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segyio

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segyio - SEG-Y Seismic Data

segyio - SEG-Y地震数据

Quick Reference

快速参考

python
import segyio
python
import segyio

Read

读取

with segyio.open('seismic.sgy', 'r') as f: print(f.tracecount, len(f.samples)) trace0 = f.trace[0] # Single trace as numpy array data = segyio.tools.collect(f.trace[:]) # All traces
with segyio.open('seismic.sgy', 'r') as f: print(f.tracecount, len(f.samples)) trace0 = f.trace[0] # 单个道，格式为numpy数组 data = segyio.tools.collect(f.trace[:]) # 所有道数据

3D access (specify inline/xline byte locations)

3D访问（指定测线/联络测线的字节位置）

with segyio.open('seismic.sgy', 'r', iline=189, xline=193) as f: inline_100 = f.iline[100] # 2D array (xlines x samples) cube = segyio.tools.cube(f) # Full 3D cube
with segyio.open('seismic.sgy', 'r', iline=189, xline=193) as f: inline_100 = f.iline[100] # 二维数组（联络测线 × 采样点） cube = segyio.tools.cube(f) # 完整3D数据体

Write

写入

spec = segyio.spec() spec.samples = samples spec.tracecount = n_traces with segyio.create('output.sgy', spec) as f: f.trace[0] = data
undefined
spec = segyio.spec() spec.samples = samples spec.tracecount = n_traces with segyio.create('output.sgy', spec) as f: f.trace[0] = data
undefined

Key Access Modes

核心访问模式

ModeDescription
f.trace[i]
Sequential trace access by index
f.header[i]
Trace header access (dict-like)
f.iline[n]
Inline slice (3D surveys)
f.xline[n]
Crossline slice (3D surveys)
f.depth_slice[n]
Horizontal time/depth slice
f.text[0]
Text header (3200 bytes)
f.bin
Binary header
模式描述
f.trace[i]
通过索引按顺序访问道数据
f.header[i]
访问道头文件（类字典格式）
f.iline[n]
测线切片（适用于3D勘探数据）
f.xline[n]
联络测线切片（适用于3D勘探数据）
f.depth_slice[n]
水平时间/深度切片
f.text[0]
文本头文件（3200字节）
f.bin
二进制头文件

Essential Operations

关键操作

Open and Inspect

打开与检查

python
with segyio.open('seismic.sgy', 'r') as f:
    print(f"Traces: {f.tracecount}")
    print(f"Samples: {len(f.samples)}")
    print(f"Sample interval: {f.samples[1] - f.samples[0]} ms")
    if f.ilines is not None:
        print(f"Inlines: {f.ilines}")
        print(f"Crosslines: {f.xlines}")
python
with segyio.open('seismic.sgy', 'r') as f:
    print(f"道数量: {f.tracecount}")
    print(f"采样点数量: {len(f.samples)}")
    print(f"采样间隔: {f.samples[1] - f.samples[0]} 毫秒")
    if f.ilines is not None:
        print(f"测线范围: {f.ilines}")
        print(f"联络测线范围: {f.xlines}")

Read Trace Headers

读取道头文件

python
with segyio.open('seismic.sgy', 'r') as f:
    header = f.header[0]
    print(header[segyio.TraceField.INLINE_3D])
    print(header[segyio.TraceField.CDP_X])

    # Get all values for one field
    inlines = f.attributes(segyio.TraceField.INLINE_3D)[:]
python
with segyio.open('seismic.sgy', 'r') as f:
    header = f.header[0]
    print(header[segyio.TraceField.INLINE_3D])
    print(header[segyio.TraceField.CDP_X])

    # 获取单个字段的所有值
    inlines = f.attributes(segyio.TraceField.INLINE_3D)[:]

Read 3D Data

读取3D数据

python
with segyio.open('seismic.sgy', 'r', iline=189, xline=193) as f:
    inline_data = f.iline[100]       # Shape: (n_xlines, n_samples)
    xline_data = f.xline[200]        # Shape: (n_ilines, n_samples)
    time_slice = f.depth_slice[250]  # Shape: (n_ilines, n_xlines)
    cube = segyio.tools.cube(f)      # Shape: (ilines, xlines, samples)
python
with segyio.open('seismic.sgy', 'r', iline=189, xline=193) as f:
    inline_data = f.iline[100]       # 形状: (联络测线数, 采样点数)
    xline_data = f.xline[200]        # 形状: (测线数, 采样点数)
    time_slice = f.depth_slice[250]  # 形状: (测线数, 联络测线数)
    cube = segyio.tools.cube(f)      # 形状: (测线数, 联络测线数, 采样点数)

Read Unstructured Data

读取非结构化数据

python
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python
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For 2D lines or unsorted data

适用于2D测线或未排序的数据

with segyio.open('seismic.sgy', 'r', ignore_geometry=True) as f: data = segyio.tools.collect(f.trace[:])
undefined
with segyio.open('seismic.sgy', 'r', ignore_geometry=True) as f: data = segyio.tools.collect(f.trace[:])
undefined

