{"id":382,"date":"2015-11-24T15:14:39","date_gmt":"2015-11-24T22:14:39","guid":{"rendered":"https:\/\/blogs.ubc.ca\/advancedgis\/?page_id=382"},"modified":"2016-11-08T10:06:07","modified_gmt":"2016-11-08T17:06:07","slug":"spatial-interpolation-explanatory-examples","status":"publish","type":"page","link":"https:\/\/blogs.ubc.ca\/advancedgis\/schedule\/slides\/spatial-analysis-2\/spatial-interpolation-explanatory-examples\/","title":{"rendered":"Spatial Interpolation Explanatory Examples"},"content":{"rendered":"<p><div id=\"random-accordion-id-37\" class=\"accordion-shortcode explanation \">\n<h3 ><a href=\"#interpolation-problem-0\" >Interpolation Problem<\/a><\/h3><div id=\"interpolation-problem-0\" class=\"accordian-shortcode-content \" ><p>A simple explanation of the interpolation problem (ignores commonly used functions such as inverse distance squared, however):<br \/>\n<img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-219\" src=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/Interpolation-1D.gif\" alt=\"Interpolation 1D\" width=\"439\" height=\"593\" \/><\/p>\n<p style=\"text-align: center;\">(Source: <a href=\"http:\/\/www4.ncsu.edu\/~hmitaso\/gmslab\/viz\/interp1d.html\" target=\"_blank\">http:\/\/www4.ncsu.edu\/~hmitaso\/gmslab\/viz\/interp1d.html<\/a>)<\/p>\n<p>\n<\/div>\n<h3 ><a href=\"#five-different-surfaces-1\" >Five Different Surfaces<\/a><\/h3><div id=\"five-different-surfaces-1\" class=\"accordian-shortcode-content \" ><\/p>\n<p>Surfaces created from the same data.<\/p>\n\n\t\t<style>\n\t\t\t#gallery-1 {\n\t\t\t\tmargin: auto;\n\t\t\t}\n\t\t\t#gallery-1 .gallery-item {\n\t\t\t\tfloat: left;\n\t\t\t\tmargin-top: 10px;\n\t\t\t\ttext-align: center;\n\t\t\t\twidth: 33%;\n\t\t\t}\n\t\t\t#gallery-1 img {\n\t\t\t\tborder: 2px solid #cfcfcf;\n\t\t\t}\n\t\t\t#gallery-1 .gallery-caption {\n\t\t\t\tmargin-left: 0;\n\t\t\t}\n\t\t\t\/* see gallery_shortcode() in wp-includes\/media.php *\/\n\t\t<\/style>\n\t\t<div id='gallery-1' class='gallery galleryid-382 gallery-columns-3 gallery-size-thumbnail'><dl class='gallery-item'>\n\t\t\t<dt class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/blogs.ubc.ca\/advancedgis\/schedule\/slides\/spatial-analysis-2\/spatial-interpolation-explanatory-examples\/tin\/'><img loading=\"lazy\" decoding=\"async\" width=\"150\" height=\"150\" src=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/TIN-150x150.gif\" class=\"attachment-thumbnail size-thumbnail\" alt=\"\" aria-describedby=\"gallery-1-504\" \/><\/a>\n\t\t\t<\/dt>\n\t\t\t\t<dd class='wp-caption-text gallery-caption' id='gallery-1-504'>\n\t\t\t\tTIN\n\t\t\t\t<\/dd><\/dl><dl class='gallery-item'>\n\t\t\t<dt class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/blogs.ubc.ca\/advancedgis\/schedule\/slides\/spatial-analysis-2\/spatial-interpolation-explanatory-examples\/topogrid\/'><img loading=\"lazy\" decoding=\"async\" width=\"150\" height=\"150\" src=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/Topogrid-150x150.gif\" class=\"attachment-thumbnail size-thumbnail\" alt=\"\" aria-describedby=\"gallery-1-505\" \/><\/a>\n\t\t\t<\/dt>\n\t\t\t\t<dd class='wp-caption-text gallery-caption' id='gallery-1-505'>\n\t\t\t\tTopogrid\n\t\t\t\t<\/dd><\/dl><dl class='gallery-item'>\n\t\t\t<dt class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/blogs.ubc.ca\/advancedgis\/schedule\/slides\/spatial-analysis-2\/spatial-interpolation-explanatory-examples\/voronoi\/'><img loading=\"lazy\" decoding=\"async\" width=\"150\" height=\"150\" src=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/voronoi-150x150.gif\" class=\"attachment-thumbnail size-thumbnail\" alt=\"\" aria-describedby=\"gallery-1-506\" \/><\/a>\n\t\t\t<\/dt>\n\t\t\t\t<dd class='wp-caption-text gallery-caption' id='gallery-1-506'>\n\t\t\t\tVoronoi\n\t\t\t\t<\/dd><\/dl><br style=\"clear: both\" \/><dl class='gallery-item'>\n\t\t\t<dt class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/blogs.ubc.ca\/advancedgis\/schedule\/slides\/spatial-analysis-2\/spatial-interpolation-explanatory-examples\/kriging\/'><img