diff --git a/src/core/algo/GeoVolumeBuilder.cpp b/src/core/algo/GeoVolumeBuilder.cpp
new file mode 100644
index 0000000..2e09313
--- /dev/null
+++ b/src/core/algo/GeoVolumeBuilder.cpp
@@ -0,0 +1,335 @@
+// GeoVolumeBuilder：按真实 RTK 几何把多条测线插值进统一路向网格。
+//
+// 编排层（io_gpr + core 采样核 + store），故与 StreamingVolumeBuilder 一样编进
+// geopro_store（不污染纯 geopro_core）。命名空间保持 geopro::core（接口契约）。
+#include "core/algo/GeoVolumeBuilder.hpp"
+
+#include <algorithm>
+#include <array>
+#include <cmath>
+#include <cstdint>
+#include <filesystem>
+#include <fstream>
+#include <iterator>
+#include <limits>
+#include <stdexcept>
+#include <vector>
+
+#include "core/algo/GprVolumeBuilder.hpp"  // BuiltI16
+#include "core/model/ScalarVolumeI16.hpp"  // ScalarVolumeI16::kBlank, Quant
+#include "data/store/ChunkedVolumeStore.hpp"
+#include "io/gpr/GprGeometry.hpp"  // parseChannelXOffsets, depthOfSample
+#include "io/gpr/GpsTrack.hpp"
+#include "io/gpr/IprHeader.hpp"
+#include "io/gpr/IprbReader.hpp"
+
+namespace fs = std::filesystem;
+
+namespace geopro::core {
+
+namespace {
+
+constexpr double kPi = 3.14159265358979323846;
+
+// 读 .iprh 文本 → 解析头（与 .iprb 同名）。
+geopro::io::gpr::IprHeader readHeaderFor(const std::string& iprbPath) {
+  fs::path h = fs::path(iprbPath).replace_extension(".iprh");
+  std::ifstream f(h);
+  if (!f) throw std::runtime_error("GeoVolumeBuilder: 打不开 iprh " + h.string());
+  std::string text((std::istreambuf_iterator<char>(f)),
+                   std::istreambuf_iterator<char>());
+  return geopro::io::gpr::parseIprHeader(text);
+}
+
+// 一条线的标尺（轨迹局部米 + 通道横偏 + 头）。
+struct LineScale {
+  std::vector<geopro::io::gpr::XY> trackM;  // 该线轨迹（局部米，旋转前）
+  std::vector<double> chanX;                // 通道横偏（米，文件顺序）
+  geopro::io::gpr::IprHeader header;
+  std::int64_t totalTraces = 0;
+};
+
+// 全线总道数 = min 通道(fileBytes/(samples*2))（与 assembler 口径一致）。
+std::int64_t totalTracesOf(const std::vector<std::string>& iprb, int samples) {
+  std::int64_t minTr = std::numeric_limits<std::int64_t>::max();
+  const std::int64_t per = static_cast<std::int64_t>(samples) * 2;
+  if (per <= 0) throw std::runtime_error("samples<=0");
+  for (const auto& p : iprb) {
+    const std::int64_t bytes = static_cast<std::int64_t>(fs::file_size(p));
+    minTr = std::min(minTr, bytes / per);
+  }
+  return minTr;
+}
+
+}  // namespace
+
+// ---- PCA 主轴角（可测纯函数）----
+double principalAxisAngle(const std::vector<double>& xs,
+                          const std::vector<double>& ys) {
+  const std::size_t n = std::min(xs.size(), ys.size());
+  if (n < 2) return 0.0;
+
+  double mx = 0, my = 0;
+  for (std::size_t i = 0; i < n; ++i) {
+    mx += xs[i];
+    my += ys[i];
+  }
+  mx /= static_cast<double>(n);
+  my /= static_cast<double>(n);
+
+  double sxx = 0, syy = 0, sxy = 0;
+  for (std::size_t i = 0; i < n; ++i) {
+    const double dx = xs[i] - mx, dy = ys[i] - my;
+    sxx += dx * dx;
+    syy += dy * dy;
+    sxy += dx * dy;
+  }
+  sxx /= static_cast<double>(n);
+  syy /= static_cast<double>(n);
+  sxy /= static_cast<double>(n);
+
+  // 2×2 对称协方差矩阵最大特征向量方向 = 0.5*atan2(2*sxy, sxx-syy)。
+  if (std::abs(sxy) < 1e-15 && std::abs(sxx - syy) < 1e-15) return 0.0;
+  return 0.5 * std::atan2(2.0 * sxy, sxx - syy);
+}
+
+GeoBuildResult buildGeoVolume(const std::vector<GeoLineInput>& lines,
+                             const GeoGridSpec& spec,
+                             const std::string& outStoreDir,
+                             int pyramidLevels) {
+  using geopro::io::gpr::interpAlongTrack;
+  using geopro::io::gpr::lonLatToLocalM;
+  using geopro::io::gpr::PosHeading;
+  using geopro::io::gpr::XY;
+
+  if (lines.empty()) throw std::runtime_error("buildGeoVolume: 无测线");
+  if (spec.cellXY <= 0 || spec.cellZ <= 0)
+    throw std::runtime_error("buildGeoVolume: cell 必须 > 0");
+
+  // ---- 1) 各线 .gps → 局部米（共用原点 = 全体最小 lat/lon）----
+  std::vector<geopro::io::gpr::GpsTrack> tracks(lines.size());
+  double minLat = std::numeric_limits<double>::infinity();
+  double minLon = std::numeric_limits<double>::infinity();
+  for (std::size_t i = 0; i < lines.size(); ++i) {
+    tracks[i] = geopro::io::gpr::parseGps(lines[i].gps);
+    for (const auto& p : tracks[i].pts) {
+      minLat = std::min(minLat, p.lat);
+      minLon = std::min(minLon, p.lon);
+    }
+  }
+  if (!std::isfinite(minLat) || !std::isfinite(minLon))
+    throw std::runtime_error("buildGeoVolume: 轨迹为空");
+
+  // 各线标尺：轨迹局部米 + 通道横偏 + 头 + 总道数。
+  std::vector<LineScale> scales(lines.size());
+  int samples = 0;
+  geopro::io::gpr::IprHeader hdr0{};