Create New SEG-Y

创建新的SEG-Y文件

python
import numpy as np

spec = segyio.spec()
spec.samples = np.arange(500) * 4  # 4ms sample rate
spec.tracecount = 100
spec.format = 1  # IBM float

with segyio.create('output.sgy', spec) as f:
    for i in range(100):
        f.trace[i] = data[i]
        f.header[i] = {
            segyio.TraceField.TRACE_SEQUENCE_LINE: i + 1,
        }
python
import numpy as np

spec = segyio.spec()
spec.samples = np.arange(500) * 4  # 4毫秒采样率
spec.tracecount = 100
spec.format = 1  # IBM浮点数

with segyio.create('output.sgy', spec) as f:
    for i in range(100):
        f.trace[i] = data[i]
        f.header[i] = {
            segyio.TraceField.TRACE_SEQUENCE_LINE: i + 1,
        }

Modify Existing File

修改现有文件

python
with segyio.open('seismic.sgy', 'r+') as f:
    f.trace[0] = f.trace[0] * 2.0
    f.header[0][segyio.TraceField.CDP] = 999
python
with segyio.open('seismic.sgy', 'r+') as f:
    f.trace[0] = f.trace[0] * 2.0
    f.header[0][segyio.TraceField.CDP] = 999

Data Formats

数据格式

CodeFormat
1IBM 4-byte float
24-byte signed integer
32-byte signed integer
5IEEE 4-byte float
81-byte signed integer
编码格式
1IBM 4字节浮点数
24字节有符号整数
32字节有符号整数
5IEEE 4字节浮点数
81字节有符号整数

When to Use vs Alternatives

适用场景与替代工具对比

ToolBest For
segyioFast SEG-Y I/O, 3D inline/crossline access, header manipulation
obspyBroader seismology: FDSN access, waveform processing, event analysis
segysakxarray-based SEG-Y workflows, NetCDF conversion, labeled dimensions
Use segyio when you need fast, low-level access to SEG-Y files -- reading traces, headers, 3D slices, or creating new SEG-Y files programmatically.
Use obspy instead when you need seismological processing beyond file I/O: instrument response removal, FDSN data fetching, or earthquake analysis.
Use segysak instead when you want xarray integration with labeled dimensions (inline, crossline, time) and easy conversion to NetCDF/Zarr.
工具最佳适用场景
segyio快速SEG-Y读写、3D测线/联络测线访问、头文件操作
obspy更广泛的地震学应用：FDSN数据访问、波形处理、事件分析
segysak基于xarray的SEG-Y工作流、NetCDF格式转换、带标签维度
当你需要以下操作时使用segyio：快速的底层SEG-Y文件访问——读取道数据、头文件、3D切片，或以编程方式创建新的SEG-Y文件。
当你需要以下操作时改用obspy：除文件读写外的地震学处理，如仪器响应移除、FDSN数据获取或地震分析。
当你需要以下操作时改用segysak：xarray集成、带标签维度（测线、联络测线、时间）以及便捷的NetCDF/Zarr格式转换。

Common Workflows

常见工作流

Read, inspect, and extract 3D seismic data

读取、检查并提取3D地震数据

- [ ] Open file with `segyio.open()`, specify `iline=` and `xline=` byte positions
- [ ] Inspect geometry: trace count, sample count, inline/crossline ranges
- [ ] Read headers to verify coordinate and survey metadata
- [ ] Extract target inline/crossline slices or full cube
- [ ] Apply amplitude scaling or subset extraction as needed
- [ ] Write results to new SEG-Y or export as numpy arrays
- [ ] 使用`segyio.open()`打开文件，指定`iline=`和`xline=`字节位置
- [ ] 检查几何信息：道数量、采样点数量、测线/联络测线范围
- [ ] 读取头文件以验证坐标和勘探元数据
- [ ] 提取目标测线/联络测线切片或完整数据体
- [ ] 根据需要应用振幅缩放或子集提取
- [ ] 将结果写入新SEG-Y文件或导出为numpy数组

Common Issues

常见问题

IssueSolution
Geometry not detectedSpecify 
iline=
and 
xline=
byte positions
Can't read 3D slicesUse 
ignore_geometry=True
for unstructured data
Wrong inline/xline bytesCheck headers with 
f.header[0]
to find correct bytes
File not openingCheck file path, permissions, and SEG-Y format validity
问题解决方案
无法检测几何信息指定
iline=
和
xline=
字节位置
无法读取3D切片对非结构化数据使用
ignore_geometry=True
测线/联络测线字节错误使用
f.header[0]
检查头文件以找到正确的字节位置
文件无法打开检查文件路径、权限和SEG-Y格式有效性

References

参考资料

  • Trace Header Fields - Complete header field reference (bytes, types)
  • Troubleshooting - Common problems and solutions
  • 道头文件字段 - 完整的头文件字段参考（字节位置、类型）
  • 故障排查 - 常见问题及解决方案

Scripts

脚本

  • scripts/inspect_segy.py - Inspect SEG-Y file structure and geometry
  • scripts/extract_subset.py - Extract subset of traces or inlines
  • scripts/inspect_segy.py - 检查SEG-Y文件结构和几何信息
  • scripts/extract_subset.py - 提取道或测线的数据子集