loading=\"lazy\" decoding=\"async\" width=\"150\" height=\"150\" src=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/Kriging-150x150.gif\" class=\"attachment-thumbnail size-thumbnail\" alt=\"\" aria-describedby=\"gallery-1-508\" \/><\/a>\n\t\t\t<\/dt>\n\t\t\t\t<dd class='wp-caption-text gallery-caption' id='gallery-1-508'>\n\t\t\t\tKriging\n\t\t\t\t<\/dd><\/dl><dl class='gallery-item'>\n\t\t\t<dt class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/blogs.ubc.ca\/advancedgis\/schedule\/slides\/spatial-analysis-2\/spatial-interpolation-explanatory-examples\/idw\/'><img loading=\"lazy\" decoding=\"async\" width=\"150\" height=\"150\" src=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/IDW-150x150.gif\" class=\"attachment-thumbnail size-thumbnail\" alt=\"\" aria-describedby=\"gallery-1-507\" \/><\/a>\n\t\t\t<\/dt>\n\t\t\t\t<dd class='wp-caption-text gallery-caption' id='gallery-1-507'>\n\t\t\t\tIDW\n\t\t\t\t<\/dd><\/dl>\n\t\t\t<br style='clear: both' \/>\n\t\t<\/div>\n\n<p style=\"text-align: center;\">Source: Lubos Mitas and Helena Mitasova (<a href=\"http:\/\/www4.ncsu.edu\/~hmitaso\/gmslab\/viz\/sinter.html\" target=\"_blank\">http:\/\/www4.ncsu.edu\/~hmitaso\/gmslab\/viz\/sinter.html<\/a>)<\/p>\n<p>\n<\/div>\n<h3 ><a href=\"#inverse-distance-weights-2\" >Inverse Distance Weights<\/a><\/h3><div id=\"inverse-distance-weights-2\" class=\"accordian-shortcode-content \" ><p>The exponent associated with inverse distance weights determines how quickly the influence of neighbouring points drops off. With inverse distance, when trying to estimate an elevation (e.g.) at an unknown location, the weight (or significance) the interpolating routine gives to the elevation value at each known (sampled) location decays rapidly as the distance between the known and unknown points increases. How rapidly this occurs can be adjusted to best fit your real world situation by adjusting the value of the exponent. This graph illustrates the influence on inverse distance weighting for exponents 1 - 6. Note that you can use an exponent of less than 1, although that would give points further away a greater influence than nearer points! Typically weights of 1 or 2 are used.<br \/>\n<img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-220\" src=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/Inverse-Distance-Weights.gif\" alt=\"Inverse Distance Weights\" width=\"715\" height=\"503\" \/><\/p>\n<\/div>\n<h3 ><a href=\"#dem-data-comparison-3\" >DEM Data Comparison<\/a><\/h3><div id=\"dem-data-comparison-3\" class=\"accordian-shortcode-content \" ><\/p>\n<p>Below\u00a0is a comparison of how different sources of DEM data--at different resolutions but for the same area--differ significantly in their representations (posted with permission of Dave Patton, original source:\u00a0<a href=\"http:\/\/members.shaw.ca\/davepatton\/demcompare.html\" target=\"_blank\">http:\/\/members.shaw.ca\/davepatton\/demcompare.html<\/a>)<\/p>\n\n\t\t<style>\n\t\t\t#gallery-2 {\n\t\t\t\tmargin: auto;\n\t\t\t}\n\t\t\t#gallery-2 .gallery-item {\n\t\t\t\tfloat: left;\n\t\t\t\tmargin-top: 10px;\n\t\t\t\ttext-align: center;\n\t\t\t\twidth: 50%;\n\t\t\t}\n\t\t\t#gallery-2 img {\n\t\t\t\tborder: 2px solid #cfcfcf;\n\t\t\t}\n\t\t\t#gallery-2 .gallery-caption {\n\t\t\t\tmargin-left: 0;\n\t\t\t}\n\t\t\t\/* see gallery_shortcode() in wp-includes\/media.php *\/\n\t\t<\/style>\n\t\t<div id='gallery-2' class='gallery galleryid-382 gallery-columns-2 gallery-size-medium'><dl class='gallery-item'>\n\t\t\t<dt class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/blogs.ubc.ca\/advancedgis\/schedule\/slides\/spatial-analysis-2\/spatial-interpolation-explanatory-examples\/srtm30frame\/'><img loading=\"lazy\" decoding=\"async\" width=\"300\" height=\"191\" src=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/srtm30frame-300x191.png\" class=\"attachment-medium size-medium\" alt=\"\" aria-describedby=\"gallery-2-528\" srcset=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/srtm30frame-300x191.png 300w, https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/srtm30frame.png 800w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a>\n\t\t\t<\/dt>\n\t\t\t\t<dd class='wp-caption-text gallery-caption' id='gallery-2-528'>\n\t\t\t\tWireframe image using the SRTM 30 arc-second data, which is a &#8220;near-global digital elevation model (DEM) comprising a combination of data from the Shuttle Radar Topography Mission, flown in February, 2000 and the the U.S. Geological Survey&#8217;s GTOPO30 data set&#8221;.