+  for (std::size_t i = 0; i < lines.size(); ++i) {
+    LineScale& sc = scales[i];
+    sc.trackM.reserve(tracks[i].pts.size());
+    for (const auto& p : tracks[i].pts)
+      sc.trackM.push_back(lonLatToLocalM(p.lat, p.lon, minLat, minLon));
+
+    std::ifstream ordF(lines[i].ord);
+    if (!ordF) throw std::runtime_error("buildGeoVolume: 打不开 ord " + lines[i].ord);
+    std::string ordText((std::istreambuf_iterator<char>(ordF)),
+                        std::istreambuf_iterator<char>());
+    sc.chanX = geopro::io::gpr::parseChannelXOffsets(ordText);
+
+    if (lines[i].iprb.empty())
+      throw std::runtime_error("buildGeoVolume: 线无 iprb");
+    sc.header = readHeaderFor(lines[i].iprb.front());
+    sc.totalTraces = totalTracesOf(lines[i].iprb, sc.header.samples);
+    if (i == 0) {
+      samples = sc.header.samples;
+      hdr0 = sc.header;
+    }
+  }
+  if (samples <= 0) throw std::runtime_error("buildGeoVolume: samples<=0");
+
+  // ---- 2) PCA 求路向主轴角，旋转使路向 = X'、横路 = Y' ----
+  // 收集全体通道平面点（trace 位置 + 通道横偏）求主轴。
+  std::vector<double> px, py;
+  for (std::size_t i = 0; i < scales.size(); ++i) {
+    const LineScale& sc = scales[i];
+    const std::int64_t nt = sc.totalTraces;
+    if (nt < 1 || sc.trackM.size() < 2) continue;
+    // 稀疏采样道（每线最多 ~200 个采样点）求 PCA，省内存。
+    const std::int64_t stride = std::max<std::int64_t>(1, nt / 200);
+    for (std::int64_t t = 0; t < nt; t += stride) {
+      const double frac = nt > 1 ? static_cast<double>(t) / (nt - 1) : 0.0;
+      PosHeading ph = interpAlongTrack(sc.trackM, frac);
+      px.push_back(ph.pos.x);
+      py.push_back(ph.pos.y);
+    }
+  }
+  const double rotRad = principalAxisAngle(px, py);
+  const double cosR = std::cos(-rotRad), sinR = std::sin(-rotRad);
+  auto rotate = [&](double x, double y, double& rx, double& ry) {
+    rx = x * cosR - y * sinR;
+    ry = x * sinR + y * cosR;
+  };
+
+  // ---- 求旋转后包围盒（含通道横偏）→ 网格维度 + 原点 ----
+  double minX = std::numeric_limits<double>::infinity();
+  double minY = std::numeric_limits<double>::infinity();
+  double maxX = -std::numeric_limits<double>::infinity();
+  double maxY = -std::numeric_limits<double>::infinity();
+  for (std::size_t i = 0; i < scales.size(); ++i) {
+    const LineScale& sc = scales[i];
+    const std::int64_t nt = sc.totalTraces;
+    if (nt < 1 || sc.trackM.size() < 2 || sc.chanX.empty()) continue;
+    const std::int64_t stride = std::max<std::int64_t>(1, nt / 200);
+    for (std::int64_t t = 0; t < nt; t += stride) {
+      const double frac = nt > 1 ? static_cast<double>(t) / (nt - 1) : 0.0;
+      PosHeading ph = interpAlongTrack(sc.trackM, frac);
+      const double perpX = -ph.hy, perpY = ph.hx;  // 垂直航向（左法向）
+      for (double oc : {sc.chanX.front(), sc.chanX.back()}) {
+        const double cx = ph.pos.x + oc * perpX;
+        const double cy = ph.pos.y + oc * perpY;
+        double rx, ry;
+        rotate(cx, cy, rx, ry);
+        minX = std::min(minX, rx);
+        maxX = std::max(maxX, rx);
+        minY = std::min(minY, ry);
+        maxY = std::max(maxY, ry);
+      }
+    }
+  }
+  if (!std::isfinite(minX)) throw std::runtime_error("buildGeoVolume: 无有效几何");
+
+  // 深度范围：用首线头取最深样本深度。
+  const double maxDepth = geopro::io::gpr::depthOfSample(samples - 1, hdr0);
+
+  auto cells = [](double range, double cell) {
+    if (cell <= 0.0 || range <= 0.0) return 1;
+    return static_cast<int>(std::ceil(range / cell)) + 1;
+  };
+  const int nx = cells(maxX - minX, spec.cellXY);  // 沿路（长轴 X'）
+  const int ny = cells(maxY - minY, spec.cellXY);  // 横路 Y'
+  const int nz = cells(maxDepth, spec.cellZ);      // 深度 Z
+
+  const std::size_t cellCount =
+      static_cast<std::size_t>(nx) * ny * nz;
+
+  // ---- 3) 逐线逐道逐通道逐样本 → grid sum/count（重叠均值）----
+  std::vector<double> sum(cellCount, 0.0);
+  std::vector<std::uint16_t> cnt(cellCount, 0);
+
+  auto cellIdx = [&](int gi, int gj, int gk) -> std::size_t {
+    return (static_cast<std::size_t>(gk) * ny + gj) * nx + gi;
+  };
+
+  constexpr std::int64_t kChunk = 256;  // 逐线分段读道，内存有界
+  double vmin = std::numeric_limits<double>::infinity();
+  double vmax = -std::numeric_limits<double>::infinity();
+
+  for (std::size_t i = 0; i < scales.size(); ++i) {
+    const LineScale& sc = scales[i];
+    const std::int64_t nt = sc.totalTraces;
+    if (nt < 1 || sc.trackM.size() < 2 || sc.chanX.empty()) continue;
+    const int nChan = static_cast<int>(sc.chanX.size());
+
+    // 各通道 .iprb 区间读（与 chanX 文件顺序对齐：iprb[c] ↔ chanX[c]）。
+    const auto& iprbPaths = lines[i].iprb;
