How do you make the turtles follow only the green patches that I created from a shapefile Ioaded into netlogo? - gis

Question

This is my code so far. I only want the turtles to follow the green lines, however they just continue forever in the random direction they are facing when I setup the model.
Code:
extensions [gis]
breed [observer]
turtles-own [ vision-distance vision-width steps green-steps gray-steps attr-prob]
patches-own [land nearest-patch]
to setup
clear-all
create-turtles 10
set-default-shape turtles "butterfly"
ask turtles [set size 25
if pxcor = min-pxcor [die]]
reset-ticks
let view gis:load-dataset "City_Plan_Boundary.shp"
gis:set-world-envelope gis:envelope-of view
foreach gis:feature-list-of view
[
gis:set-drawing-color green
gis:draw ? 1.0
]
end
to go
ask turtles [
count-steps
pen-down
let green_target turtles
let perceived_patches patches in-cone vision-distance vision-width
let patch-under-me patch-here set green_target perceived_patches with [ (pcolor = green and self != patch-under-me) or (pcolor = black and self != patch-under-me)]
ifelse count green_target != 0 [
let target min-one-of green_target[ distance myself ]
let target_heading towards target
move-to patch-at-heading-and-distance target_heading 1 ]
[ fd 1]
]
end
to count-steps
set steps steps + 1
ifelse land = green [set green-steps green-steps + 1][set gray-steps gray-steps + 1] ;;Does not currently account for CYAN Park squares
end

Answer 1

First, your foreach loop that applies your GIS layer is only creating lines in the drawing layer of NetLogo, not actually changing the patches themselves. You'll have to assign some component of the shapefile to the patches themselves for turtles to be able to assess them- look at the "GIS General Examples" model in the Models Library.
Second, pathfinding can be accomplished in a variety of ways, and it really depends on what behaviour you're trying to model. For a few examples, check out the "Look Ahead" example in the Models library, or look at the below toy model for a very simplistic approach:
to setup
ca
ask patch min-pxcor 0 [
set pcolor green
sprout 1 [
set color red
pd
]
spread-right
]
reset-ticks
end
to spread-right
if pxcor < max-pxcor [
ask one-of neighbors with [ pxcor = [pxcor] of myself + 1] [
set pcolor green
spread-right
]
]
end
to go
ask turtles [
let target one-of neighbors in-cone 1.5 90 with [ pcolor = green ]
ifelse target != nobody [
face target
move-to target
] [
rt one-of [ 45 -45 ]
]
]
tick
end