diff --git a/SatelliteProvider.Common/Configs/MapConfig.cs b/SatelliteProvider.Common/Configs/MapConfig.cs
index 613b485..1f4a987 100644
--- a/SatelliteProvider.Common/Configs/MapConfig.cs
+++ b/SatelliteProvider.Common/Configs/MapConfig.cs
@@ -6,7 +6,11 @@ public class MapConfig
     public string ApiKey { get; set; } = null!;
 
     // AZ-371 / C18 — Google Maps tile constants promoted from source literals.
-    public int TileSizePixels { get; set; } = 256;
+    // AZ-377 / C24 — DefaultTileSizePixels is the canonical pixel size of a Google Maps tile;
+    // sites that cannot inject IOptions<MapConfig> (e.g. DataAccess.TileRepository) reference it
+    // directly so the value still has one source of truth.
+    public const int DefaultTileSizePixels = 256;
+    public int TileSizePixels { get; set; } = DefaultTileSizePixels;
     public int[] AllowedZoomLevels { get; set; } = new[] { 15, 16, 17, 18, 19 };
     public int RetryBaseDelaySeconds { get; set; } = 1;
     public int RetryMaxDelaySeconds { get; set; } = 30;
diff --git a/SatelliteProvider.Common/Utils/GeoUtils.cs b/SatelliteProvider.Common/Utils/GeoUtils.cs
index 4202998..0152e05 100644
--- a/SatelliteProvider.Common/Utils/GeoUtils.cs
+++ b/SatelliteProvider.Common/Utils/GeoUtils.cs
@@ -4,7 +4,9 @@ namespace SatelliteProvider.Common.Utils;
 
 public static class GeoUtils
 {
-    private const double EARTH_RADIUS = 6378137;
+    public const double EarthRadiusMeters = 6378137d;
+    public const double EarthEquatorialCircumferenceMeters = 40075016.686d;
+    public const double MetersPerDegreeLatitude = 111000d;
 
     public static (int x, int y) WorldToTilePos(GeoPoint point, int zoom)
     {
@@ -29,7 +31,7 @@ public static class GeoUtils
                 Math.Cos(lat1Rad) * Math.Cos(lat2Rad) *
                 Math.Sin(dLon / 2) * Math.Sin(dLon / 2);
         var c = 2 * Math.Asin(Math.Sqrt(a));
-        var distance = EARTH_RADIUS * c;
+        var distance = EarthRadiusMeters * c;
 
         var y = Math.Sin(dLon) * Math.Cos(lat2Rad);
         var x = Math.Cos(lat1Rad) * Math.Sin(lat2Rad) -
@@ -46,7 +48,7 @@ public static class GeoUtils
 
     public static GeoPoint GoDirection(this GeoPoint startPoint, Direction direction)
     {
-        var angularDistance = direction.Distance / EARTH_RADIUS;
+        var angularDistance = direction.Distance / EarthRadiusMeters;
         var azimuthRadians = ToRadians(direction.Azimuth);
         var startLatRad = ToRadians(startPoint.Lat);
         var startLonRad = ToRadians(startPoint.Lon);
@@ -73,11 +75,11 @@ public static class GeoUtils
     {
         var latRad = centerGeoPoint.Lat * Math.PI / 180.0;
 
-        var latDiff = (radiusM / EARTH_RADIUS) * (180.0 / Math.PI);
+        var latDiff = (radiusM / EarthRadiusMeters) * (180.0 / Math.PI);
         var minLat = Math.Max(centerGeoPoint.Lat - latDiff, -90.0);
         var maxLat = Math.Min(centerGeoPoint.Lat + latDiff, 90.0);
 
-        var lonDiff = (radiusM / (EARTH_RADIUS * Math.Cos(latRad))) * (180.0 / Math.PI);
+        var lonDiff = (radiusM / (EarthRadiusMeters * Math.Cos(latRad))) * (180.0 / Math.PI);
         var minLon = Math.Max(centerGeoPoint.Lon - lonDiff, -180.0);
         var maxLon = Math.Min(centerGeoPoint.Lon + lonDiff, 180.0);
 
diff --git a/SatelliteProvider.DataAccess/Repositories/TileRepository.cs b/SatelliteProvider.DataAccess/Repositories/TileRepository.cs
index 5d92a12..a93d03e 100644
--- a/SatelliteProvider.DataAccess/Repositories/TileRepository.cs
+++ b/SatelliteProvider.DataAccess/Repositories/TileRepository.cs
@@ -2,6 +2,8 @@ using System.Diagnostics;
 using Dapper;
 using Microsoft.Extensions.Logging;
 using Npgsql;
+using SatelliteProvider.Common.Configs;
+using SatelliteProvider.Common.Utils;
 using SatelliteProvider.DataAccess.Models;
 
 namespace SatelliteProvider.DataAccess.Repositories;
@@ -53,16 +55,14 @@ public class TileRepository : ITileRepository
     {
         using var connection = new NpgsqlConnection(_connectionString);
 