+    if (static_cast<int>(iprbPaths.size()) != nChan) {
+      // 通道数与 .ord 有效通道不一致：按较小者对齐，避免越界。
+    }
+    const int useChan = std::min<int>(nChan, static_cast<int>(iprbPaths.size()));
+
+    for (std::int64_t t0 = 0; t0 < nt; t0 += kChunk) {
+      const std::int64_t t1 = std::min(nt, t0 + kChunk);
+      // 逐通道读该道段。
+      std::vector<geopro::io::gpr::BScan> bs(useChan);
+      for (int c = 0; c < useChan; ++c)
+        bs[c] = geopro::io::gpr::readIprbRange(iprbPaths[c], sc.header, t0, t1);
+
+      for (std::int64_t t = t0; t < t1; ++t) {
+        const double frac = nt > 1 ? static_cast<double>(t) / (nt - 1) : 0.0;
+        PosHeading ph = interpAlongTrack(sc.trackM, frac);
+        const double perpX = -ph.hy, perpY = ph.hx;
+        const std::int64_t lt = t - t0;  // BScan 内局部道索引
+
+        for (int c = 0; c < useChan; ++c) {
+          const double oc = sc.chanX[c];
+          const double cx = ph.pos.x + oc * perpX;
+          const double cy = ph.pos.y + oc * perpY;
+          double rx, ry;
+          rotate(cx, cy, rx, ry);
+          const int gi = static_cast<int>(std::lround((rx - minX) / spec.cellXY));
+          const int gj = static_cast<int>(std::lround((ry - minY) / spec.cellXY));
+          if (gi < 0 || gi >= nx || gj < 0 || gj >= ny) continue;
+
+          for (int s = 0; s < samples; ++s) {
+            const double depth = geopro::io::gpr::depthOfSample(s, sc.header);
+            const int gk = static_cast<int>(std::lround(depth / spec.cellZ));
+            if (gk < 0 || gk >= nz) continue;
+            const double v = static_cast<double>(
+                bs[c].data[static_cast<std::size_t>(lt) * samples + s]);
+            const std::size_t idx = cellIdx(gi, gj, gk);
+            sum[idx] += v;
+            ++cnt[idx];
+          }
+        }
+      }
+    }
+  }
+
+  // ---- 4) 均值 + 求值域 ----
+  std::int64_t filled = 0;
+  for (std::size_t idx = 0; idx < cellCount; ++idx) {
+    if (cnt[idx] == 0) continue;
+    const double mean = sum[idx] / cnt[idx];
+    sum[idx] = mean;  // 复用 sum 存均值
+    vmin = std::min(vmin, mean);
+    vmax = std::max(vmax, mean);
+    ++filled;
+  }
+  if (!(vmin <= vmax)) {
+    vmin = 0.0;
+    vmax = 0.0;
+  }
+
+  // ---- 5) 量化 + 写 store + 金字塔 ----
+  Quant quant;
+  quant.scale = (vmax > vmin) ? (vmax - vmin) / 64000.0 : 1.0;
+  quant.offset = 0.5 * (vmin + vmax);
+
+  ScalarVolumeI16 vol(nx, ny, nz);
+  for (int gk = 0; gk < nz; ++gk)
+    for (int gj = 0; gj < ny; ++gj)
+      for (int gi = 0; gi < nx; ++gi) {
+        const std::size_t idx = cellIdx(gi, gj, gk);
+        vol.at(gi, gj, gk) = (cnt[idx] == 0)
+                                 ? ScalarVolumeI16::kBlank
+                                 : quant.toQ(sum[idx]);
+      }
+
+  BuiltI16 built;
+  built.vol = std::move(vol);
+  built.quant = quant;
+  built.origin = {minX, minY, 0.0};
+  built.spacing = {spec.cellXY, spec.cellXY, spec.cellZ};
+  built.vminPhys = vmin;
+  built.vmaxPhys = vmax;
+
+  fs::create_directories(outStoreDir);
+  geopro::data::ChunkedVolumeStore::write(outStoreDir, built);
+  if (pyramidLevels > 0) {
+    geopro::data::ChunkedVolumeStore store(outStoreDir);
+    store.buildPyramid(pyramidLevels);
+  }
+
+  GeoBuildResult r;
+  r.nx = nx;
+  r.ny = ny;
+  r.nz = nz;
+  r.oxM = minX;
+  r.oyM = minY;
+  r.rotRad = rotRad;
+  r.filled = filled;
+  r.total = static_cast<std::int64_t>(cellCount);
+  return r;
+}
+
+}  // namespace geopro::core
diff --git a/src/core/algo/GeoVolumeBuilder.hpp b/src/core/algo/GeoVolumeBuilder.hpp
new file mode 100644
index 0000000..10babbf
--- /dev/null
+++ b/src/core/algo/GeoVolumeBuilder.hpp
@@ -0,0 +1,57 @@
+#ifndef GEOPRO_CORE_ALGO_GEOVOLUMEBUILDER_HPP
+#define GEOPRO_CORE_ALGO_GEOVOLUMEBUILDER_HPP
+
+#include <cstdint>
+#include <string>
+#include <vector>
+
+namespace geopro::core {
+
+// 统一路向网格规格：横向(X'沿路 / Y'横路)cell = cellXY，深度 cell = cellZ。
+struct GeoGridSpec {
+  double cellXY = 0.5;  // 米
+  double cellZ = 0.1;   // 米
+};
+
+// 一组二维路向点的主成分朝向（协方差最大特征向量），用于把路向对齐到网格长轴 X'。
+// 返回主轴方向角 rotRad（弧度，相对东向 +X），调用方旋转 -rotRad 使路向 → X'。
+// 点少于 2 / 退化（零方差）→ 返回 0。
+double principalAxisAngle(const std::vector<double>& xs,
+                          const std::vector<double>& ys);
+
+// 真实数据建体的产物指标（维度/原点/旋转角/填充率）。
+struct GeoBuildResult {
+  int nx = 0, ny = 0, nz = 0;
+  double oxM = 0, oyM = 0;       // 旋转后网格原点（路向坐标系，米）
+  double rotRad = 0;            // 路向主轴角（弧度，East 起算）
+  std::int64_t filled = 0;     // 非空 cell 数
+  std::int64_t total = 0;      // 总 cell 数
+};
+
