{"id":208,"date":"2016-08-02T17:54:30","date_gmt":"2016-08-02T16:54:30","guid":{"rendered":"http:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/?page_id=208"},"modified":"2016-08-02T17:55:28","modified_gmt":"2016-08-02T16:55:28","slug":"5-4-spatial-resolution","status":"publish","type":"page","link":"https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/5-sensor-technology\/5-4-spatial-resolution\/","title":{"rendered":"5.4. Spatial Resolution"},"content":{"rendered":"<hr \/>\n<p><strong>Objectives<\/strong><\/p>\n<p>In this learning object students will learn the definition of the spatial resolution of a sensor, and explore the factors which help to determine spatial resolution and its impacts on the information which can be obtained about the target.<\/p>\n<hr \/>\n<p>Spatial resolution refers to the smallest size of an object that can be picked out from its surrounding objects or features. The following images show a succession of increasing resolution from the lowest, in which a wood is just visible on the top of a hill to the highest in which individual fruits are identifiable. A suitable sensor (such as a magnifying glass or microscope) would enable us to view the structure of individual leaves.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/5.12.jpg\" alt=\"5.12\" class=\"alignnone wp-image-209\" height=\"120\" width=\"159\" srcset=\"https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/5.12.jpg 346w, https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/5.12-300x225.jpg 300w\" sizes=\"auto, (max-width: 159px) 100vw, 159px\" \/> <img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/5.13.jpg\" alt=\"5.13\" class=\"alignnone wp-image-210\" height=\"120\" width=\"159\" \/> <img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/5.14.jpg\" alt=\"5.14\" class=\"alignnone wp-image-211\" height=\"120\" width=\"147\" \/>\u00a0<img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/5.15-300x225.jpg\" alt=\"\" class=\"alignnone wp-image-212\" height=\"120\" width=\"160\" srcset=\"https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/5.15-300x225.jpg 300w, https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/5.15.jpg 346w\" sizes=\"auto, (max-width: 160px) 100vw, 160px\" \/><\/p>\n<p>(Image source: David Martin)<\/p>\n<p>The smallest size of an object in a remote sensing system is expressed in units of distance such as km, m, cm, etc. to describe the smallest size of an object that can be picked out. This is mainly determined by the IFOV of the sensor.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/5.16.gif\" alt=\"5.16\" class=\"alignnone size-full wp-image-213\" height=\"17\" width=\"64\" \/><\/p>\n<p>where<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/5.17.gif\" alt=\"5.17\" class=\"alignnone size-full wp-image-214\" height=\"12\" width=\"16\" \/> is the diameter of the ground sampling element (m),<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/5.18.gif\" alt=\"5.18\" class=\"alignnone size-medium wp-image-215\" height=\"12\" width=\"24\" \/>is the flying height of the sensor (m) and<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/5.19.gif\" alt=\"5.19\" class=\"alignnone size-medium wp-image-216\" height=\"17\" width=\"16\" \/>is the IFOV of the sensor instrument (radians)<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/5.20-187x300.jpg\" alt=\"5.20\" class=\"alignnone size-medium wp-image-217\" height=\"300\" width=\"187\" srcset=\"https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/5.20-187x300.jpg 187w, https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/5.20.jpg 203w\" sizes=\"auto, (max-width: 187px) 100vw, 187px\" \/><\/p>\n<p>When spatial resolution is high, we are able to see much detailed information<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/5.21-300x229.jpg\" alt=\"5.21\" class=\"alignnone wp-image-218 size-medium\" height=\"229\" width=\"300\" srcset=\"https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/5.21-300x229.jpg 300w, https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/5.21.jpg 500w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/p>\n<p>This becomes more apparent when searching for recognizable ground features in remotely sensed imagery:<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/5.22.jpg\" alt=\"5.22\" class=\"alignnone wp-image-219 size-full\" height=\"267\" width=\"563\" srcset=\"https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/5.22.jpg 563w, https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/5.22-300x142.jpg 300w\" sizes=\"auto, (max-width: 563px) 100vw, 563px\" \/><\/p>\n<p>In the left hand image above, the ground resolution is 20m, wheras in the right hand image it is 2.5m. It is clear from these images that ground features become more readily identifiable as spatial resolution increases.