12 / Urban Network Analysis (UNA) + Image Sampler in Grasshopper

Today, we will cover techniques for landscape and urban visualization.

Part 1 – Urban Network Analysis (UNA)

Rhino Demo File Download: CLASS_11_UNA 

Grasshopper File Download: CLASS_11_UNA_2

Reference: http://cityform.mit.edu/projects/una-rhino-toolbox

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Part 2 – Image Sampler in Grasshopper

File Download: CLASS_11_IMAGE_SAMPLER

This definition uses an edited Navermap image of a site to visualize trees.  HillShade data from Arcmap defines the height of the trees (shorter if in shade, taller if in light).

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Preparing a Tree image to be imported into Grasshopper

  • Open Navermap / Google Earth and locate your site.
  • PrintSreen your site and open in Photoshop.
  • As accurately as possible, crop this image to your 200m x 200m site, and edit Image Size to make it square.
  • Using the Magic Wand Tool and adjusting the Tolerance value, with Contiguous unchecked we will select greenery in our site.
  • Copy and paste the green areas into a new layer, and then turn off the original image and save as a new JPG file.
  • Open the JPG file, and adjust saturation levels to 0 to make a black and white image, and invert the image so the trees are white and save.
  • Save the PSD file as well in case of future editing.

*Grasshopper will read WHITE as +ve value and BLACK as –ve value, so we want the trees to be white.

Preparing a Hill Shade image to be imported into Grasshopper

  • Download the HillShadeWM data file by clicking the ArcMap link under View In: http://maps.esrikr.com/arcgis/rest/services/HillshadeWM/ImageServer
  • Open HillShadeWM.lyr file in ARCMap.
  • Locate your site by also turning on a base map.
  • In Layout View, File – Export Map and save as a JPG.
  • In Photoshop, as accurately as possible, crop this image to your 200m x 200m site and edit Image Size to make it square.
  • Edit the Levels to add some contrast and save as a JPG.

*Grasshopper will read WHITE as +ve value and BLACK as –ve value, so areas with SUN will have a higher value.

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