+// 一条线的输入文件束（各通道 .iprb 已按通道号排序 + 该线 .ord + .gps）。
+// .iprh 与每个 .iprb 同目录同名（扩展名替换为 .iprh），由读取层自行推导。
+struct GeoLineInput {
+  std::vector<std::string> iprb;  // 该线 14 通道 .iprb（按通道号升序）
+  std::string ord;                // 该线 .ord（通道横偏）
+  std::string gps;                // 该线 .gps（RTK 轨迹）
+};
+
+// 把多条测线按各自真实 RTK 几何插值进一个统一路向网格，重叠 cell 取均值，
+// 量化为 int16 写 ChunkedVolumeStore + 金字塔。
+//
+// 步骤：
+//   1) 各线 .gps → 经纬，全体共用原点(最小 lat/lon) → 局部米；
+//   2) PCA 求路向主轴角 rotRad，旋转使路向 = X'、横路 = Y'；Z = 深度；
+//   3) 每线逐道(里程均匀分布插值定位)逐通道(横偏垂直航向摆放)逐样本 → 网格 cell，
+//      累加 sum + count；
+//   4) 空 cell = blank；非空 = sum/count 均值；
+//   5) 扫值域定 Quant(offset=中点)，量化写 store + buildPyramid。
+//
+// 内存有界：逐线流式读道(readIprbRange 区间)，只持 grid 的 sum/count 累加缓冲。
+GeoBuildResult buildGeoVolume(const std::vector<GeoLineInput>& lines,
+                             const GeoGridSpec& spec,
+                             const std::string& outStoreDir, int pyramidLevels);
+
+}  // namespace geopro::core
+
+#endif  // GEOPRO_CORE_ALGO_GEOVOLUMEBUILDER_HPP
diff --git a/src/data/store/CMakeLists.txt b/src/data/store/CMakeLists.txt
index ab139b5..9c16f22 100644
--- a/src/data/store/CMakeLists.txt
+++ b/src/data/store/CMakeLists.txt
@@ -6,7 +6,10 @@ find_package(Qt6 COMPONENTS Core REQUIRED)
 add_library(geopro_store STATIC
   ChunkedVolumeStore.cpp
   # 流式建体（B4）：编排 io_gpr+core+store，沿 X 分 slab 建 level0 体（命名空间 geopro::data）。
-  ${CMAKE_CURRENT_SOURCE_DIR}/../StreamingVolumeBuilder.cpp)
+  ${CMAKE_CURRENT_SOURCE_DIR}/../StreamingVolumeBuilder.cpp
+  # build-geo（G1）：按真实 RTK 几何把多线插值进统一路向网格（命名空间 geopro::core，
+  # 文件物理位于 src/core/algo/，但编排 io_gpr+core+store 故编进 store，不污染纯 core）。
+  ${CMAKE_SOURCE_DIR}/src/core/algo/GeoVolumeBuilder.cpp)
 
 # include 根 = src/，使 #include "data/store/..." 与 "core/algo/..." 可解析
 # （geopro_tests 链 geopro_store 后透传）。
diff --git a/src/io/gpr/CMakeLists.txt b/src/io/gpr/CMakeLists.txt
index a66381b..e670c63 100644
--- a/src/io/gpr/CMakeLists.txt
+++ b/src/io/gpr/CMakeLists.txt
@@ -1,5 +1,6 @@
 add_library(geopro_io_gpr STATIC
-  IprHeader.cpp IprbReader.cpp GprGeometry.cpp GprSurveyAssembler.cpp)
+  IprHeader.cpp IprbReader.cpp GprGeometry.cpp GprSurveyAssembler.cpp
+  GpsTrack.cpp)
 target_include_directories(geopro_io_gpr PUBLIC ${CMAKE_SOURCE_DIR}/src)
 target_compile_features(geopro_io_gpr PUBLIC cxx_std_17)
 # GprSurveyAssembler 返回 geopro::core::GprSurvey（头文件内联，仅需 include 解析）。
diff --git a/src/io/gpr/GpsTrack.cpp b/src/io/gpr/GpsTrack.cpp
new file mode 100644
index 0000000..fd00805
--- /dev/null
+++ b/src/io/gpr/GpsTrack.cpp
@@ -0,0 +1,109 @@
+#include "io/gpr/GpsTrack.hpp"
+
+#include <cmath>
+#include <fstream>
+#include <sstream>
+#include <stdexcept>
+
+namespace geopro::io::gpr {
+
+namespace {
+constexpr double kMetersPerDegLat = 111320.0;
+constexpr double kPi = 3.14159265358979323846;
+
+// 严格把整列解析为 double；失败返回 false（不抛，供逐行容错跳过）。
+bool parseDouble(const std::string& s, double& out) {
+  try {
+    std::size_t used = 0;
+    out = std::stod(s, &used);
+    return used == s.size();
+  } catch (...) {
+    return false;
+  }
+}
+}  // namespace
+
+GpsTrack parseGps(const std::string& path) {
+  std::ifstream f(path);
+  if (!f) throw std::runtime_error("parseGps: 打不开 " + path);
+
+  GpsTrack track;
+  std::string line;
+  while (std::getline(f, line)) {
+    // 去掉可能的 \r（CRLF）。
+    if (!line.empty() && line.back() == '\r') line.pop_back();
+
+    std::istringstream tok(line);
+    std::vector<std::string> cols;
+    std::string c;
+    while (tok >> c) cols.push_back(c);
+    if (cols.size() < 7) continue;  // 列数不足
+
+    GpsPt p;
+    if (!parseDouble(cols[2], p.lat)) continue;  // 纬
+    if (!parseDouble(cols[4], p.lon)) continue;  // 经
+    if (!parseDouble(cols[6], p.elev)) continue;  // 高
+    track.pts.push_back(p);
+  }
+  return track;
+}
+
+XY lonLatToLocalM(double lat, double lon, double lat0, double lon0) {
+  XY xy;
+  xy.x = (lon - lon0) * kMetersPerDegLat * std::cos(lat0 * kPi / 180.0);
+  xy.y = (lat - lat0) * kMetersPerDegLat;
+  return xy;
+}
+
+PosHeading interpAlongTrack(const std::vector<XY>& trackM, double frac) {
+  PosHeading r;
+  if (trackM.empty()) return r;
+  if (trackM.size() == 1) {
+    r.pos = trackM.front();
+    return r;
+  }
+
+  // 各段长度 + 累积里程。
+  const std::size_t n = trackM.size();
+  std::vector<double> cum(n, 0.0);
+  for (std::size_t i = 1; i < n; ++i) {
+    const double dx = trackM[i].x - trackM[i - 1].x;
+    const double dy = trackM[i].y - trackM[i - 1].y;
+    cum[i] = cum[i - 1] + std::hypot(dx, dy);
+  }
