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cut small isochrones from the map
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Helena Mitasova authored and Helena Mitasova committed Sep 22, 2024
1 parent ea30eae commit 46aea60
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31 changes: 15 additions & 16 deletions grass/buffers_cost.html
Original file line number Diff line number Diff line change
Expand Up @@ -64,7 +64,7 @@ <h4>Find developed areas potentially impacted by noise from highways</h4>
</code></pre>

<span class="question">What is the total developed area iin [ha]
within the 150m from the major roads?</span>
within the 250m from the major roads?</span>

<h4>Find schools potentially affected by high levels of noise</h4>
Convert schools to raster using CORECAPACI attribute (school capacity).<br>
Expand Down Expand Up @@ -99,7 +99,7 @@ <h4>Compute cumulative cost surface to a given accident site based on speed limi
v.to.rast streets_wake output=streets_speedtmp use=attr attrcolumn=SPEED type=line
r.mapcalc "streets_speed = if(isnull(streets_speedtmp),5,streets_speedtmp)"
r.info streets_speed
r.colors streets_speed color=gyr
r.colors streets_speed color=inferno
d.rast streets_speed
d.legend streets_speed at=5,40,2,5 use=5,25,35,45,65
d.out.file myspeedmap
Expand Down Expand Up @@ -128,7 +128,6 @@ <h4>Compute cumulative cost surface to a given accident site based on speed limi
r.cost -k streets_travtime output=streets_cost start_points=fire_pt
</code></pre>


<p>
<!-- <font color="#000066">
# or use echo in linux shell
Expand All @@ -137,7 +136,7 @@ <h4>Compute cumulative cost surface to a given accident site based on speed limi
Compute isochrones and display the cumulative cost surface map.

<pre><code>
r.contour streets_cost output=streets_cost_04 step=0.04
r.contour streets_cost output=streets_cost_04 step=0.04 cut=100
r.colors streets_cost color=elevation
d.rast streets_cost
d.vect fire_pt color=red icon=basic/marker size=20
Expand All @@ -156,6 +155,7 @@ <h4>Find cost (travel time) from selected firestations</h4>
g.copy vector=firestations,myfirestations
v.info -c myfirestations
v.what.rast myfirestations raster=streets_cost column=CVLAG
d.vect myfirestations icon=basic/circle size=15 fill_color=red
</code></pre>

<p>
Expand Down Expand Up @@ -206,6 +206,7 @@ <h4>Find cost (travel time) from selected firestations</h4>
d.erase
d.rast streets_cost
d.vect fire_pt color=red icon=basic/marker size=20
d.vect myfirestations icon=basic/circle size=15 fill_color=red
d.rast route_20Westernb
d.rast route_52Hollyb
d.out.file mylcpmap
Expand Down Expand Up @@ -258,14 +259,15 @@ <h4>Compute accessibility map for help in search for lost person</h4>
d.erase
d.rast friction2
d.legend friction2 at=5,50,2,5
d.out.file myfrictionmap
</code></pre>

<p>
Compute the cost map and generate isochrones:

<pre><code>
r.walk -k elevation=elev_ned_30m friction=friction2 output=walkcost start_coordinates=635576,216485 lambda=0.5 max_cost=10000
r.contour walkcost output=walkcost step=1000
r.contour walkcost output=walkcost step=1000 cut=100
</code></pre>

<p>
Expand Down Expand Up @@ -296,15 +298,6 @@ <h4>Compute accessibility map for help in search for lost person</h4>
d.out.file mywalkcostmap
</code></pre>

<h4>Cost surfaces to line features</h4>
Compute the shortest distance to a major road.<br>
Set region, convert vector road map to raster:

<pre><code>
g.region swwake_30m -p
v.to.rast roadsmajor output=roadsmajor use=val type=line
</code></pre>

<h3>Optional</h3>

<h4>Find developed areas close to lakes</h4>
Expand Down Expand Up @@ -349,7 +342,14 @@ <h4>Find developed areas close to lakes</h4>
r.report -n developed_lake units=h
</code></pre>

<h4> Compute the distance map and cost surface to highways</h4>:
<h4> Compute the shortest distance map and cost surface to highways</h4>:

Set region, convert vector road map to raster:

<pre><code>
g.region swwake_30m -p
v.to.rast roadsmajor output=roadsmajor use=val type=line
</code></pre>

<pre><code>
r.mapcalc "area_one = 1"
Expand All @@ -369,7 +369,6 @@ <h4> Compute the distance map and cost surface to highways</h4>:
d.out.file cost_roadsmaj
</code></pre>


<!---
# compute linear regression and correlation coefficient between different elevation data
r.regression.line elevation map2=elev_srtm_30m
Expand Down

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