{"id":30,"date":"2015-10-20T23:54:40","date_gmt":"2015-10-21T06:54:40","guid":{"rendered":"https:\/\/blogs.ubc.ca\/rightclickleona\/?p=30"},"modified":"2015-10-21T14:10:09","modified_gmt":"2015-10-21T21:10:09","slug":"understanding-geospatial-data","status":"publish","type":"post","link":"https:\/\/blogs.ubc.ca\/rightclickleona\/2015\/10\/20\/understanding-geospatial-data\/","title":{"rendered":"Understanding (geo)spatial data"},"content":{"rendered":"

The world is an intricate place, but our curious nature always strive to understand our surroundings. \u00a0Before analyzing what goes on around us we must comprehend the information at our disposal.<\/p>\n

The common notion is that planet Earth is a sphere, but as seen in class, it is actually an elliptical geoid, meaning that the poles are actually flat and the surface is not smooth. The idea of \u00a0Earth being round is a simplification to build concepts, and consequently to deepen our knowledge. \u00a0Although simplification aids to perform diverse analysis, projections come at a cost: Distortion. \u00a0It is impossible to reproduce an exact representation of Earth into two dimensions without any distortion. \u00a0Multiple map projections exist with varying distortion, which affects properties such as distance, angles, direction and shape. \u00a0Therefore, it is important to bare in mind the optimal projection when gathering data.<\/p>\n

For lab 2, in one of the layers, nat_parks, the data did not\u00a0match the rest data because of the missing spatial reference.<\/p>\n

The first step is always<\/strong> to take a look at the properties of the datasets you are dealing with:<\/p>\n

    \n
  1. Open ArcCatalog<\/li>\n
  2. Right-click on the layers to find the properties<\/li>\n
  3. Scroll down and you will find the Coordinate Reference System<\/li>\n
  4. Note the projection and inquire to provider if not available, or take a look at the metadata<\/li>\n<\/ol>\n

    The next step is to fix the misaligned layer to match the rest of the datasets:<\/p>\n

      \n
    1. Right-click the layer with missing information,\u00a0nat_parks, and click\u00a0Properties<\/em><\/li>\n
    2. Go to the\u00a0XY Coordinate System <\/em>tab<\/li>\n
    3. Click on\u00a0Geographic Coordinate Systems,\u00a0<\/em>and choose the desired representation. \u00a0In our case, we are interested in North America > NAD 1983.<\/em><\/li>\n<\/ol>\n

      Finally, we must create a new projected layer to execute a specific\u00a0analysis by using\u00a0Data Management Tools><\/em>\u00a0Projections and Transformations > Project. \u00a0<\/em>Fill in the data you want to work with in the\u00a0Input Dataset,\u00a0<\/em>and the computer will use the same coordinate system in use, or you can choose another, and it will project a new data layer in the\u00a0Output.<\/em><\/p>\n

      Landsat Data<\/strong><\/p>\n

      Landsat imagery is an example of data that can be used in GIS. \u00a0Landsat satellites orbit the globe from space and captures moderate resolution imagery of Earth’s surface. \u00a0It is a\u00a0collection of high resolution multispectral digital images by sensing different types of wave length that are even invisible to the human eye. Landsat is used in diverse disciplines to study how landscapes alter following natural phenomena and the consequence of human impacts. \u00a0Here are a few benefits:<\/p>\n

        \n
      1. Longstanding collection of data\u00a0archived since 1972 that allows comparison through time.<\/li>\n
      2. Consistent data captured\u00a0of the Earth’s surface, which lets you monitor\u00a0the appropriate interval of time to study a case.<\/li>\n
      3. High quality information that is accessible to all in the world without charge.<\/li>\n<\/ol>\n

         <\/p>\n

         <\/p>\n

        References<\/em><\/p>\n

        Fort Collins Science Center. Landsat imagery: A unique resource. Retrieved October 19, 2015 from\u00a0https:\/\/www.fort.usgs.gov\/landsat-study<\/a><\/em><\/p>\n

        National Aeronautics and Space Administration (October 10, 2015).\u00a0About: Landsat Then and Now. Retrieved October 19, 2015 from\u00a0http:\/\/landsat.gsfc.nasa.gov\/?page_id=2<\/a><\/em><\/p>\n

        Video:\u00a0G2009 120 Landsat Flyby MASTER youtube hq<\/a>\u00a0Retrieved October 19, 2015 from\u00a0http:\/\/landsat.gsfc.nasa.gov\/?page_id=2<\/a><\/em><\/p>\n

         <\/p>\n","protected":false},"excerpt":{"rendered":"

        The world is an intricate place, but our curious nature always strive to understand our surroundings. \u00a0Before analyzing what goes…<\/p>\n","protected":false},"author":33914,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-30","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/blogs.ubc.ca\/rightclickleona\/wp-json\/wp\/v2\/posts\/30","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.ubc.ca\/rightclickleona\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.ubc.ca\/rightclickleona\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.ubc.ca\/rightclickleona\/wp-json\/wp\/v2\/users\/33914"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.ubc.ca\/rightclickleona\/wp-json\/wp\/v2\/comments?post=30"}],"version-history":[{"count":10,"href":"https:\/\/blogs.ubc.ca\/rightclickleona\/wp-json\/wp\/v2\/posts\/30\/revisions"}],"predecessor-version":[{"id":74,"href":"https:\/\/blogs.ubc.ca\/rightclickleona\/wp-json\/wp\/v2\/posts\/30\/revisions\/74"}],"wp:attachment":[{"href":"https:\/\/blogs.ubc.ca\/rightclickleona\/wp-json\/wp\/v2\/media?parent=30"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.ubc.ca\/rightclickleona\/wp-json\/wp\/v2\/categories?post=30"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.ubc.ca\/rightclickleona\/wp-json\/wp\/v2\/tags?post=30"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}