\n\t\t\t\t<\/dd><\/dl><dl class='gallery-item'>\n\t\t\t<dt class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/blogs.ubc.ca\/advancedgis\/schedule\/slides\/spatial-analysis-2\/spatial-interpolation-explanatory-examples\/srtm30map\/'><img loading=\"lazy\" decoding=\"async\" width=\"300\" height=\"191\" src=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/srtm30map-300x191.png\" class=\"attachment-medium size-medium\" alt=\"\" aria-describedby=\"gallery-2-529\" srcset=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/srtm30map-300x191.png 300w, https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/srtm30map.png 800w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a>\n\t\t\t<\/dt>\n\t\t\t\t<dd class='wp-caption-text gallery-caption' id='gallery-2-529'>\n\t\t\t\tMap image using the SRTM 30 arc-second data, which is a &#8220;near-global digital elevation model (DEM) comprising a combination of data from the Shuttle Radar Topography Mission, flown in February, 2000 and the the U.S. Geological Survey&#8217;s GTOPO30 data set&#8221;.\n\t\t\t\t<\/dd><\/dl><br style=\"clear: both\" \/><dl class='gallery-item'>\n\t\t\t<dt class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/blogs.ubc.ca\/advancedgis\/schedule\/slides\/spatial-analysis-2\/spatial-interpolation-explanatory-examples\/srtm3map\/'><img loading=\"lazy\" decoding=\"async\" width=\"300\" height=\"191\" src=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/srtm3map-300x191.png\" class=\"attachment-medium size-medium\" alt=\"\" aria-describedby=\"gallery-2-527\" srcset=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/srtm3map-300x191.png 300w, https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/srtm3map.png 800w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a>\n\t\t\t<\/dt>\n\t\t\t\t<dd class='wp-caption-text gallery-caption' id='gallery-2-527'>\n\t\t\t\tMap image using the 3 arc-second SRTM (Shuttle Radar Topography Mission) North American data.\n\t\t\t\t<\/dd><\/dl><dl class='gallery-item'>\n\t\t\t<dt class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/blogs.ubc.ca\/advancedgis\/schedule\/slides\/spatial-analysis-2\/spatial-interpolation-explanatory-examples\/srtm3frame\/'><img loading=\"lazy\" decoding=\"async\" width=\"300\" height=\"191\" src=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/srtm3frame-300x191.png\" class=\"attachment-medium size-medium\" alt=\"\" aria-describedby=\"gallery-2-526\" srcset=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/srtm3frame-300x191.png 300w, https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/srtm3frame.png 800w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a>\n\t\t\t<\/dt>\n\t\t\t\t<dd class='wp-caption-text gallery-caption' id='gallery-2-526'>\n\t\t\t\tWireframe image using the 3 arc-second SRTM (Shuttle Radar Topography Mission) North American data.\n\t\t\t\t<\/dd><\/dl><br style=\"clear: both\" \/><dl class='gallery-item'>\n\t\t\t<dt class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/blogs.ubc.ca\/advancedgis\/schedule\/slides\/spatial-analysis-2\/spatial-interpolation-explanatory-examples\/gtopo30map\/'><img loading=\"lazy\" decoding=\"async\" width=\"300\" height=\"191\" src=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/gtopo30map-300x191.png\" class=\"attachment-medium size-medium\" alt=\"\" aria-describedby=\"gallery-2-525\" srcset=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/gtopo30map-300x191.png 300w, https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/gtopo30map.png 800w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a>\n\t\t\t<\/dt>\n\t\t\t\t<dd class='wp-caption-text gallery-caption' id='gallery-2-525'>\n\t\t\t\tMap image using the 30 arc-second GTOPO30 data.