如何修复Scattergeo Marker Size属性的ValueError错误？

运行地震数据可视化代码时，执行'size': [5*mag for mag in mags]行触发ValueError，提示scattergeo.marker的size属性收到无效负数元素（如-0.35、-1.0等）。尝试用Try/Except语句未解决。

错误信息：

ValueError:
Invalid element(s) received for the 'size' property of scattergeo.marker
Invalid elements include: [-0.35000000000000003, -1.0, -0.8500000000000001, -0.1, -2.5,
-0.05, -2.8000000000000003, -2.75, -3.35, -0.4]

原代码：

import json
from plotly.graph_objs import Scattergeo, Layout
from plotly import offline


# Get a JSON file.
filename = 'earthquake_data/seven_days_earthquake.json'
with open(filename, encoding='utf-8') as f:
    eq_data = json.load(f)

# Create a readable file from the loaded json file above.

readable_file = 'earthquake_data/readable_eq_data.json'
with open(readable_file, 'w') as f:
    json.dump(eq_data, f, indent=4)

# Exploring the structure of the data.
title = eq_data["metadata"]["title"]
all_eq_dicts = eq_data["features"]

mags, lons, lats, hover_texts = [], [], [], []
for eq_dict in all_eq_dicts:
    try:
        mags.append(eq_dict["properties"]["mag"])
        lons.append(eq_dict["geometry"]["coordinates"][0])
        lats.append(eq_dict["geometry"]["coordinates"][1])
        hover_texts.append(eq_dict["properties"]["title"])
    except ValueError:
        print("Data not available.")

# Map the earthquakes.
data = [{
    'type': 'scattergeo',
    'lon': lons,
    'lat': lats,
    'text': hover_texts,

    # Outline marks in the map. 
    'marker': {
        'size': [5*mag for mag in mags],
        'color': mags,
        'colorscale': 'Viridis',
        'reversescale': True,
        'colorbar': {'title': 'Magnitude'},
    },

}]

# One-week Earthquake data output.
my_layout = Layout(title = f'{title}')
fig = {'data': data, 'layout': my_layout}
offline.plot(fig, filename='sevenday_quakes.html')

• 过滤负震级数据：震级为负数属于无效或异常记录，可在收集数据阶段直接排除，保证后续计算的size均为有效值：

  for eq_dict in all_eq_dicts:
      try:
          mag = eq_dict["properties"]["mag"]
          # 仅保留震级≥0的数据
          if mag >= 0:
              mags.append(mag)
              lons.append(eq_dict["geometry"]["coordinates"][0])
              lats.append(eq_dict["geometry"]["coordinates"][1])
              hover_texts.append(eq_dict["properties"]["title"])
          else:
              print(f"Skipping negative magnitude: {mag}")
      except Exception as e:
          print(f"Data not available: {e}")
  

• 修正size计算逻辑：若不想过滤数据，可在生成size列表时将负数转为最小有效正数（避免marker不可见）：

  # 方案1：取震级绝对值计算size
  'size': [5*abs(mag) for mag in mags]
  # 方案2：设置最小size为1，同时保留正震级的比例关系
  'size': [max(5*mag, 1) if mag >=0 else 1 for mag in mags]
  

• 调整异常捕获逻辑：原代码的Try/Except仅捕获ValueError，但负震级数据不会触发该异常，需主动判断震级有效性，而非依赖异常捕获。

内容的提问来源于stack exchange，提问作者Alonskii