NASA and the U.S. Geological Survey. Since 1972, Landsat satellites have collected information about Earth from space
Landsat 7 was designed to last for five years, and has the capacity to collect and transmit up to 532 images per day. It is in a polar, sun-synchronous orbit, meaning it scans across the entire earth's surface.With an altitude of 705 kilometres +/- 5 kilometres, it takes 232 orbits, or 16 days, to do so Landsat-7 data is received and distributed to the user community by USGS (capturing and processing 250 Landsat scenes per day and delivering at least 100 of the scenes to users each day).NASA/GSFC performed on-orbit mission operations until Oct. 1, 2000; after that responsibility for flight operations and LS-7 management was transferred to the USGS/EDC (flight operations, maintenance, and management of all ground data reception, processing, archiving, product generation, and distribution). The operating philosophy changed to the effect that ETM+ data covering the global continental surfaces are being archived in the USA. The ETM+ archive is continually being updated as data become available. This data policy differs from the past (Landsat-4 and -5), where data was only acquired from the S/C on the basis of customer requests. The new archiving policy will substantially increase the amount of data available to the user community. 33) 34) 35) The program, however, continues functioning today under government management, with Landsat 7 still working in orbit and Landsat 8 is set to launch in February 2013. Seeking more Earth informatio
Landsat Thematic Mapper (TM) Band 1 (0.45 - 0.52u m): provides increased penetration of water bodies and also capable of differentiating soil and rock surfaces from vegetation and for detecting cultural features The Landsat Project is the longest running enterprise for acquisition of moderate resolution imagery of the Earth from space. The Landsat 1 satellite was launced in 1972 and the most recent, Landsat 7 was launced in 1999. The instruments on the Landsat satellites have acquired millions of images I have some Landsat-7 data but i am not sure how to find that latitude/longitude bounding box for the data. The images do not contain any kind of header, however, there was a readme that came with the data which supplies some clues to how the naming convention works but its not enough for me to decipher the location of the image Figure 16: Overview of LS-7 component failures/recoveries over its life until Jan. 2010 (image credit: USGS, Ref. 30)The Landsat 7 ETM+ instrument is designed with the significant exception of the thermal infrared band, where the ground resolution has been improved from 120 to 60 m.