topic Re: Looping through XYZ coordinats in Python Questions

Looping through XYZ coordinats

Daniel4 — Mon, 25 Apr 2022 20:34:07 GMT

Hi, I working on a road dataset and found all the roads that intersect, like the to roads below:

I want to investigate if the z-value from the two roads are the same. I used arcpy.FeatureVerticesToPoints_management the get the XYZ values from each road, and load them into two python list, like in the example below:

road1 = [(1,2,3),(3,4,5),(4,6,8)]
road2 = [(3,4,6),(1,2,4),(4,5,3)]

The first think I want to do, is to check whatever the roads share vertices (Same XY value) and if the do, whats the difference in their z-value.

I tried with this function:

def compareLineVertiex(list_orginid,list_destid):
sameXY = []
for (x,y,z) in list_orginid:
xy = x,y
if xy in list_destid:

sameXY.append(xyz)
return sameXY

I only managed to compare their XY values. I am missing the z-value (which will be difference from the two list)

Re: Looping through XYZ coordinats

EricEagle — Mon, 25 Apr 2022 21:11:23 GMT

Maybe a little long but how's this

def compare_vertices(linea, lineb): matches = [] for i_idx, a in enumerate(linea): for b_idx, b in enumerate(lineb): if [a[0], a[1]] == [b[0], b[1]]: if a[2] - b[2] > 0: zdiff = a[2] - b[2] else: zdiff = b[2] - a[2] matches.append({ "Point A": { "XYZ": a, "Index": a_idx, }, "Point B": { "XYZ": b, "Index": b_idx, }, "Z diff": zdiff }) return matches road1 = [(1, 2, 3), (3, 4, 5), (4, 6, 8)] road2 = [(3, 4, 6), (1, 2, 4), (4, 5, 3)] x = compare_vertices(road1, road2) for i in x: print(i) {'Point A': {'XYZ': (1, 2, 3), 'Index': 0}, 'Point B': {'XYZ': (1, 2, 4), 'Index': 1}, 'Z diff': 1} {'Point A': {'XYZ': (3, 4, 5), 'Index': 1}, 'Point B': {'XYZ': (3, 4, 6), 'Index': 0}, 'Z diff': 1}

I only enumerated to know where the points are that match in the array, and returned as a dict because I'm fussy like that and want more info than less usually

Re: Looping through XYZ coordinats

DanPatterson — Tue, 26 Apr 2022 00:09:58 GMT

numpy anyone?

road1 = np.array([(1, 2, 3), (3, 4, 5), (4, 6, 8)]) road2 = np.array([(3, 4, 6), (1, 2, 4), (4, 5, 3)]) xyz = [] for row in road1: x, y, z1 = row chk = (road2[:, :2][:, None] == row[:2]).all(-1) if chk.any(): w = np.nonzero(chk)[0] z2 = road2[w].squeeze() vals = [x, y, z1, z2[-1]] xyz.append(vals) xyz1z2 = np.array(xyz) xyz1z2 array([[1, 2, 3, 4], [3, 4, 5, 6]])

To bring it back into Pro

dt = [('X', 'f8'), ('Y', 'f8'), ('Z1', 'f8'), ('Z2', 'f8')] # -- do it the slow way out = np.zeros(xyz1z2.shape[0], dtype=dt) out['X'] = xyz1z2[:, 0] out['Y'] = xyz1z2[:, 1] out['Z1'] = xyz1z2[:, 2] out['Z2'] = xyz1z2[:, 3] out array([( 1.00, 2.00, 3.00, 4.00), ( 3.00, 4.00, 5.00, 6.00)], dtype=[('X', '<f8'), ('Y', '<f8'), ('Z1', '<f8'), ('Z2', '<f8')]) # --- then arcpy.da.NumPyArrayToTable(out, path_and_tbl_name)

Re: Looping through XYZ coordinats

Daniel4 — Tue, 26 Apr 2022 13:52:06 GMT

Thanks 🙂 this well get the job done. I did a test and its working on the dataset.

Re: Looping through XYZ coordinats

Daniel4 — Tue, 26 Apr 2022 13:55:21 GMT

Thanks 🙂 I will try it out.