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Updated Class 9
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‎Classes/09_Cursors/ALL_FILES.zip‎

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‎Classes/09_Cursors/Step_1.py‎

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print("There are " + str(line_count) + " csv records for crane 100840.")
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# Uncomment the below, now let's now do the same using arcpy.da (arcpy data access module):
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# Uncomment the below, now let's now do the same using arcpy.da (arcpy data access module), you could of course
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# use select and get count but we are doing it the hard way!:
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# import arcpy
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# line_count_da = 0

‎Classes/09_Cursors/Step_1_Answers.py‎

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#
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# print("There are " + str(line_count) + " csv records for crane 100840.")
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# Uncomment the below, now let's now do the same using arcpy.da (arcpy data access module):
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# Uncomment the below, now let's now do the same using arcpy.da (arcpy data access module), you could of course
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# use select and get count but we are doing it the hard way!:
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# import arcpy
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# line_count_da = 0

‎Classes/09_Cursors/Step_4.py‎

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#####
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# Step 4 - Data Access module - Adding new records using an InsertCursor.
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#####
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# Insert Cursors are used to add new data to shapefile or feature class. It is almost exactly the same
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# as the other Cursors that we have used. In this example, we will construct a line feature class.
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import arcpy, os
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from math import radians, sin, cos
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# Create an empty Shapefile
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arcpy.env.workspace = r"C:\Course_ArcGIS_Python\Classes\9_Cursors"
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# Set local variables
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out_path = arcpy.env.workspace
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out_name = "radiating_line.shp"
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geometry_type = "POLYLINE"
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template = "#"
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has_m = "DISABLED"
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has_z = "DISABLED"
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# Use Describe to get a SpatialReference object
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spatial_ref = 4326
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# Execute CreateFeatureclass
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arcpy.CreateFeatureclass_management(out_path, out_name, geometry_type, template,
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has_m, has_z, spatial_ref)
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# From a point (origin), let's create some radiating lines and add them to the new shapefile
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origin_x, origin_y = (-71.42, 41.47)
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distance = 1
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angle = 10 # in degrees
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OutputFeature = os.path.join(out_path, out_name)
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#create list of bearings
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angles = range(0, 360,angle)
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print(angles)
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for ang in angles:
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# calculate offsets with trig
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angle = float(int(ang))
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(disp_x, disp_y) = (distance * sin(radians(angle)), distance * cos(radians(angle)))
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(end_x, end_y) = (origin_x + disp_x, origin_y + disp_y)
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(end2_x, end2_y) = (origin_x + disp_x, origin_y + disp_y)
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cur = arcpy.InsertCursor(OutputFeature)
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lineArray = arcpy.Array()
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# start point
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start = arcpy.Point()
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(start.ID, start.X, start.Y) = (1, origin_x, origin_y)
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lineArray.add(start)
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# end point
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end = arcpy.Point()
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(end.ID, end.X, end.Y) = (2, end_x, end_y)
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lineArray.add(end)
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# write our fancy feature to the shapefile
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feat = cur.newRow()
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feat.shape = lineArray
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cur.insertRow(feat)
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# yes, this shouldn't really be necessary...
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lineArray.removeAll()
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del cur
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# Task - Using the above code, amend it so you can do multiple origin_x and origin_y. Note that you don't have to do
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# too much to the code, so think of the steps you need to take before you touch this. BTW this is a hard one. Use this
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# for your input locations: input_locations = [(-71.42, 41.47), (-72.42, 42.47), (-73.42, 43.47)]
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input_locations = [(-71.42, 41.47), (-72.42, 42.47), (-73.42, 43.47)]
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for location in input_locations:
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location == (-71.42, 41.47)
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location[0] == -71.42
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location[1] == 41.47