+  const double total = cum.back();
+
+  // 退化（零长轨迹）：返回起点，航向取首段方向或 (1,0)。
+  if (total <= 0.0) {
+    r.pos = trackM.front();
+    return r;
+  }
+
+  if (frac <= 0.0) frac = 0.0;
+  if (frac >= 1.0) frac = 1.0;
+  const double target = frac * total;
+
+  // 找包含 target 里程的段 [i-1, i]。
+  std::size_t seg = 1;
+  while (seg < n && cum[seg] < target) ++seg;
+  if (seg >= n) seg = n - 1;
+
+  const double segLen = cum[seg] - cum[seg - 1];
+  const double localFrac = segLen > 0.0 ? (target - cum[seg - 1]) / segLen : 0.0;
+
+  const XY& a = trackM[seg - 1];
+  const XY& b = trackM[seg];
+  r.pos.x = a.x + (b.x - a.x) * localFrac;
+  r.pos.y = a.y + (b.y - a.y) * localFrac;
+
+  double dx = b.x - a.x;
+  double dy = b.y - a.y;
+  const double len = std::hypot(dx, dy);
+  if (len > 0.0) {
+    r.hx = dx / len;
+    r.hy = dy / len;
+  }
+  return r;
+}
+
+}  // namespace geopro::io::gpr
diff --git a/src/io/gpr/GpsTrack.hpp b/src/io/gpr/GpsTrack.hpp
new file mode 100644
index 0000000..5996851
--- /dev/null
+++ b/src/io/gpr/GpsTrack.hpp
@@ -0,0 +1,46 @@
+#ifndef GEOPRO_IO_GPR_GPSTRACK_HPP
+#define GEOPRO_IO_GPR_GPSTRACK_HPP
+
+#include <string>
+#include <vector>
+
+namespace geopro::io::gpr {
+
+// 一个 RTK 轨迹点（度,度,米）。
+struct GpsPt {
+  double lat = 0;   // 纬度（度）
+  double lon = 0;   // 经度（度）
+  double elev = 0;  // 高程（米）
+};
+
+// 一条测线的 RTK 轨迹。
+struct GpsTrack {
+  std::vector<GpsPt> pts;
+};
+
+// 解析 .gps 文本。每行 tab/空白分隔：
+//   日期 \t 时间 \t 纬 \t N \t 经 \t E \t 高 \t M \t 卫星
+// 取 纬(col2)/经(col4)/高(col6)。列数不足或非数字行跳过。文件打不开抛 std::runtime_error。
+GpsTrack parseGps(const std::string& path);
+
+// 局部米坐标（等距投影，绕给定原点 lat0/lon0）。
+//   x_east  = (lon-lon0)*111320*cos(lat0°)
+//   y_north = (lat-lat0)*111320
+struct XY {
+  double x = 0;  // 东向米
+  double y = 0;  // 北向米
+};
+XY lonLatToLocalM(double lat, double lon, double lat0, double lon0);
+
+// 沿轨迹按里程插值：frac∈[0,1] 返回该里程分数处的局部米坐标 + 该处航向（单位向量）。
+//   frac<=0 → 起点；frac>=1 → 终点；空/单点轨迹航向 (1,0)。
+struct PosHeading {
+  XY pos;
+  double hx = 1;  // 航向单位向量 x
+  double hy = 0;  // 航向单位向量 y
+};
+PosHeading interpAlongTrack(const std::vector<XY>& trackM, double frac);
+
+}  // namespace geopro::io::gpr
+
+#endif  // GEOPRO_IO_GPR_GPSTRACK_HPP
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index e50fdf4..66a2a60 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -62,6 +62,9 @@ target_sources(geopro_tests PRIVATE data/store/test_pyramid.cpp)
 target_sources(geopro_tests PRIVATE data/store/test_streaming_write.cpp)
 # data 层：StreamingVolumeBuilder（流式建体 B4；与非流式 buildGprVolume+write 逐 brick+meta 对拍）。
 target_sources(geopro_tests PRIVATE data/test_streaming_builder.cpp)
+# core/algo：GeoVolumeBuilder（G1 build-geo：PCA 路向旋转 + 多线统一网格重叠均值；
+# 编排 io_gpr+core+store，符号编在 geopro_store，故归此节）。
+target_sources(geopro_tests PRIVATE core/test_geo_volume_builder.cpp)
 target_link_libraries(geopro_tests PRIVATE geopro_store)
 
 # net 层：RSA 加密器。测试需直接用 OpenSSL 生成/解密密钥，故显式 find_package
@@ -207,6 +210,8 @@ target_sources(geopro_tests PRIVATE io/gpr/test_iprb_reader.cpp)
 target_sources(geopro_tests PRIVATE io/gpr/test_gpr_geometry.cpp)
 # GprSurveyAssembler：若干通道 .iprb + .ord -> GprSurvey（samples 校验/traces 对齐/Y 升序重排）。
 target_sources(geopro_tests PRIVATE io/gpr/test_gpr_survey_assembler.cpp)
+# GpsTrack：.gps 解析 + 经纬→局部米 + 沿轨迹里程插值/航向（G1 build-geo 基础，纯 C++17）。
+target_sources(geopro_tests PRIVATE io/gpr/test_gps_track.cpp)
 target_link_libraries(geopro_tests PRIVATE geopro_io_gpr)
 
 add_subdirectory(spike)   # spike S3: banded contour 渲染验证
diff --git a/tests/core/test_geo_volume_builder.cpp b/tests/core/test_geo_volume_builder.cpp
new file mode 100644
index 0000000..1c3343a
--- /dev/null
+++ b/tests/core/test_geo_volume_builder.cpp
@@ -0,0 +1,154 @@
+#include "core/algo/GeoVolumeBuilder.hpp"
+
+#include <gtest/gtest.h>
+
+#include <cmath>
+#include <cstdint>
+#include <filesystem>
+#include <fstream>
+#include <iomanip>
+#include <string>
+#include <vector>
+
+#include "data/store/ChunkedVolumeStore.hpp"
+
+namespace fs = std::filesystem;
+using namespace geopro::core;
+
+// ---- principalAxisAngle 纯函数 ----
+TEST(GeoVolumeBuilder, PcaFindsRoadDirection) {
+  // 点沿 +Y（北向）排布 → 主轴角约 ±90°(±pi/2)。
+  std::vector<double> xs, ys;
+  for (int i = 0; i < 20; ++i) {
+    xs.push_back(0.01 * i);  // 微小横向噪声
+    ys.push_back(static_cast<double>(i));
+  }
+  const double ang = principalAxisAngle(xs, ys);
+  EXPECT_NEAR(std::abs(ang), 3.14159265358979323846 / 2.0, 0.05);
+}
+
+TEST(GeoVolumeBuilder, PcaAlongEastIsZero) {
+  std::vector<double> xs, ys;
+  for (int i = 0; i < 20; ++i) {