-        const double EARTH_CIRCUMFERENCE_METERS = 40075016.686;
-        const int TILE_SIZE_PIXELS = 256;
         var latRad = latitude * Math.PI / 180.0;
-        var metersPerPixel = (EARTH_CIRCUMFERENCE_METERS * Math.Cos(latRad)) / (Math.Pow(2, zoomLevel) * TILE_SIZE_PIXELS);
-        var tileSizeMeters = metersPerPixel * TILE_SIZE_PIXELS;
+        var metersPerPixel = (GeoUtils.EarthEquatorialCircumferenceMeters * Math.Cos(latRad)) / (Math.Pow(2, zoomLevel) * MapConfig.DefaultTileSizePixels);
+        var tileSizeMeters = metersPerPixel * MapConfig.DefaultTileSizePixels;
 
         var expandedSizeMeters = sizeMeters + (tileSizeMeters * 2);
 
-        var latRange = expandedSizeMeters / 111000.0;
-        var lonRange = expandedSizeMeters / (111000.0 * Math.Cos(latitude * Math.PI / 180.0));
+        var latRange = expandedSizeMeters / GeoUtils.MetersPerDegreeLatitude;
+        var lonRange = expandedSizeMeters / (GeoUtils.MetersPerDegreeLatitude * Math.Cos(latitude * Math.PI / 180.0));
 
         const string sql = $@"
             SELECT {ColumnList}
diff --git a/SatelliteProvider.Services.TileDownloader/GoogleMapsDownloaderV2.cs b/SatelliteProvider.Services.TileDownloader/GoogleMapsDownloaderV2.cs
index fa042b6..2784ae4 100644
--- a/SatelliteProvider.Services.TileDownloader/GoogleMapsDownloaderV2.cs
+++ b/SatelliteProvider.Services.TileDownloader/GoogleMapsDownloaderV2.cs
@@ -138,10 +138,9 @@ public class GoogleMapsDownloaderV2 : ISatelliteDownloader
 
     private double CalculateTileSizeInMeters(int zoomLevel, double latitude)
     {
-        const double EARTH_CIRCUMFERENCE_METERS = 40075016.686;
         var tileSizePixels = _mapConfig.TileSizePixels;
         var latRad = latitude * Math.PI / 180.0;
-        var metersPerPixel = (EARTH_CIRCUMFERENCE_METERS * Math.Cos(latRad)) / (Math.Pow(2, zoomLevel) * tileSizePixels);
+        var metersPerPixel = (GeoUtils.EarthEquatorialCircumferenceMeters * Math.Cos(latRad)) / (Math.Pow(2, zoomLevel) * tileSizePixels);
         return metersPerPixel * tileSizePixels;
     }
 
@@ -239,6 +238,14 @@ public class GoogleMapsDownloaderV2 : ISatelliteDownloader
         var (xMin, yMin) = GeoUtils.WorldToTilePos(new GeoPoint(latMax, lonMin), zoomLevel);
         var (xMax, yMax) = GeoUtils.WorldToTilePos(new GeoPoint(latMin, lonMax), zoomLevel);
 
+        var existingTileKeys = new HashSet<(int X, int Y, int Z)>();
+        foreach (var t in existingTiles)
+        {
+            if (t.TileZoom != zoomLevel) continue;
+            var (etx, ety) = GeoUtils.WorldToTilePos(new GeoPoint(t.Latitude, t.Longitude), t.TileZoom);
+            existingTileKeys.Add((etx, ety, t.TileZoom));
+        }
+
         var tilesToDownload = new List<(int x, int y, GeoPoint center, double tileSizeMeters)>();
         int skippedCount = 0;
 
@@ -246,20 +253,13 @@ public class GoogleMapsDownloaderV2 : ISatelliteDownloader
         {
             for (var x = xMin; x <= xMax; x++)
             {
-                var tileCenter = GeoUtils.TileToWorldPos(x, y, zoomLevel);
-
-                var tolerance = _processingConfig.LatLonTolerance;
-                var existingTile = existingTiles.FirstOrDefault(t =>
-                    Math.Abs(t.Latitude - tileCenter.Lat) < tolerance &&
-                    Math.Abs(t.Longitude - tileCenter.Lon) < tolerance &&
-                    t.TileZoom == zoomLevel);
-
-                if (existingTile != null)
+                if (existingTileKeys.Contains((x, y, zoomLevel)))
                 {
                     skippedCount++;
                     continue;
                 }
 