‎Classes/09_Cursors/Step_4_Answers.py‎

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#####
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# Step 4 - Data Access module - Adding new records using an InsertCursor.
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#####
4+
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# Insert Cursors are used to add new data to shapefile or feature class. It is almost exactly the same
6+
# as the other Cursors that we have used. In this example, we will construct a line feature class.
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import arcpy, os
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from math import radians, sin, cos
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# # Create an empty Shapefile
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# arcpy.env.workspace = r"C:\Course_ArcGIS_Python\Classes\9_Cursors"
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#
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# # Set local variables
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# out_path = arcpy.env.workspace
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# out_name = "radiating_line.shp"
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# geometry_type = "POLYLINE"
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# template = "#"
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# has_m = "DISABLED"
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# has_z = "DISABLED"
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#
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# # Use Describe to get a SpatialReference object
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# spatial_ref = 4326
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#
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# # Execute CreateFeatureclass
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# arcpy.CreateFeatureclass_management(out_path, out_name, geometry_type, template,
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# has_m, has_z, spatial_ref)
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#
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#
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# # From a point (origin), let's create some radiating lines and add them to the new shapefile
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#
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# origin_x, origin_y = (-71.42, 41.47)
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# distance = 1
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# angle = 10 # in degrees
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#
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# OutputFeature = os.path.join(out_path, out_name)
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#
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# #create list of bearings
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# angles = range(0, 360,angle)
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#
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#
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# for ang in angles:
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# # calculate offsets with trig
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# angle = float(int(ang))
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# (disp_x, disp_y) = (distance * sin(radians(angle)), distance * cos(radians(angle)))
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# (end_x, end_y) = (origin_x + disp_x, origin_y + disp_y)
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# (end2_x, end2_y) = (origin_x + disp_x, origin_y + disp_y)
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#
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# cur = arcpy.InsertCursor(OutputFeature)
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# lineArray = arcpy.Array()
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#
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# # start point
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# start = arcpy.Point()
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# (start.ID, start.X, start.Y) = (1, origin_x, origin_y)
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# lineArray.add(start)
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#
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# # end point
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# end = arcpy.Point()
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# (end.ID, end.X, end.Y) = (2, end_x, end_y)
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# lineArray.add(end)
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#
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# # write our fancy feature to the shapefile
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# feat = cur.newRow()
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# feat.shape = lineArray
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# cur.insertRow(feat)
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#
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# # yes, this shouldn't really be necessary...
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# lineArray.removeAll()
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# del cur
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# Task - Using the above code, amend it so you can do multiple origin_x and origin_y. Note that you don't have to do
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# too much to the code, so think of the steps you need to take before you touch this. BTW this is a hard one. Use this
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# for your input locations: input_locations = [(-71.42, 41.47), (-72.42, 42.47), (-73.42, 43.47)]
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import arcpy, os
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from math import radians, sin, cos
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# Create an empty Shapefile
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arcpy.env.workspace = r"C:\Course_ArcGIS_Python\Classes\9_Cursors"
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# Set local variables
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out_path = arcpy.env.workspace
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out_name = "radiating_line_2.shp"
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geometry_type = "POLYLINE"
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template = "#"
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has_m = "DISABLED"
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has_z = "DISABLED"
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# Use Describe to get a SpatialReference object
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spatial_ref = 4326
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# Execute CreateFeatureclass
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arcpy.CreateFeatureclass_management(out_path, out_name, geometry_type, template,
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has_m, has_z, spatial_ref)
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input_locations = [(-71.42, 41.47), (-72.42, 42.47), (-73.42, 43.47)]
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for i in input_locations:
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origin_x, origin_y = i[0], i[1]
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distance = 1
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angle = 10 # in degrees
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OutputFeature = os.path.join(out_path, out_name)
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#create list of bearings
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angles = range(0, 360,angle)
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for ang in angles:
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# calculate offsets with trig
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angle = float(int(ang))
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(disp_x, disp_y) = (distance * sin(radians(angle)), distance * cos(radians(angle)))
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(end_x, end_y) = (origin_x + disp_x, origin_y + disp_y)
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(end2_x, end2_y) = (origin_x + disp_x, origin_y + disp_y)
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cur = arcpy.InsertCursor(OutputFeature)
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lineArray = arcpy.Array()
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# start point
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start = arcpy.Point()
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(start.ID, start.X, start.Y) = (1, origin_x, origin_y)
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lineArray.add(start)
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# end point
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end = arcpy.Point()
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(end.ID, end.X, end.Y) = (2, end_x, end_y)
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lineArray.add(end)
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# write our fancy feature to the shapefile
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feat = cur.newRow()
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feat.shape = lineArray
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cur.insertRow(feat)
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# yes, this shouldn't really be necessary...
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lineArray.removeAll()
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del cur

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