{"id":113,"date":"2017-01-30T18:30:49","date_gmt":"2017-01-31T01:30:49","guid":{"rendered":"https:\/\/blogs.ubc.ca\/tessaowens\/?p=113"},"modified":"2017-04-16T12:17:49","modified_gmt":"2017-04-16T19:17:49","slug":"lab-2-spatial-data","status":"publish","type":"post","link":"https:\/\/blogs.ubc.ca\/tessaowens\/2017\/01\/30\/lab-2-spatial-data\/","title":{"rendered":"Misaligned and Improperly Referenced Spatial Data"},"content":{"rendered":"

Read on to learn about projected coordinate systems<\/strong>, distortions, how to take steps to avoid\u00a0mismatching<\/strong> data layers with coordinate systems, and why using Landsat<\/strong> data can be advantageous for your geographic analysis!<\/h3>\n
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Projected coordinate systems are used in GIS to display information in a 2D, workable form. Data projected\u00a0in this form creates the display layers in maps. However, there are many different\u00a0types of projected coordinate systems that use different algorithms to translate 3D\u00a0data into 2D map images. It’s impossible to project 3D data in a 100% accurate way onto a 2D map.<\/p>\n

\"\"<\/p>\n

To compromise, different algorithms prioritize different elements of display: some algorithms may\u00a0display distance more accurately, whereas other algorithms\u00a0may result in a more accurate display of landform size.<\/p>\n

Thus, the difference in these algorithms can cause map projections to display disparate\u00a0distances between two points; for instance, if the\u00a0distance between Halifax and Vancouver was measured while using GIS software, the\u00a0measurement may differ (in the range of a few kilometers) depending on which projected coordinate system is utilized.<\/p>\n

In order to minimize this distortion, both the projected coordinate system and the geographic coordinate system should match. The following steps should be followed in order to ensure smooth operations:<\/p>\n

1. \u00a0Preview the data with ArcCatalog, check which layers include information regarding their coordinate systems, or not.<\/p>\n

2. Find out what the official projections are for the area of study; these differ from region to region.<\/p>\n

3. Convert all layers into the common projection that has been identified.<\/p>\n

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Landsat images\u00a0contain the longest visual record of Earth’s surface. The data provided through Landsat technology is coarse enough to offer global coverage, but is detailed enough to illustrate important developments on Earth’s surface. These may include\u00a0images that range from illustrating the\u00a0change and growth of human infrastructure on Earth\u00a0to the retreat of glaciers in water storage areas of the world. Because of its prolific history, Landsat data can be used to supplement study on global topics such as climate change, desertification, and urbanization.<\/p>\n

Melting ice in Antarctica. Photo: Tessa Owens, 2014<\/figcaption><\/figure>\n
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Images provided courtesy of Tessa Owens (SOI Antarctic Expedition, 2014) and pixabay.com, a\u00a0website hosting\u00a0images and videos free of\u00a0copyrights.\u00a0<\/em><\/p>\n

Accomplishment Statement<\/strong><\/h1>\n

Through the completion of this lab, I have learned about the differences between geographic coordinate systems and projected coordinate systems in GIS software. I have learned how to overcome barriers in data sourced from different coordinate systems and include these data in my GIS analysis. I have also continued to gain\u00a0more experience in navigating GIS software.<\/p>\n","protected":false},"excerpt":{"rendered":"

Read on to learn about projected coordinate systems, distortions, how to take steps to avoid\u00a0mismatching data layers with coordinate systems, and why using Landsat data can be advantageous for your geographic analysis! Projected coordinate systems are used in GIS to display information in a 2D, workable form. Data projected\u00a0in this form creates the display layers … <\/p>\n

Continue reading “Misaligned and Improperly Referenced Spatial Data”<\/span><\/a><\/p>\n","protected":false},"author":48742,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[747,71,1699025],"tags":[1328401],"class_list":["post-113","post","type-post","status-publish","format-standard","hentry","category-academics","category-courses","category-major-discipline","tag-geob-270"],"_links":{"self":[{"href":"https:\/\/blogs.ubc.ca\/tessaowens\/wp-json\/wp\/v2\/posts\/113","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.ubc.ca\/tessaowens\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.ubc.ca\/tessaowens\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.ubc.ca\/tessaowens\/wp-json\/wp\/v2\/users\/48742"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.ubc.ca\/tessaowens\/wp-json\/wp\/v2\/comments?post=113"}],"version-history":[{"count":7,"href":"https:\/\/blogs.ubc.ca\/tessaowens\/wp-json\/wp\/v2\/posts\/113\/revisions"}],"predecessor-version":[{"id":180,"href":"https:\/\/blogs.ubc.ca\/tessaowens\/wp-json\/wp\/v2\/posts\/113\/revisions\/180"}],"wp:attachment":[{"href":"https:\/\/blogs.ubc.ca\/tessaowens\/wp-json\/wp\/v2\/media?parent=113"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.ubc.ca\/tessaowens\/wp-json\/wp\/v2\/categories?post=113"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.ubc.ca\/tessaowens\/wp-json\/wp\/v2\/tags?post=113"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}