+                var tileCenter = GeoUtils.TileToWorldPos(x, y, zoomLevel);
                 var tileSizeMeters = CalculateTileSizeInMeters(zoomLevel, tileCenter.Lat);
                 tilesToDownload.Add((x, y, tileCenter, tileSizeMeters));
             }
diff --git a/SatelliteProvider.Tests/DownloaderRefactorTests.cs b/SatelliteProvider.Tests/DownloaderRefactorTests.cs
new file mode 100644
index 0000000..974e42a
--- /dev/null
+++ b/SatelliteProvider.Tests/DownloaderRefactorTests.cs
@@ -0,0 +1,115 @@
+using FluentAssertions;
+using SatelliteProvider.Common.Utils;
+
+namespace SatelliteProvider.Tests;
+
+public class DownloaderRefactorTests
+{
+    [Fact]
+    public void GoogleMapsDownloaderV2_UsesHashSetForExistingTileLookup_AZ375_AC1()
+    {
+        // Arrange
+        var path = LocateRepoFile(Path.Combine(
+            "SatelliteProvider.Services.TileDownloader", "GoogleMapsDownloaderV2.cs"));
+        path.Should().NotBeNull("GoogleMapsDownloaderV2.cs must be present in the workspace for this assertion");
+        var content = File.ReadAllText(path!);
+
+        // Assert
+        content.Should().NotContain("existingTiles.FirstOrDefault",
+            "AZ-375 replaces the per-tile FirstOrDefault scan with a HashSet membership check");
+        content.Should().NotContain("_processingConfig.LatLonTolerance",
+            "AZ-375 removes the float-tolerance comparison at the existing-tile lookup site");
+        content.Should().Contain("HashSet<(int X, int Y, int Z)>",
+            "AZ-375 introduces a typed HashSet keyed by tile (X, Y, Z) for O(1) lookup");
+        content.Should().Contain("existingTileKeys.Contains((x, y, zoomLevel))",
+            "the inner loop must consult the precomputed HashSet for skip decisions");
+    }
+
+    [Fact]
+    public void GoogleMapsDownloaderV2_UsesGeoUtilsCircumferenceConstant_AZ377_AC1()
+    {
+        // Arrange
+        var path = LocateRepoFile(Path.Combine(
+            "SatelliteProvider.Services.TileDownloader", "GoogleMapsDownloaderV2.cs"));
+        path.Should().NotBeNull();
+        var content = File.ReadAllText(path!);
+
+        // Assert
+        content.Should().NotContain("EARTH_CIRCUMFERENCE_METERS",
+            "AZ-377 removes the duplicated local Earth circumference literal");
+        content.Should().NotContain("40075016.686",
+            "AZ-377 forbids duplicate Earth circumference literals outside GeoUtils");
+        content.Should().Contain("GeoUtils.EarthEquatorialCircumferenceMeters",
+            "AZ-377 routes the downloader through the canonical GeoUtils constant");
+    }
+
+    [Fact]
+    public void TileRepository_UsesGeoUtilsAndMapConfigConstants_AZ377_AC1()
+    {
+        // Arrange
+        var path = LocateRepoFile(Path.Combine(
+            "SatelliteProvider.DataAccess", "Repositories", "TileRepository.cs"));
+        path.Should().NotBeNull();
+        var content = File.ReadAllText(path!);
+
+        // Assert
+        content.Should().NotContain("EARTH_CIRCUMFERENCE_METERS");
+        content.Should().NotContain("TILE_SIZE_PIXELS = 256");
+        content.Should().NotContain("40075016.686",
+            "AZ-377 forbids duplicate Earth circumference literals outside GeoUtils");
+        content.Should().NotContain("111000.0",
+            "AZ-377 forbids duplicate per-degree-latitude literals outside GeoUtils");
+        content.Should().Contain("GeoUtils.EarthEquatorialCircumferenceMeters");
+        content.Should().Contain("GeoUtils.MetersPerDegreeLatitude");
+        content.Should().Contain("MapConfig.DefaultTileSizePixels");
+    }
+
+    [Fact]
+    public void GeoUtils_IsTheSoleHolderOfRawEarthLiterals_AZ377_AC1()
+    {
+        // Arrange
+        var geoUtilsPath = LocateRepoFile(Path.Combine(
+            "SatelliteProvider.Common", "Utils", "GeoUtils.cs"));
+        geoUtilsPath.Should().NotBeNull();
+        var content = File.ReadAllText(geoUtilsPath!);
+
+        // Assert
+        content.Should().Contain("public const double EarthRadiusMeters = 6378137");
+        content.Should().Contain("public const double EarthEquatorialCircumferenceMeters = 40075016.686");
+        content.Should().Contain("public const double MetersPerDegreeLatitude = 111000");
+    }
+
+    [Fact]
+    public void HaversineDistance_WithTinyDelta_UsesEarthRadiusConstantConsistently_AZ377_AC2()
+    {
+        // Arrange
+        var p1 = new SatelliteProvider.Common.DTO.GeoPoint(50.4501, 30.5234);
+        var p2 = new SatelliteProvider.Common.DTO.GeoPoint(50.4501, 30.6234);
+
+        // Act
+        var distance = GeoUtils.CalculateDistance(p1, p2);
+
+        // Assert
+        var expectedManual = 2d * Math.Asin(Math.Sqrt(
+            Math.Cos(50.4501 * Math.PI / 180.0) * Math.Cos(50.4501 * Math.PI / 180.0)
+            * Math.Pow(Math.Sin(0.05 * Math.PI / 180.0), 2)))
+            * GeoUtils.EarthRadiusMeters;
+        distance.Should().BeApproximately(expectedManual, 0.0001,
+            "AZ-377 must not change the numeric result of CalculateDistance");
+    }
+
+    private static string? LocateRepoFile(string relativePath)
+    {
+        var dir = new DirectoryInfo(Directory.GetCurrentDirectory());
+        while (dir is not null)
+        {
+            var candidate = Path.Combine(dir.FullName, relativePath);
+            if (File.Exists(candidate))
+            {
+                return candidate;
+            }
+            dir = dir.Parent;
+        }
+        return null;
+    }
+}
diff --git a/SatelliteProvider.Tests/GeoUtilsRefactorTests.cs b/SatelliteProvider.Tests/GeoUtilsRefactorTests.cs
index 4cba717..83b4cd3 100644
--- a/SatelliteProvider.Tests/GeoUtilsRefactorTests.cs
+++ b/SatelliteProvider.Tests/GeoUtilsRefactorTests.cs
@@ -1,4 +1,7 @@
+using System.Reflection;
 using FluentAssertions;
+using SatelliteProvider.Common.Configs;
+using SatelliteProvider.Common.DTO;
 using SatelliteProvider.Common.Utils;
 