\n\t\t\t\t<\/dd><\/dl><dl class='gallery-item'>\n\t\t\t<dt class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/blogs.ubc.ca\/advancedgis\/schedule\/slides\/spatial-analysis-2\/spatial-interpolation-explanatory-examples\/gtopo30frame\/'><img loading=\"lazy\" decoding=\"async\" width=\"300\" height=\"191\" src=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/gtopo30frame-300x191.png\" class=\"attachment-medium size-medium\" alt=\"\" aria-describedby=\"gallery-2-524\" srcset=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/gtopo30frame-300x191.png 300w, https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/gtopo30frame.png 800w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a>\n\t\t\t<\/dt>\n\t\t\t\t<dd class='wp-caption-text gallery-caption' id='gallery-2-524'>\n\t\t\t\tWireframe image using the 30 arc-second GTOPO30 data.\n\t\t\t\t<\/dd><\/dl><br style=\"clear: both\" \/><dl class='gallery-item'>\n\t\t\t<dt class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/blogs.ubc.ca\/advancedgis\/schedule\/slides\/spatial-analysis-2\/spatial-interpolation-explanatory-examples\/globeframe\/'><img loading=\"lazy\" decoding=\"async\" width=\"300\" height=\"191\" src=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/globeframe-300x191.png\" class=\"attachment-medium size-medium\" alt=\"\" aria-describedby=\"gallery-2-522\" srcset=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/globeframe-300x191.png 300w, https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/globeframe.png 800w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a>\n\t\t\t<\/dt>\n\t\t\t\t<dd class='wp-caption-text gallery-caption' id='gallery-2-522'>\n\t\t\t\tWireframe image using the GLOBE 30 arc-second data.\n\t\t\t\t<\/dd><\/dl><dl class='gallery-item'>\n\t\t\t<dt class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/blogs.ubc.ca\/advancedgis\/schedule\/slides\/spatial-analysis-2\/spatial-interpolation-explanatory-examples\/globemap\/'><img loading=\"lazy\" decoding=\"async\" width=\"300\" height=\"191\" src=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/globemap-300x191.png\" class=\"attachment-medium size-medium\" alt=\"\" aria-describedby=\"gallery-2-523\" srcset=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/globemap-300x191.png 300w, https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/globemap.png 800w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a>\n\t\t\t<\/dt>\n\t\t\t\t<dd class='wp-caption-text gallery-caption' id='gallery-2-523'>\n\t\t\t\tMap image using the GLOBE 30 arc-second data.\n\t\t\t\t<\/dd><\/dl><br style=\"clear: both\" \/><dl class='gallery-item'>\n\t\t\t<dt class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/blogs.ubc.ca\/advancedgis\/schedule\/slides\/spatial-analysis-2\/spatial-interpolation-explanatory-examples\/dted0map\/'><img loading=\"lazy\" decoding=\"async\" width=\"300\" height=\"191\" src=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/dted0map-300x191.png\" class=\"attachment-medium size-medium\" alt=\"\" aria-describedby=\"gallery-2-521\" srcset=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/dted0map-300x191.png 300w, https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/dted0map.png 800w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a>\n\t\t\t<\/dt>\n\t\t\t\t<dd class='wp-caption-text gallery-caption' id='gallery-2-521'>\n\t\t\t\tMap image using the NIMA (now called NGA) 30 arc-second DTED Level 0 data.