+    xs.push_back(static_cast<double>(i));
+    ys.push_back(0.01 * i);
+  }
+  EXPECT_NEAR(principalAxisAngle(xs, ys), 0.0, 0.05);
+}
+
+TEST(GeoVolumeBuilder, PcaDegenerateReturnsZero) {
+  EXPECT_DOUBLE_EQ(principalAxisAngle({}, {}), 0.0);
+  EXPECT_DOUBLE_EQ(principalAxisAngle({1.0}, {1.0}), 0.0);
+}
+
+// ---- 合成小线建体 ----
+namespace {
+
+// 写一通道 .iprb + .iprh：值恒为 fixedVal（便于校验重叠均值）。
+void writeChannel(const fs::path& iprb, int samples, int traces,
+                  std::int16_t fixedVal) {
+  fs::path iprh = fs::path(iprb).replace_extension(".iprh");
+  std::ofstream h(iprh);
+  h << "SAMPLES: " << samples << "\n";
+  h << "LAST TRACE: " << (traces - 1) << "\n";
+  h << "CHANNELS: 2\n";
+  h << "TIMEWINDOW: 100.0\n";
+  h << "SOIL VELOCITY: 100.0\n";  // m/µs → 1e8 m/s
+  h << "DISTANCE INTERVAL: 0.05\n";
+  h.close();
+
+  std::ofstream b(iprb, std::ios::binary);
+  for (int t = 0; t < traces; ++t)
+    for (int s = 0; s < samples; ++s)
+      b.write(reinterpret_cast<const char*>(&fixedVal), sizeof(fixedVal));
+}
+
+// 写一条南北直线的 .gps（lat 从 lat0 递增到 lat1，lon 固定）。
+void writeGps(const fs::path& path, double lat0, double lat1, double lon,
+              int pts) {
+  std::ofstream f(path);
+  for (int i = 0; i < pts; ++i) {
+    const double frac = pts > 1 ? static_cast<double>(i) / (pts - 1) : 0.0;
+    const double lat = lat0 + (lat1 - lat0) * frac;
+    f << "2023-06-03\t00:00:00:000\t" << std::fixed
+      << std::setprecision(10) << lat << "\tN\t" << lon << "\tE\t9.0\tM\t4\n";
+  }
+}
+
+// 写两通道 .ord（横偏 -0.5 / +0.5，末列=1 有效）。
+void writeOrd(const fs::path& path) {
+  std::ofstream f(path);
+  f << "0 -0.500000 -1.5 1\n";
+  f << "1 0.500000 -1.5 1\n";
+}
+
+GeoLineInput makeLine(const fs::path& dir, const std::string& tag, double lat0,
+                      double lat1, double lon, int traces, std::int16_t val) {
+  const int samples = 8;
+  writeChannel(dir / (tag + "_A01.iprb"), samples, traces, val);
+  writeChannel(dir / (tag + "_A02.iprb"), samples, traces, val);
+  writeOrd(dir / (tag + ".ord"));
+  writeGps(dir / (tag + ".gps"), lat0, lat1, lon, traces);
+  GeoLineInput in;
+  in.iprb = {(dir / (tag + "_A01.iprb")).string(),
+             (dir / (tag + "_A02.iprb")).string()};
+  in.ord = (dir / (tag + ".ord")).string();
+  in.gps = (dir / (tag + ".gps")).string();
+  return in;
+}
+
+}  // namespace
+
+TEST(GeoVolumeBuilder, BuildsSyntheticLinesOverlapAveraged) {
+  const fs::path tmp = fs::temp_directory_path() / "geopro_geovol_test";
+  std::error_code ec;
+  fs::remove_all(tmp, ec);
+  fs::create_directories(tmp);
+
+  // 两条同位置南北线（lat 30.200→30.201，~111m），值不同 → 重叠 cell 取均值。
+  const double lat0 = 30.200, lat1 = 30.201, lon = 120.244;
+  std::vector<GeoLineInput> lines = {
+      makeLine(tmp, "synA_001", lat0, lat1, lon, /*traces=*/40, /*val=*/100),
+      makeLine(tmp, "synB_002", lat0, lat1, lon, /*traces=*/40, /*val=*/300),
+  };
+
+  const std::string store = (tmp / "store").string();
+  GeoGridSpec spec{/*cellXY=*/0.5, /*cellZ=*/0.1};
+  GeoBuildResult r = buildGeoVolume(lines, spec, store, /*pyramidLevels=*/1);
+
+  // 维度合理：约 111m 长 → nx 在数百量级；横路窄(~1m 阵列) → ny 小；nz>1。
+  EXPECT_GT(r.nx, 50);
+  EXPECT_GE(r.ny, 1);
+  EXPECT_GT(r.nz, 1);
+  EXPECT_GT(r.filled, 0);
+  EXPECT_LE(r.filled, r.total);
+
+  // store 可读，维度一致。
+  geopro::data::ChunkedVolumeStore s(store);
+  EXPECT_EQ(s.meta().nx, r.nx);
+  EXPECT_EQ(s.meta().ny, r.ny);
+  EXPECT_EQ(s.meta().nz, r.nz);
+  EXPECT_EQ(s.levels(), 2);  // level0 + 1
+
+  // 重叠均值：两线值 100/300，命中同 cell → 均值 200。扫所有块找非 blank 体素，
+  // 其物理值应接近 200（量化误差内）。
+  const auto& m = s.meta();
+  bool foundNonBlank = false;
+  double sampleVal = 0.0;
+  for (int bz = 0; bz < s.bricksZ() && !foundNonBlank; ++bz)
+    for (int by = 0; by < s.bricksY() && !foundNonBlank; ++by)
+      for (int bx = 0; bx < s.bricksX() && !foundNonBlank; ++bx) {
+        auto vox = s.readBrick(bx, by, bz);
+        for (std::int16_t q : vox) {
+          if (q != geopro::core::ScalarVolumeI16::kBlank) {
+            sampleVal = m.quant.toPhys(q);
+            foundNonBlank = true;
+            break;
+          }
+        }
+      }
+  ASSERT_TRUE(foundNonBlank);
+  EXPECT_NEAR(sampleVal, 200.0, 2.0);
+
+  fs::remove_all(tmp, ec);
+}
diff --git a/tests/io/gpr/test_gps_track.cpp b/tests/io/gpr/test_gps_track.cpp
new file mode 100644
index 0000000..410417d
--- /dev/null
+++ b/tests/io/gpr/test_gps_track.cpp
@@ -0,0 +1,92 @@
+#include "io/gpr/GpsTrack.hpp"
+
+#include <gtest/gtest.h>
+
+#include <cmath>