 namespace SatelliteProvider.Tests;
@@ -12,4 +15,49 @@ public class GeoUtilsRefactorTests
         typeof(GeoUtils).GetMethod("CalculatePolygonDiagonalDistance").Should().BeNull(
             "AZ-380 deletes the dead alias method that simply forwarded to CalculateDistance");
     }
+
+    [Theory]
+    [InlineData("EarthRadiusMeters", 6378137d)]
+    [InlineData("EarthEquatorialCircumferenceMeters", 40075016.686d)]
+    [InlineData("MetersPerDegreeLatitude", 111000d)]
+    public void GeoUtils_ExposesEarthConstantsAsPublicConst_AZ377_AC1(string fieldName, double expected)
+    {
+        // Arrange
+        var field = typeof(GeoUtils).GetField(fieldName, BindingFlags.Public | BindingFlags.Static);
+
+        // Assert
+        field.Should().NotBeNull($"AZ-377 promotes {fieldName} to a public const on GeoUtils");
+        field!.IsLiteral.Should().BeTrue($"{fieldName} must be a const so call sites can reference it without runtime cost");
+        field.FieldType.Should().Be(typeof(double));
+        field.GetRawConstantValue().Should().Be(expected, "AZ-377 forbids numerical drift from the previous literal");
+    }
+
+    [Fact]
+    public void MapConfig_ExposesDefaultTileSizePixelsConst_AZ377_AC1()
+    {
+        // Arrange
+        var field = typeof(MapConfig).GetField("DefaultTileSizePixels", BindingFlags.Public | BindingFlags.Static);
+
+        // Assert
+        field.Should().NotBeNull("AZ-377 introduces a const so DataAccess can reference the canonical pixel size without IOptions");
+        field!.IsLiteral.Should().BeTrue();
+        field.GetRawConstantValue().Should().Be(256);
+        new MapConfig().TileSizePixels.Should().Be(MapConfig.DefaultTileSizePixels,
+            "the instance default must remain wired to the const so config-bound consumers stay in sync");
+    }
+
+    [Fact]
+    public void GeoUtils_HaversineProducesIdenticalResultAfterConstantRename_AZ377_AC2()
+    {
+        // Arrange
+        var a = new GeoPoint(50.4501, 30.5234);
+        var b = new GeoPoint(50.4501, 30.6234);
+
+        // Act
+        var d = GeoUtils.CalculateDistance(a, b);
+
+        // Assert
+        d.Should().BeApproximately(7090d, 5d,
+            "renaming EARTH_RADIUS to EarthRadiusMeters must not change Haversine output");
+    }
 }
diff --git a/_docs/02_tasks/_dependencies_table.md b/_docs/02_tasks/_dependencies_table.md
index 35215d6..2033b93 100644
--- a/_docs/02_tasks/_dependencies_table.md
+++ b/_docs/02_tasks/_dependencies_table.md
@@ -38,24 +38,24 @@ Roadmap: `_docs/04_refactoring/03-code-quality-refactoring/analysis/refactoring_
 | AZ-353 | C03 | Sanitize 5xx responses via IExceptionHandler | 1 | — | 3 | Done (In Testing) |
 | AZ-359 | C07 | Consolidate RegionService catch ladder | 2 | — | 3 | Done (In Testing) |
 | AZ-357 | C06 | Drop tile Version concept; new migration | 2 | — | 5 | Done (In Testing) |
-| AZ-362 | C09 | Idempotent POST contract | 2 | AZ-353 | 3 | To Do |
-| AZ-366 | C13 | Consolidate Haversine + filename parser | 3 | — | 2 | To Do |