\n\t\t\t\t<\/dd><\/dl><dl class='gallery-item'>\n\t\t\t<dt class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/blogs.ubc.ca\/advancedgis\/schedule\/slides\/spatial-analysis-2\/spatial-interpolation-explanatory-examples\/cded1250map\/'><img loading=\"lazy\" decoding=\"async\" width=\"300\" height=\"191\" src=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/cded1250map-300x191.png\" class=\"attachment-medium size-medium\" alt=\"\" aria-describedby=\"gallery-2-519\" srcset=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/cded1250map-300x191.png 300w, https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/cded1250map.png 800w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a>\n\t\t\t<\/dt>\n\t\t\t\t<dd class='wp-caption-text gallery-caption' id='gallery-2-519'>\n\t\t\t\tMap image using the 3 arc-second GeoBase Canadian Digital Elevation Data Level 1 DEM at 1:250,000 scale.\n\t\t\t\t<\/dd><\/dl><br style=\"clear: both\" \/><dl class='gallery-item'>\n\t\t\t<dt class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/blogs.ubc.ca\/advancedgis\/schedule\/slides\/spatial-analysis-2\/spatial-interpolation-explanatory-examples\/dted0frame\/'><img loading=\"lazy\" decoding=\"async\" width=\"300\" height=\"191\" src=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/dted0frame-300x191.png\" class=\"attachment-medium size-medium\" alt=\"\" aria-describedby=\"gallery-2-520\" srcset=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/dted0frame-300x191.png 300w, https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/dted0frame.png 800w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a>\n\t\t\t<\/dt>\n\t\t\t\t<dd class='wp-caption-text gallery-caption' id='gallery-2-520'>\n\t\t\t\tWireframe image using the NIMA (now called NGA) 30 arc-second DTED Level 0 data.GLOBE 30 arc-second\n\t\t\t\t<\/dd><\/dl><dl class='gallery-item'>\n\t\t\t<dt class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/blogs.ubc.ca\/advancedgis\/schedule\/slides\/spatial-analysis-2\/spatial-interpolation-explanatory-examples\/cded1250frame\/'><img loading=\"lazy\" decoding=\"async\" width=\"300\" height=\"191\" src=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/cded1250frame-300x191.png\" class=\"attachment-medium size-medium\" alt=\"\" aria-describedby=\"gallery-2-518\" srcset=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/cded1250frame-300x191.png 300w, https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/cded1250frame.png 800w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a>\n\t\t\t<\/dt>\n\t\t\t\t<dd class='wp-caption-text gallery-caption' id='gallery-2-518'>\n\t\t\t\tWireframe image using the 3 arc-second GeoBase Canadian Digital Elevation Data Level 1 DEM at 1:250,000 scale.\n\t\t\t\t<\/dd><\/dl><br style=\"clear: both\" \/><dl class='gallery-item'>\n\t\t\t<dt class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/blogs.ubc.ca\/advancedgis\/schedule\/slides\/spatial-analysis-2\/spatial-interpolation-explanatory-examples\/cded150klandsat7\/'><img loading=\"lazy\" decoding=\"async\" width=\"300\" height=\"182\" src=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/cded150Klandsat7-300x182.png\" class=\"attachment-medium size-medium\" alt=\"\" aria-describedby=\"gallery-2-516\" srcset=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/cded150Klandsat7-300x182.png 300w, https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/cded150Klandsat7.png 800w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a>\n\t\t\t<\/dt>\n\t\t\t\t<dd class='wp-caption-text gallery-caption' id='gallery-2-516'>\n\t\t\t\tPart of a satellite image from the GeoGratis Landsat-7 Orthorectified Imagery over Canada, using the 0.75 arc-second GeoBase Canadian Digital Elevation Data Level 1 DEM at 1:50,000 scale.\n\t\t\t\t<\/dd><\/dl><dl class='gallery-item'>\n\t\t\t<dt class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/blogs.ubc.ca\/advancedgis\/schedule\/slides\/spatial-analysis-2\/spatial-interpolation-explanatory-examples\/cded150kmap\/'><img loading=\"lazy\" decoding=\"async\" width=\"300\" height=\"191\" src=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/cded150Kmap-300x191.png\" class=\"attachment-medium size-medium\" alt=\"\" aria-describedby=\"gallery-2-517\" srcset=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/cded150Kmap-300x191.png 300w, https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/cded150Kmap.png 800w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a>\n\t\t\t<\/dt>\n\t\t\t\t<dd class='wp-caption-text gallery-caption' id='gallery-2-517'>\n\t\t\t\tMap image using the 0.75 arc-second GeoBase Canadian Digital Elevation Data Level 1 DEM at 1:50,000 scale.