Cost and Pathway, Ex8

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Cost and Pathway, Ex8

• An Example

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The Example

• Use the Window command to make a set of smaller
  images centered on
• Used this to
• Do a pathway through the NIFKIN road network
• Find the length of the pathway
• Based on soils compute the cost of building the
  pathway (road)
• Look at the Inverse distance process

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Cost and pathway
COSTGROW
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Length in feet
Real Bin
1 ? -1
COSTGROW
Real Bin
X 165
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Adding up costs
Converts to -1
To soil
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Costs

• Usually there were be a number of factors that
  enter in the calculation of Friction.
• Thus it is best to normalize the data to some
  fixed value
• Like 30
• Then it is easy to say that each of the factors
  is X of the total friction
• Sometimes you have frictions like
• Stay close to roads
• Stay away from residential properties

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Distance

• Use the distance function to create layers of
  distance from a set of targets
• To make it costly (friction) to stay away from a
  feature just use normalized distance
• To make it costly (friction) to stay away from
  features you have to invert the distance image

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Avoiding

• This is how
• DISTANCE
• - max distance
• ABS

In Transform
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Another way

• DISTANCE
• Normalize by x (30/max value)
• Multiply by 1
• 30

Normalized to 30
X -1
30
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Sub model
This changes pathway to a background of -1 and
converts the image to real. binary
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Invert
30/max
X -1
30
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Normal dist
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Invert dist
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So to get total Friction
F1_Soil
F1_Slope
F1_Roads
F1_LUs

Max Possible 4x30120
F_Total
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Not cross Lake or Wetlands

• How do we prevent COST from crossing these
  landuses?
• Or, put another way, how do we prevent PATHWAY
  from crossing them?
• Use COSTGROW
• Then 1 is a absolute barrier

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Not cross Protected LUs

• Well, same thing
• Make them 1 also
• So we have two images with not crossable areas
  with values of _-1_
• How to combine them? What should the value of
  the crossable areas be?
• That is, where are we going with this?

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Not Cross Protected LUs

• Humm Have to combine the not crossable with
  the Friction layers so that not crossable is
  maintained in the result!
• So we use MINIMUM
• If that is the case then the value of crossable
  areas should be gt200
• But look ahead -----
• What is the total possible in Alternative 2?

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So

• -1 where not crossable
• 200 where crossable

Range is 1 to lt 120
F1_Total
Not_Cross
?
Min
F_Final1
So min will result in file with 1 in uncrossable
areas and total friction in rest of image
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And the Rest is a piece of Cake
F1_Total
Terminal
COST
Cost1
Well
PATHWAY
Path1
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The 2nd Alternative

• If you figure out what has to be done here before
  doing Alternative 2 then you can save yourself
  some time.
• Think it through
• How can you maximize the re-use of layers in 2
  from 1?
• If you make the 1 images have a background of,
  say, 300 or 400 then you can use them in the 2nd
  part.

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How to get Total Cost

• This is How (for three layers) ..

Total per foot of line. But each cell is 165
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1/foot for each 100 feet?

• Distance again
• But /100 to get 100s of feet from road to that
  cell.

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And then

• Duh Multiply the total Cost by the pathway
  image!
• Now count cells of same total cost
• Bummer! ? Lots of work
• Wait there is a better way!!!!!
• Use COSTGROW again!!! WOW!
• But remember to make pathway background 1 !!!!

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The Better Way
TotalCost
Pathway1
Real, Binary w/ -1.0s not 1s
X
Total length of line in cells counting diagonals
in last cell
CostInPath
RECLASS to what?
RECLASS 0? -1
CostCell
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Aaaaaad Theeen
CostCell
Pathway1
X
PathCost
Terminal
And where isTOTALCOST??
COST
AccumCost
In the last cell, Where Else!!!!