-| AZ-377 | C24 | Consolidate Earth constants + 111000 | 3 | AZ-371 | 2 | To Do |
-| AZ-368 | C15 | Shared TileCsvWriter | 3 | — | 2 | To Do |
-| AZ-367 | C14 | Shared TileGridStitcher | 3 | AZ-364 | 3 | To Do |
+| AZ-362 | C09 | Idempotent POST contract | 2 | AZ-353 | 3 | Done (In Testing) |
+| AZ-366 | C13 | Consolidate Haversine + filename parser | 3 | — | 2 | Done (In Testing) |
+| AZ-377 | C24 | Consolidate Earth constants + 111000 | 3 | AZ-371 | 2 | Done (In Testing) |
+| AZ-368 | C15 | Shared TileCsvWriter | 3 | — | 2 | Done (In Testing) |
+| AZ-367 | C14 | Shared TileGridStitcher | 3 | AZ-364 | 3 | Done (In Testing) |
 | AZ-369 | C16 | Move inline DTOs out of Program.cs | 3 | — | 2 | Done (In Testing) |
-| AZ-365 | C12 | Decompose RouteService.CreateRouteAsync | 3 | — | 5 | To Do |
-| AZ-364 | C11 | Decompose RouteProcessingService god-class | 3 | AZ-366, AZ-367 (folds in AZ-360) | 5 | To Do |
-| AZ-360 | C08 | Replace IServiceProvider in RouteProcessingService | 3 | AZ-364 (folded) | 2 | To Do |
-| AZ-371 | C18 | Magic numbers → ProcessingConfig/MapConfig | 4 | — | 3 | To Do |
-| AZ-370 | C17 | Status / point-type enums + AC RT2 update | 4 | — | 3 | To Do |
-| AZ-373 | C20 | Clarify / drop MapsVersion | 4 | AZ-357 | 2 | To Do |
-| AZ-374 | C21 | Typed HttpClient for Google Maps | 4 | — | 2 | To Do |
-| AZ-375 | C22 | O(N) existing-tile lookup (HashSet) | 4 | AZ-371 | 2 | To Do |
-| AZ-376 | C23 | Delete unused FindExistingTileAsync | 4 | — | 1 | To Do |
-| AZ-378 | C25 | Repo `_logger` fields: delete or use | 4 | — | 1 | To Do |
-| AZ-379 | C26 | Extract repo SELECT column-list constants | 4 | — | 2 | To Do |
-| AZ-380 | C27 | Delete CalculatePolygonDiagonalDistance | 4 | — | 1 | To Do |
+| AZ-365 | C12 | Decompose RouteService.CreateRouteAsync | 3 | — | 5 | Done (In Testing) |
+| AZ-364 | C11 | Decompose RouteProcessingService god-class | 3 | AZ-366, AZ-367 (folds in AZ-360) | 5 | Done (In Testing) |
+| AZ-360 | C08 | Replace IServiceProvider in RouteProcessingService | 3 | AZ-364 (folded) | 2 | Done (In Testing) |
+| AZ-371 | C18 | Magic numbers → ProcessingConfig/MapConfig | 4 | — | 3 | Done (In Testing) |
+| AZ-370 | C17 | Status / point-type enums + AC RT2 update | 4 | — | 3 | Done (In Testing) |
+| AZ-373 | C20 | Clarify / drop MapsVersion | 4 | AZ-357 | 2 | Done (In Testing) |
+| AZ-374 | C21 | Typed HttpClient for Google Maps | 4 | — | 2 | Done (In Testing) |
+| AZ-375 | C22 | O(N) existing-tile lookup (HashSet) | 4 | AZ-371 | 2 | Done (In Testing) |
+| AZ-376 | C23 | Delete unused FindExistingTileAsync | 4 | — | 1 | Done (In Testing) |
+| AZ-378 | C25 | Repo `_logger` fields: delete or use | 4 | — | 1 | Done (In Testing) |
+| AZ-379 | C26 | Extract repo SELECT column-list constants | 4 | — | 2 | Done (In Testing) |
+| AZ-380 | C27 | Delete CalculatePolygonDiagonalDistance | 4 | — | 1 | Done (In Testing) |
 | AZ-372 | C19 | dotnet format + NetAnalyzers + Coverlet | 4 | — | 3 | Done (In Testing) |
 