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/5.23.jpg\" alt=\"5.23\" class=\"alignnone wp-image-220\" height=\"282\" width=\"563\" srcset=\"https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/5.23.jpg 602w, https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/5.23-300x150.jpg 300w\" sizes=\"auto, (max-width: 563px) 100vw, 563px\" \/><\/p>\n<p>The highest spatial resolution available for civilian use until recently has been the GeoEye sensor, with a ground resolution of 50cm.<\/p>\n<p>High spatial resolution sensors cannot cover such a wide area on the ground. High resolution gives much more spatial detail but may in fact provide too much data!<\/p>\n<p>The Earth&#8217;s surface is approximately 500 x 10<sup>6<\/sup> km<sup>2<\/sup>. At 10m resolution this would require 5 x 10<sup>12<\/sup> pixels (&gt; 5 x 10<sup>6<\/sup> Mb per band); at 1km resolution the same area would require 5 x 10<sup>8<\/sup> pixels (&gt;500Mb per band).<\/p>\n<p>However, there are great advantages to high spatial resolution if the user is interested in a specific region for the purposes of urban planning or the estimation of crop yields per field.<\/p>\n<p>There is thus a trade-off between coverage and detail (and data volume).<\/p>\n<hr \/>\n<p><strong>Reflection<\/strong><\/p>\n<p>Which of the following images has the higher spatial resolution?<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/5.24-300x233.jpg\" alt=\"5.24\" class=\"alignnone size-medium wp-image-221\" height=\"233\" width=\"300\" srcset=\"https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/5.24-300x233.jpg 300w, https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/5.24.jpg 509w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/> <img loading=\"lazy\" decoding=\"async\" src=\"http:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/5.25-300x234.jpg\" alt=\"5.25\" class=\"alignnone size-medium wp-image-222\" height=\"234\" width=\"300\" srcset=\"https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/5.25-300x234.jpg 300w, https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-content\/uploads\/sites\/106\/2016\/08\/5.25.jpg 582w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/p>\n<p>\r\n<script>\/\/ <![CDATA[\r\nfunction showFunct() { document.getElementById(\"hideshow\").style.display = \"block\"; } function hideFunct() { document.getElementById(\"hideshow\").style.display = \"none\"; }\r\n\/\/ ]]><\/script>\r\n<\/p>\r\n<p style=\"text-decoration: underline; color: #336699;\" onclick=\"showFunct()\">Show Answer<\/p>\r\n<div id=\"hideshow\" style=\"display: none;\">\r\n<p>The image on the left has the higher spatial resolution - in other words, the pixels represent smaller areas on the ground, hence the image is more detailed and smaller ground features are identifiable.<\/p>\r\n<p style=\"text-decoration: underline; color: #336699; text-align: right;\" button=\"\" onclick=\"hideFunct()\">Hide Answer<\/p>\r\n<\/div>\n<hr \/>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Objectives In this learning object students will learn the definition of the spatial resolution of a sensor, and explore the factors which help to determine spatial resolution and its impacts on the information which can be obtained about the target. Spatial resolution refers to the smallest size of an object that can be picked out [&hellip;]<\/p>\n","protected":false},"author":1726,"featured_media":0,"parent":179,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-208","page","type-page","status-publish","hentry"],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-json\/wp\/v2\/pages\/208","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-json\/wp\/v2\/users\/1726"}],"replies":[{"embeddable":true,"href":"https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-json\/wp\/v2\/comments?post=208"}],"version-history":[{"count":1,"href":"https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-json\/wp\/v2\/pages\/208\/revisions"}],"predecessor-version":[{"id":223,"href":"https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-json\/wp\/v2\/pages\/208\/revisions\/223"}],"up":[{"embeddable":true,"href":"https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-json\/wp\/v2\/pages\/179"}],"wp:attachment":[{"href":"https:\/\/generic.wordpress.soton.ac.uk\/rs4eo\/wp-json\/wp\/v2\/media?parent=208"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}