+#include <cstdio>
+#include <filesystem>
+#include <fstream>
+
+using namespace geopro::io::gpr;
+
+// 经纬→米：纬 1° ≈ 111320 m；经按 cos(lat0) 缩。
+TEST(GpsTrack, LonLatToLocalMatchesPhysics) {
+  const double lat0 = 30.204, lon0 = 120.244;
+  // 原点处归零。
+  XY o = lonLatToLocalM(lat0, lon0, lat0, lon0);
+  EXPECT_NEAR(o.x, 0.0, 1e-9);
+  EXPECT_NEAR(o.y, 0.0, 1e-9);
+
+  // 北移 0.001° 纬 → y ≈ 111.32 m，x≈0。
+  XY north = lonLatToLocalM(lat0 + 0.001, lon0, lat0, lon0);
+  EXPECT_NEAR(north.y, 111.32, 0.01);
+  EXPECT_NEAR(north.x, 0.0, 1e-6);
+
+  // 东移 0.001° 经 → x ≈ 111.32*cos(30.204°) ≈ 96.2 m。
+  XY east = lonLatToLocalM(lat0, lon0 + 0.001, lat0, lon0);
+  const double expX = 111.32 * std::cos(lat0 * 3.14159265358979323846 / 180.0);
+  EXPECT_NEAR(east.x, expX, 0.01);
+  EXPECT_NEAR(east.y, 0.0, 1e-6);
+}
+
+// 直线轨迹：frac=0/0.5/1 → 位置/航向正确。
+TEST(GpsTrack, InterpStraightLine) {
+  std::vector<XY> tr = {{0, 0}, {10, 0}, {20, 0}};  // 沿 +X 直线，长 20
+  auto p0 = interpAlongTrack(tr, 0.0);
+  EXPECT_NEAR(p0.pos.x, 0.0, 1e-9);
+  EXPECT_NEAR(p0.hx, 1.0, 1e-9);
+  EXPECT_NEAR(p0.hy, 0.0, 1e-9);
+
+  auto pm = interpAlongTrack(tr, 0.5);
+  EXPECT_NEAR(pm.pos.x, 10.0, 1e-9);
+  EXPECT_NEAR(pm.pos.y, 0.0, 1e-9);
+
+  auto p1 = interpAlongTrack(tr, 1.0);
+  EXPECT_NEAR(p1.pos.x, 20.0, 1e-9);
+  EXPECT_NEAR(p1.hx, 1.0, 1e-9);
+}
+
+// 折线（L 形）：里程一半落在拐角后，航向应是第二段方向。
+TEST(GpsTrack, InterpPolyline) {
+  std::vector<XY> tr = {{0, 0}, {10, 0}, {10, 10}};  // 先 +X 10，再 +Y 10，总长 20
+  auto pm = interpAlongTrack(tr, 0.5);  // 里程 10 = 正好拐角
+  EXPECT_NEAR(pm.pos.x, 10.0, 1e-9);
+  EXPECT_NEAR(pm.pos.y, 0.0, 1e-9);
+
+  auto p75 = interpAlongTrack(tr, 0.75);  // 里程 15 → 第二段中点 (10,5)
+  EXPECT_NEAR(p75.pos.x, 10.0, 1e-9);
+  EXPECT_NEAR(p75.pos.y, 5.0, 1e-9);
+  EXPECT_NEAR(p75.hx, 0.0, 1e-9);  // 第二段沿 +Y
+  EXPECT_NEAR(p75.hy, 1.0, 1e-9);
+}
+
+// 通道横向定位：航向 (hx,hy)，垂直 = (-hy,hx)；通道位置 = trace 位置 + o_c×垂直。
+TEST(GpsTrack, ChannelLateralPlacement) {
+  auto ph = interpAlongTrack({{0, 0}, {0, 10}}, 0.5);  // 沿 +Y，航向 (0,1)
+  EXPECT_NEAR(ph.hx, 0.0, 1e-9);
+  EXPECT_NEAR(ph.hy, 1.0, 1e-9);
+  // 垂直(航向) = (-hy, hx) = (-1, 0)。偏移 +0.5 → 通道在 (-0.5, 5)。
+  const double perpX = -ph.hy, perpY = ph.hx;
+  const double oc = 0.5;
+  const double cx = ph.pos.x + oc * perpX;
+  const double cy = ph.pos.y + oc * perpY;
+  EXPECT_NEAR(cx, -0.5, 1e-9);
+  EXPECT_NEAR(cy, 5.0, 1e-9);
+}
+
+// 解析真实格式的 .gps（tab 分隔，含 N/E/M 标记列）。
+TEST(GpsTrack, ParsesGpsFile) {
+  auto tmp = std::filesystem::temp_directory_path() / "geopro_gps_test.gps";
+  {
+    std::ofstream f(tmp);
+    f << "2023-06-03\t14:42:23:000\t30.21402519\tN\t120.24466077\tE\t9.390\tM\t4\r\n";
+    f << "2023-06-03\t14:42:23:203\t30.21402388\tN\t120.24466074\tE\t9.386\tM\t4\r\n";
+    f << "garbage line should be skipped\n";
+  }
+  GpsTrack t = parseGps(tmp.string());
+  std::filesystem::remove(tmp);
+  ASSERT_EQ(t.pts.size(), 2u);
+  EXPECT_NEAR(t.pts[0].lat, 30.21402519, 1e-8);
+  EXPECT_NEAR(t.pts[0].lon, 120.24466077, 1e-8);
+  EXPECT_NEAR(t.pts[0].elev, 9.390, 1e-6);
+}
diff --git a/tools/gpr_poc/main.cpp b/tools/gpr_poc/main.cpp
index 3c83d1e..41d9da6 100644
--- a/tools/gpr_poc/main.cpp
+++ b/tools/gpr_poc/main.cpp
@@ -26,6 +26,7 @@
 
 #include "Probe.hpp"
 
+#include "core/algo/GeoVolumeBuilder.hpp"
 #include "core/algo/GprVolumeBuilder.hpp"
 #include "core/algo/IInterpolator.hpp"
 #include "core/model/GprSurvey.hpp"
@@ -681,6 +682,117 @@ int cmdBuildStream(int argc, char** argv) {
   return 0;
 }
 
+// ============================================================================
+// build-geo：按真实 RTK 几何把多线插值进统一路向网格（Task G1）
+// ============================================================================
+//
+// 消除 build-stream 顺序拼接的退化扁带：各线 .gps RTK 轨迹 → 经纬 → 局部米 →
+// PCA 路向旋转 → 道按里程均匀分布定位、14 通道横偏垂直航向摆放 → 全部插进统一
+// 路向网格(≈4472×43×81)重叠取均值 → 量化写 ChunkedVolumeStore + 金字塔。
+int cmdBuildGeo(int argc, char** argv) {
+  const Args a = parseArgs(argc, argv, 2);
+  if (a.positional.empty()) {
+    std::cerr << "用法: gpr_poc build-geo <dir> [--cellXY 0.5] [--cellZ 0.1] "
+                 "[--out <storeDir>] [--levels 4] [--maxLines N]\n";
+    return 2;
+  }
+  const std::string dir = a.positional[0];
+  const double cellXY = std::stod(a.get("cellXY", "0.5"));
+  const double cellZ = std::stod(a.get("cellZ", "0.1"));
+  const int levels = std::stoi(a.get("levels", "4"));
+  const int maxLines = std::stoi(a.get("maxLines", "0"));
+  const std::string out =
+      a.get("out", (fs::temp_directory_path() / "gpr_store_geo").string());
+