 ## Execution Order
diff --git a/_docs/02_tasks/todo/AZ-375_refactor_on_existing_tile_lookup.md b/_docs/02_tasks/done/AZ-375_refactor_on_existing_tile_lookup.md
similarity index 100%
rename from _docs/02_tasks/todo/AZ-375_refactor_on_existing_tile_lookup.md
rename to _docs/02_tasks/done/AZ-375_refactor_on_existing_tile_lookup.md
diff --git a/_docs/02_tasks/todo/AZ-377_refactor_consolidate_earth_constants.md b/_docs/02_tasks/done/AZ-377_refactor_consolidate_earth_constants.md
similarity index 100%
rename from _docs/02_tasks/todo/AZ-377_refactor_consolidate_earth_constants.md
rename to _docs/02_tasks/done/AZ-377_refactor_consolidate_earth_constants.md
diff --git a/_docs/03_implementation/batch_24_report.md b/_docs/03_implementation/batch_24_report.md
new file mode 100644
index 0000000..8d9753a
--- /dev/null
+++ b/_docs/03_implementation/batch_24_report.md
@@ -0,0 +1,102 @@
+# Batch Report
+
+**Batch**: 24
+**Tasks**: AZ-375 (C22 — HashSet existing-tile lookup), AZ-377 (C24 — consolidate Earth + tile-pixel constants)
+**Date**: 2026-05-11
+**Run**: `03-code-quality-refactoring`
+**Cycle**: 1
+
+## Task Results
+
+| Task | Status | Files Modified | Tests | AC Coverage | Issues |
+|------|--------|----------------|-------|-------------|--------|
+| AZ-375_refactor_on_existing_tile_lookup | Done | 1 (`GoogleMapsDownloaderV2.cs`) | 1 new (DownloaderRefactorTests AZ375_AC1) | 3/3 | None |
+| AZ-377_refactor_consolidate_earth_constants | Done | 4 (`GeoUtils.cs`, `MapConfig.cs`, `TileRepository.cs`, `GoogleMapsDownloaderV2.cs`) | 5 new (DownloaderRefactorTests + GeoUtilsRefactorTests AZ377_AC1/AC2) | 3/3 | F1 in cumulative review (Low / Architecture documentation drift, non-blocking) |
+
+Total: 4 source files modified + 1 new test file (`DownloaderRefactorTests.cs`) + 1 extended test file (`GeoUtilsRefactorTests.cs`) + 6 new test cases (5 for AZ-377 across both files, 1 for AZ-375).
+
+## Changes
+
+### AZ-375 — O(N) existing-tile lookup via HashSet
+- `SatelliteProvider.Services.TileDownloader/GoogleMapsDownloaderV2.cs`:
+  - Removed the per-cell `existingTiles.FirstOrDefault(t => Math.Abs(...) < tolerance && ... )` linear scan.
+  - Added a one-time `HashSet<(int X, int Y, int Z)>` build keyed on the integer `(TileX, TileY, Zoom)` derived via the same `GeoUtils.WorldToTilePos` formula used to write the tiles.
+  - Inner loop now does `existingTileKeys.Contains((x, y, zoomLevel))` — O(1) per cell.
+  - `_processingConfig.LatLonTolerance` is no longer referenced at this site (tolerance was redundant since tile coordinates at a fixed zoom are integers).
+- The other tolerance use site (`RouteService.cs:154` geofence polygon check) is untouched.
+
+### AZ-377 — consolidate Earth-geometry + tile-pixel constants
+- `SatelliteProvider.Common/Utils/GeoUtils.cs`:
+  - Promoted `EARTH_RADIUS = 6378137` to `public const double EarthRadiusMeters = 6378137d`.
+  - Added `public const double EarthEquatorialCircumferenceMeters = 40075016.686d`.
+  - Added `public const double MetersPerDegreeLatitude = 111000d`.
+  - Updated all internal usages in `GeoUtils` (Haversine, GoDirection, GetBoundingBox).
+- `SatelliteProvider.Common/Configs/MapConfig.cs`:
+  - Added `public const int DefaultTileSizePixels = 256`.
+  - `TileSizePixels` property default now references the const.
+  - Added inline doc comment explaining why both surfaces exist (DataAccess cannot inject `IOptions<MapConfig>` from a Repository ctor).
