diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index bad9a5e..00f98a8 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -8,4 +8,5 @@
 #   add_subdirectory(view)        # QtWidgets 面板
 #   add_subdirectory(controller)  # 联动编排
 #
+add_subdirectory(core)
 add_subdirectory(app)
diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
new file mode 100644
index 0000000..64271cf
--- /dev/null
+++ b/src/core/CMakeLists.txt
@@ -0,0 +1,11 @@
+find_package(Eigen3 CONFIG REQUIRED)
+
+add_library(geopro_core STATIC
+  geo/LocalFrame.cpp
+)
+
+target_include_directories(geopro_core PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
+target_link_libraries(geopro_core PUBLIC Eigen3::Eigen)
+target_compile_features(geopro_core PUBLIC cxx_std_17)
+
+# 铁律：core 为纯业务逻辑层，绝不链接 Qt / VTK。
diff --git a/src/core/geo/LocalFrame.cpp b/src/core/geo/LocalFrame.cpp
new file mode 100644
index 0000000..28357f9
--- /dev/null
+++ b/src/core/geo/LocalFrame.cpp
@@ -0,0 +1,15 @@
+#include "geo/LocalFrame.hpp"
+namespace geopro::core {
+
+LocalFrame::LocalFrame(double originEast, double originNorth, double zDatum)
+    : originEast_(originEast), originNorth_(originNorth), zDatum_(zDatum) {}
+
+WorldPoint LocalFrame::gisToWorld(double east, double north, double elevation) const {
+    return WorldPoint{east - originEast_, north - originNorth_, elevation - zDatum_};
+}
+
+GisPoint LocalFrame::worldToGis(const WorldPoint& w) const {
+    return GisPoint{w.x + originEast_, w.y + originNorth_, w.z + zDatum_};
+}
+
+}  // namespace geopro::core
diff --git a/src/core/geo/LocalFrame.hpp b/src/core/geo/LocalFrame.hpp
new file mode 100644
index 0000000..7466656
--- /dev/null
+++ b/src/core/geo/LocalFrame.hpp
@@ -0,0 +1,21 @@
+#pragma once
+namespace geopro::core {
+
+struct WorldPoint { double x, y, z; };       // 局部米：x=East偏移, y=North偏移, z=相对Z基准
+struct GisPoint   { double east, north, elevation; };
+
+// 唯一权威「项目世界系」：双精度 GIS 原点平移到局部米，规避 VTK float 大坐标抖动。
+// 轴向钉死：world.x = Easting(projectX)，world.y = Northing(projectY)，world.z 向上为正。
+class LocalFrame {
+public:
+    LocalFrame(double originEast, double originNorth, double zDatum);
+    WorldPoint gisToWorld(double east, double north, double elevation) const;
+    GisPoint   worldToGis(const WorldPoint& w) const;
+    double originEast() const { return originEast_; }
+    double originNorth() const { return originNorth_; }
+    double zDatum() const { return zDatum_; }
+private:
+    double originEast_, originNorth_, zDatum_;
+};
+
+}  // namespace geopro::core
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 6ed3229..68bb1e5 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -9,4 +9,7 @@ target_link_libraries(geopro_tests PRIVATE GTest::gtest GTest::gtest_main)
 include(GoogleTest)
 gtest_discover_tests(geopro_tests)
 
+target_sources(geopro_tests PRIVATE core/test_local_frame.cpp)
+target_link_libraries(geopro_tests PRIVATE geopro_core)
+
 add_subdirectory(spike)   # spike S3: banded contour 渲染验证
diff --git a/tests/core/test_local_frame.cpp b/tests/core/test_local_frame.cpp
new file mode 100644
index 0000000..d772618
--- /dev/null
+++ b/tests/core/test_local_frame.cpp
@@ -0,0 +1,20 @@
+#include <gtest/gtest.h>
+#include "geo/LocalFrame.hpp"
+using geopro::core::LocalFrame;
+
+TEST(LocalFrame, GisToWorldSubtractsOriginEastNorth) {
+    LocalFrame f(/*originEast=*/516000.0, /*originNorth=*/2494000.0, /*zDatum=*/0.0);
+    auto w = f.gisToWorld(516863.6350992983, 2494259.56246985, 21.0);
+    EXPECT_NEAR(w.x, 863.6350992983, 1e-6);
+    EXPECT_NEAR(w.y, 259.56246985, 1e-6);
+    EXPECT_NEAR(w.z, 21.0, 1e-6);
+}
+
+TEST(LocalFrame, RoundTripWorldGis) {
+    LocalFrame f(516000.0, 2494000.0, 5.0);
+    auto w = f.gisToWorld(516500.0, 2494500.0, 30.0);
+    auto g = f.worldToGis(w);
+    EXPECT_NEAR(g.east, 516500.0, 1e-6);
+    EXPECT_NEAR(g.north, 2494500.0, 1e-6);
+    EXPECT_NEAR(g.elevation, 30.0, 1e-6);
+}
diff --git a/vcpkg.json b/vcpkg.json
index 3767cca..22cff44 100644
--- a/vcpkg.json
+++ b/vcpkg.json
@@ -3,6 +3,7 @@
   "version": "0.1.0",
   "description": "Geopro 3.0 desktop client (Qt6 + VTK9) - M1. 方案②-修订: Qt/VTK/ADS/QtKeychain 对接官方 MSVC Qt(不走 vcpkg); 仅非 Qt 依赖走 vcpkg, 按层递增。",
   "dependencies": [
+    "eigen3",
     "gtest",
     "nlohmann-json"
   ]