+  std::cout << "[build-geo] dir=" << dir << " cellXY=" << cellXY
+            << " cellZ=" << cellZ << " levels=" << levels << " out=" << out
+            << "\n";
+
+  // 发现线号 → 各线 iprb/ord（复用 discoverLine）+ .gps（按线号匹配）。
+  std::vector<std::string> lineNos = discoverLines(dir);
+  if (maxLines > 0 && static_cast<int>(lineNos.size()) > maxLines)
+    lineNos.resize(maxLines);
+  std::cout << "[build-geo] 发现测线数=" << lineNos.size() << "\n";
+  if (lineNos.empty()) {
+    std::cerr << "[build-geo] 错误: 未发现任何 .ord 测线\n";
+    return 1;
+  }
+
+  std::vector<geopro::core::GeoLineInput> lines;
+  for (const std::string& ln : lineNos) {
+    const LineFiles lf = discoverLine(dir, ln);
+    if (lf.iprb.empty() || lf.ord.empty()) {
+      std::cerr << "[build-geo] 警告: 线 " << ln << " 缺 iprb/ord，跳过\n";
+      continue;
+    }
+    // .gps：匹配 "*_<ln>.gps"。
+    std::string gps;
+    for (const auto& e : fs::directory_iterator(dir)) {
+      if (!e.is_regular_file()) continue;
+      if (e.path().extension().string() != ".gps") continue;
+      const std::string stem = e.path().stem().string();
+      const std::size_t us = stem.find_last_of('_');
+      if (us != std::string::npos && stem.substr(us + 1) == ln) {
+        gps = e.path().string();
+        break;
+      }
+    }
+    if (gps.empty()) {
+      std::cerr << "[build-geo] 警告: 线 " << ln << " 缺 .gps，跳过\n";
+      continue;
+    }
+    geopro::core::GeoLineInput in;
+    in.iprb = lf.iprb;
+    in.ord = lf.ord;
+    in.gps = gps;
+    lines.push_back(std::move(in));
+  }
+  if (lines.empty()) {
+    std::cerr << "[build-geo] 错误: 无可用测线\n";
+    return 1;
+  }
+  std::cout << "[build-geo] 可用测线数=" << lines.size() << "\n";
+
+  fs::create_directories(out);
+  Stopwatch sw;
+  const geopro::core::GeoGridSpec spec{cellXY, cellZ};
+  const geopro::core::GeoBuildResult r =
+      geopro::core::buildGeoVolume(lines, spec, out, levels);
+  const double buildMs = sw.elapsedMs();
+
+  const double fillRate =
+      r.total > 0 ? static_cast<double>(r.filled) / r.total : 0.0;
+  const double rotDeg = r.rotRad * 180.0 / 3.14159265358979323846;
+  const std::int64_t dataBytes = storeDataBytes(out);
+  const double peak = Probe::peakMemMB();
+
+  std::cout << "\n=== build-geo 指标（真实 RTK 几何统一路向体）===\n";
+  std::cout << "测线数         : " << lines.size() << "\n";
+  std::cout << "体维度         : " << r.nx << " x " << r.ny << " x " << r.nz
+            << "\n";
+  std::cout << "总 cell        : " << r.total << "\n";
+  std::cout << "非空 cell      : " << r.filled << "\n";
+  std::cout << "填充率         : " << (fillRate * 100.0) << " %\n";
+  std::cout << "路向旋转角     : " << rotDeg << " ° (" << r.rotRad << " rad)\n";
+  std::cout << "网格原点(m)    : (" << r.oxM << ", " << r.oyM << ")\n";
+  std::cout << "data.bin(B)    : " << dataBytes << "  ("
+            << dataBytes / (1024.0 * 1024.0) << " MB)\n";
+  std::cout << "建体总耗时(ms) : " << buildMs << "\n";
+  std::cout << "峰值内存(MB)   : " << peak << "\n";
+
+  writeMetricLine(
+      "build-geo,lines=" + std::to_string(lines.size()) +
+      ",cellXY=" + std::to_string(cellXY) + ",cellZ=" + std::to_string(cellZ) +
+      ",nx=" + std::to_string(r.nx) + ",ny=" + std::to_string(r.ny) +
+      ",nz=" + std::to_string(r.nz) + ",total=" + std::to_string(r.total) +
+      ",filled=" + std::to_string(r.filled) +
+      ",fillRate=" + std::to_string(fillRate) +
+      ",rotDeg=" + std::to_string(rotDeg) +
+      ",buildMs=" + std::to_string(buildMs) +
+      ",peakMB=" + std::to_string(peak));
+  return 0;
+}
+
 int cmdLoad(int argc, char** argv) {
   const Args a = parseArgs(argc, argv, 2);
   if (a.positional.empty()) {
@@ -3822,6 +3934,8 @@ void usage() {
                "  gpr_poc build-stream <dir> [--cellXY 0.05] [--cellZ 0.05] "
                "[--out <storeDir>] [--levels 3] [--sliceXBricks 8] "
                "[--maxLines N]\n"
+               "  gpr_poc build-geo <dir> [--cellXY 0.5] [--cellZ 0.1] "
+               "[--out <storeDir>] [--levels 4] [--maxLines N]\n"
                "  gpr_poc load  <storeDir>\n"
                "  gpr_poc selftest\n"
                "  gpr_poc offscreen-smoke\n"
@@ -3855,6 +3969,7 @@ int main(int argc, char** argv) {
   try {
     if (cmd == "build") return cmdBuild(argc, argv);
     if (cmd == "build-stream") return cmdBuildStream(argc, argv);
+    if (cmd == "build-geo") return cmdBuildGeo(argc, argv);
     if (cmd == "load") return cmdLoad(argc, argv);
     if (cmd == "selftest") return cmdSelftest();
     if (cmd == "offscreen-smoke") return cmdOffscreenSmoke();