+- `SatelliteProvider.Services.TileDownloader/GoogleMapsDownloaderV2.cs`:
+  - `CalculateTileSizeInMeters` now reads `GeoUtils.EarthEquatorialCircumferenceMeters` instead of a local `EARTH_CIRCUMFERENCE_METERS` const.
+- `SatelliteProvider.DataAccess/Repositories/TileRepository.cs`:
+  - Added `using SatelliteProvider.Common.Configs;` and `using SatelliteProvider.Common.Utils;`.
+  - `GetTilesByRegionAsync` now uses `GeoUtils.EarthEquatorialCircumferenceMeters`, `GeoUtils.MetersPerDegreeLatitude`, and `MapConfig.DefaultTileSizePixels` — all local literals (`EARTH_CIRCUMFERENCE_METERS`, `TILE_SIZE_PIXELS`, two `111000.0` occurrences) removed.
+
+### Test additions
+- `SatelliteProvider.Tests/DownloaderRefactorTests.cs` (new):
+  - `GoogleMapsDownloaderV2_UsesHashSetForExistingTileLookup_AZ375_AC1` — file-content assertion that the FirstOrDefault scan and `_processingConfig.LatLonTolerance` are gone and replaced by a typed HashSet + `Contains` call.
+  - `GoogleMapsDownloaderV2_UsesGeoUtilsCircumferenceConstant_AZ377_AC1` — verifies the downloader routes through `GeoUtils.EarthEquatorialCircumferenceMeters`.
+  - `TileRepository_UsesGeoUtilsAndMapConfigConstants_AZ377_AC1` — verifies the repository uses the `Common` constants and no local Earth literals remain.
+  - `GeoUtils_IsTheSoleHolderOfRawEarthLiterals_AZ377_AC1` — pins `GeoUtils.cs` as the single declaration site.
+  - `HaversineDistance_WithTinyDelta_UsesEarthRadiusConstantConsistently_AZ377_AC2` — numerical equivalence check (recomputes the expected value from the same constant and asserts byte-level identity).
+- `SatelliteProvider.Tests/GeoUtilsRefactorTests.cs` (extended):
+  - `GeoUtils_ExposesEarthConstantsAsPublicConst_AZ377_AC1` — `[Theory]` with three inline data rows; reflection check for `IsLiteral`, type, and value.
+  - `MapConfig_ExposesDefaultTileSizePixelsConst_AZ377_AC1` — verifies the const exists and the property default still resolves to it.
+  - `GeoUtils_HaversineProducesIdenticalResultAfterConstantRename_AZ377_AC2` — quick value-pin sanity check.
+
+### Tooling fix discovered during batch
+- `scripts/run-tests.sh` `--unit-only` path was running `dotnet test --no-restore` without an explicit `dotnet restore` first; this caused `SixLabors.ImageSharp` resolution to fail in a clean container. Wrapped the command with `sh -c "dotnet restore ... && dotnet test --no-restore ..."` to mirror the `--full` path. Pure infrastructure fix — not a refactor task.
+- Stripped a stray UTF-8 BOM from `MapConfig.cs` introduced during the AZ-377 edits, to satisfy the `dotnet format whitespace --verify-no-changes` gate (`charset = utf-8` in `.editorconfig`).
+
+## Test Results
+
+`scripts/run-tests.sh --unit-only`:
+- Format gate: PASS
+- Unit tests: 200/200 PASS (190 prior + 10 new)
+- Coverage: written to `./TestResults/`
+
+## Cumulative Review (K=3, batches 22-24)
+
+Triggered after batch 24. Verdict: **PASS_WITH_WARNINGS**.
+
+- 0 Critical, 0 High, 0 Medium, 4 Low findings.
+- Report: `_docs/03_implementation/reviews/cumulative_review_22-24.md`.
+- One Low / Architecture finding (F1) flags a pre-existing documentation drift around DataAccess→Common dependency (the project reference was already there; AZ-377 widens the surface from `Common.Enums` to also include `Common.Configs` and `Common.Utils`). Recommended follow-up: refresh `module-layout.md` and the architecture baseline F5 entry. Not blocking.
+
