{"id":1675,"date":"2018-06-27T09:42:24","date_gmt":"2018-06-27T07:42:24","guid":{"rendered":"https:\/\/blogs.fu-berlin.de\/reseda\/?page_id=1675"},"modified":"2019-07-23T13:26:39","modified_gmt":"2019-07-23T11:26:39","slug":"preprocess-optical-data","status":"publish","type":"page","link":"https:\/\/blogs.fu-berlin.de\/reseda\/preprocess-optical-data\/","title":{"rendered":"Preprocess Optical Data"},"content":{"rendered":"<p>Preprocessing optical data in remote sensing (RS) research usually describes the correction of sensor- and platform-specific radiometric and geometric distortions of RS data. Depending on the available data, this can include the following processing steps (not ordered):<\/p>\n<ul>\n<li><strong>radiometric correction<\/strong> due to variations in scene illumination and viewing geometry<\/li>\n<li><strong>geometric correcting \/orthorectification<\/strong> to improve the positional accuracy of image data<\/li>\n<li><strong>atmospheric correction<\/strong> to improve the spectral comparability between two scenes<\/li>\n<li><strong>convertion <\/strong> of data into various units (e.g., TOA radiation to reflectance) or between different data types (e.g., .img to .tiff)<\/li>\n<li><strong>compression or subsetting <\/strong> data to save disc space<\/li>\n<\/ul>\n<p>Fortunately, both <strong>Landsat 8<\/strong> and <strong>Sentinel 2<\/strong> Level-1 products are already radiometrically and geometrically corrected. If you use Level-2 scenes, the atmosphere correction is already done on both products by the data provider, which is a prerequisite especially for a time series analysis. So there is no need for you to do either of this corrections any more!<br \/>\nWe want to focus on converting the just-downloaded products into GeoTIFF files. A GeoTIFF file is a standard used in many GIS and RS software solutions and allows georeferencing information to be embedded within the TIFF-file itself. Such information includes the map projection, the coordinate system, the ellipsoid, the geodetic datum, the geospatial extent, and many more.<\/p>\n<p>&nbsp;<\/p>\n<hr style=\"height: 4px;background-color: #6b9e1f\" \/>\n<div style=\"font-family: 'Noto Sans', sans-serif;line-height: 1.2;text-align: right\"><span style=\"font-size: 12px;color: #bfbfbf\"><strong><em>NEXT<\/em><\/strong><\/span><br \/>\n<a style=\"text-decoration: none\" href=\"https:\/\/blogs.fu-berlin.de\/reseda\/landsat-8-preprocessing\/\"><span style=\"font-size: 30px;color: #6b9e1f\"><strong><em>LANDSAT 8 PREPROCESSING<\/em><\/strong><\/span><\/a><\/div>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Preprocessing optical data in remote sensing (RS) research usually describes the correction of sensor- and platform-specific radiometric and geometric distortions of RS data. Depending on the available data, this can include the following processing steps (not ordered): radiometric correction due to variations in scene illumination and viewing geometry geometric correcting \/orthorectification to improve the positional &hellip; <a href=\"https:\/\/blogs.fu-berlin.de\/reseda\/preprocess-optical-data\/\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"> &#8220;Preprocess Optical Data&#8221;<\/span><\/a><\/p>\n","protected":false},"author":3237,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-1675","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/blogs.fu-berlin.de\/reseda\/wp-json\/wp\/v2\/pages\/1675","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.fu-berlin.de\/reseda\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/blogs.fu-berlin.de\/reseda\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.fu-berlin.de\/reseda\/wp-json\/wp\/v2\/users\/3237"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.fu-berlin.de\/reseda\/wp-json\/wp\/v2\/comments?post=1675"}],"version-history":[{"count":14,"href":"https:\/\/blogs.fu-berlin.de\/reseda\/wp-json\/wp\/v2\/pages\/1675\/revisions"}],"predecessor-version":[{"id":2947,"href":"https:\/\/blogs.fu-berlin.de\/reseda\/wp-json\/wp\/v2\/pages\/1675\/revisions\/2947"}],"wp:attachment":[{"href":"https:\/\/blogs.fu-berlin.de\/reseda\/wp-json\/wp\/v2\/media?parent=1675"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}