\n\t\t\t\t<\/dd><\/dl><br style=\"clear: both\" \/><dl class='gallery-item'>\n\t\t\t<dt class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/blogs.ubc.ca\/advancedgis\/schedule\/slides\/spatial-analysis-2\/spatial-interpolation-explanatory-examples\/cded150kframe\/'><img loading=\"lazy\" decoding=\"async\" width=\"300\" height=\"191\" src=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/cded150Kframe-300x191.png\" class=\"attachment-medium size-medium\" alt=\"\" aria-describedby=\"gallery-2-515\" srcset=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/cded150Kframe-300x191.png 300w, https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/cded150Kframe.png 800w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a>\n\t\t\t<\/dt>\n\t\t\t\t<dd class='wp-caption-text gallery-caption' id='gallery-2-515'>\n\t\t\t\tWireframe image using the 0.75 arc-second GeoBase Canadian Digital Elevation Data Level 1 DEM at 1:50,000 scale.\n\t\t\t\t<\/dd><\/dl>\n\t\t\t<br style='clear: both' \/>\n\t\t<\/div>\n\n<p>\n<\/div>\n<h3 ><a href=\"#areal-interpolation-4\" >Areal Interpolation<\/a><\/h3><div id=\"areal-interpolation-4\" class=\"accordian-shortcode-content \" ><p><a href=\"http:\/\/www.geog.ucsb.edu\/~tobler\/presentations\/Pycnophylactic-reallocation.pdf\" target=\"_blank\">Download this presentation by Dr. Waldo Tobler<\/a>--the person who developed <a href=\"http:\/\/www.geog.ucsb.edu\/~kclarke\/Geography232\/Pycno.pdf\" target=\"_blank\">pycnophylactic interpolation<\/a> or reallocation.<\/p>\n<\/div>\n<h3 ><a href=\"#pycnophylactic-interpolation-5\" >Pycnophylactic Interpolation<\/a><\/h3><div id=\"pycnophylactic-interpolation-5\" class=\"accordian-shortcode-content \" ><p>A simple graphic example of pycnophylactic interpolation (note how the transitions between the areal units becomes smoother, and also how the <strong>volume<\/strong> within each areal unit remains constant [i.e., if some of the blocks within an area get taller, others will get shorter to compensate]).<img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-113 aligncenter\" src=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/Pycno.png\" alt=\"Pycno\" width=\"679\" height=\"410\" srcset=\"https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/Pycno.png 679w, https:\/\/blogs.ubc.ca\/advancedgis\/files\/2015\/11\/Pycno-300x181.png 300w\" sizes=\"auto, (max-width: 679px) 100vw, 679px\" \/><\/p>\n<\/div>\n<\/div><!-- #random-accordion-id-37end of accordion shortcode --><br \/>\n<div id=\"random-accordion-id-382\" class=\"accordion-shortcode  \"><\/div><!-- #random-accordion-id-382end of accordion shortcode --><\/p>\n","protected":false},"excerpt":{"rendered":"","protected":false},"author":18620,"featured_media":0,"parent":109,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-382","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/blogs.ubc.ca\/advancedgis\/wp-json\/wp\/v2\/pages\/382","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.ubc.ca\/advancedgis\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/blogs.ubc.ca\/advancedgis\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.ubc.ca\/advancedgis\/wp-json\/wp\/v2\/users\/18620"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.ubc.ca\/advancedgis\/wp-json\/wp\/v2\/comments?post=382"}],"version-history":[{"count":18,"href":"https:\/\/blogs.ubc.ca\/advancedgis\/wp-json\/wp\/v2\/pages\/382\/revisions"}],"predecessor-version":[{"id":1927,"href":"https:\/\/blogs.ubc.ca\/advancedgis\/wp-json\/wp\/v2\/pages\/382\/revisions\/1927"}],"up":[{"embeddable":true,"href":"https:\/\/blogs.ubc.ca\/advancedgis\/wp-json\/wp\/v2\/pages\/109"}],"wp:attachment":[{"href":"https:\/\/blogs.ubc.ca\/advancedgis\/wp-json\/wp\/v2\/media?parent=382"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}