Wednesday, May 28, 2008

Rising Block HowTo

Back before Xmas I wrote about Declan de Paor and his work on rising blocks or 'BumpOuts' as he calls them. You put an image of a geological cross section or other sub surface data on a block, using the time slider to drag a the block out of Google Earth. This gives users a sense of location, scale and the idea that the cross section you are using is actually a cross section (often students miss even that point).


video
Rising Block in action. Sorry about the low quality video.

I've worked out how to do them and here is a howto:

  1. Using Google Earth select the location where you want to put your block. Fly vertically over the area and using 'Prnt Scrn' or equivalent capture an image of the area.
  2. Trim the image you collected in (1) to the exact rectangle on the ground you want using your favourite image processing tool. I use fireworks but GIMP is free.
  3. Also using your image software process the image to go on the side of the block if needs be, save both images as types that sketchup can read (e.g. .jpg or .png)
  4. Using Sketchup draw a simple block not bigger than a house. Sketchup has lots of good tutorials so I won't go into details.
  5. Using File > Import, import both images into sketchup and drag them onto your block and position. This is pretty intuiative. The screen shot goes on top and the section image goes on whichever side you wish. Using the push/pull tool resize your block so your images fit exactly on the faces you have put them.
  6. Save your block as a .skp file to be sure.
  7. Link your block with its location in Google Earth and import
  8. Now find the model in the places folder (its inside the folders and has a 3D box icon)
  9. Right click and select properties, when the green square appears drag it and resize it until your block is the correct size and in the correct position. When you're happy click OK.
  10. Right click the model icon in the places column and select 'save as', save it somewhere sensible as a .kmz file.
  11. Right click the model icon again and select 'copy'.
  12. Open my 'blocker' XL work book, clear the 'Scratch Sheet' (the data that is there shows you what you should get). Select cell A1, right click > paste. You should see a load of text appear. Don't worry that you don't understand the code, you don't need to.
  13. Moving to the 'Process' sheet you have to replace the white cells here with data from the scratch sheet. You need to find the tags within the scratch sheet for <longitude>, <latitude>, <x>, <y>, <z> and <href> and copy them to the relevant cells on the process sheet. To do this Ctrl F for find is your friend. I've shown you exactly how the cells in column C should look in column E of the Process sheet.
  14. Enter the 'Start Depth of Block', in C4, this is the depth the first block will be buried to and should represent the height of your block. Note its a negative value!
  15. Once you have copied in values for all the white squares you're ready to go. Select cell A1 on the 'Out' sheet and right click > copy.
  16. Right click on the 'My Places' icon at the top of the Places column, select paste.
  17. Click on the 'Time Block' icon that appears and your blocks should animate by using the timeline.
Phew! Its a pretty long process so not for the faint of heart. However, as with all processes like this it gets quicker once you've been through it once. The result is worth the effort especially when you combine blocks - we are looking at animating ice core data and lake sediment data for our geography students to use in practicals.

I think the XL file should work but be wary, its not user tested yet.

I'll put an example KMZ file up tomorrow, I really need to slim it down in size before you all start grabbing it.

Later: I've just edited the text as point 13 wasn't appearing properly

Later Still: Not the one in the video but one of lake temperature with depth

2 comments:

mswilke@depauw.edu said...

Very cool to have the how to...however, when I try to run your file on my Mac with version 4.3, it doesn't work. Any ideas?

Rich Treves said...

Someone else with a Mac came up with this problem. On opening the file, click the clock icon to the left of the timeline. Choose 'one folder at a time' option. Make sure the new file you opened is selected. Should work?

Rich