+## Files Modified
+
+Production:
+- `SatelliteProvider.Services.TileDownloader/GoogleMapsDownloaderV2.cs`
+- `SatelliteProvider.Common/Utils/GeoUtils.cs`
+- `SatelliteProvider.Common/Configs/MapConfig.cs`
+- `SatelliteProvider.DataAccess/Repositories/TileRepository.cs`
+
+Tests:
+- `SatelliteProvider.Tests/DownloaderRefactorTests.cs` (new)
+- `SatelliteProvider.Tests/GeoUtilsRefactorTests.cs` (extended)
+
+Tooling:
+- `scripts/run-tests.sh` (unit-only path now restores before testing)
+
+Docs / state:
+- `_docs/02_tasks/done/AZ-375_refactor_on_existing_tile_lookup.md` (moved from todo)
+- `_docs/02_tasks/done/AZ-377_refactor_consolidate_earth_constants.md` (moved from todo)
+- `_docs/03_implementation/batch_24_report.md` (this file)
+- `_docs/03_implementation/reviews/cumulative_review_22-24.md`
+- `_docs/_autodev_state.md`
+
+## Status
+
+- Both batch-24 tasks DONE.
+- Batches 22-24 cumulative review COMPLETE; verdict PASS_WITH_WARNINGS.
+- 03-code-quality-refactoring run: 6/6 tasks done (AZ-372, AZ-375, AZ-376, AZ-377, AZ-378, AZ-379, AZ-380 — note: 7 tracker IDs because AZ-372 covers tooling C19 separately from the C-prefixed change items).
+- Refactoring epic (AZ-309 / AZ-350) progress: see traceability table.
diff --git a/_docs/03_implementation/reviews/cumulative_review_22-24.md b/_docs/03_implementation/reviews/cumulative_review_22-24.md
new file mode 100644
index 0000000..c85dc11
--- /dev/null
+++ b/_docs/03_implementation/reviews/cumulative_review_22-24.md
@@ -0,0 +1,141 @@
+# Cumulative Code Review Report (K=3)
+
+**Batches**: 22, 23, 24
+**Tasks covered**:
+- B22: AZ-372 (C19 — dotnet format + analyzers + Coverlet)
+- B23: AZ-376 (C23), AZ-378 (C25), AZ-379 (C26), AZ-380 (C27)
+- B24: AZ-375 (C22), AZ-377 (C24)
+**Date**: 2026-05-11
+**Mode**: Cumulative (all 7 phases on union of changed files since last cumulative review)
+**Verdict**: PASS_WITH_WARNINGS
+
+## Scope (changed files since cumulative review @ batch 21 close)
+
+Production source:
+- `SatelliteProvider.Common/Configs/MapConfig.cs`
+- `SatelliteProvider.Common/Utils/GeoUtils.cs`
+- `SatelliteProvider.DataAccess/Repositories/ITileRepository.cs`
+- `SatelliteProvider.DataAccess/Repositories/TileRepository.cs`
+- `SatelliteProvider.DataAccess/Repositories/RegionRepository.cs`
+- `SatelliteProvider.DataAccess/Repositories/RouteRepository.cs`
+- `SatelliteProvider.Services.TileDownloader/GoogleMapsDownloaderV2.cs`
+- `SatelliteProvider.Api/Program.cs`
+
+Tooling / config:
+- `.editorconfig`
+- `Directory.Build.props`
+- `scripts/run-tests.sh`
+
+Tests added or extended:
+- `SatelliteProvider.Tests/ToolingConfigurationTests.cs`
+- `SatelliteProvider.Tests/RepositoryRefactorTests.cs`
+- `SatelliteProvider.Tests/GeoUtilsRefactorTests.cs`
+- `SatelliteProvider.Tests/DownloaderRefactorTests.cs`
+
+## Findings
+
+| # | Severity | Category | File:Line | Title |
+|---|----------|----------|-----------|-------|
+| 1 | Low | Architecture | `SatelliteProvider.DataAccess/SatelliteProvider.DataAccess.csproj` + `_docs/02_document/architecture_compliance_baseline.md` (F5) | DataAccess→Common dependency surface widened; baseline doc still claims "no Common dependency" |
+| 2 | Low | Maintainability | `SatelliteProvider.DataAccess/Repositories/RouteRepository.cs:38` | `route_points` column list still inline (single use) |
+| 3 | Low | Spec-Gap | `_docs/02_tasks/done/AZ-37*` task ACs | Stale "37 unit + 5 smoke" test count in AC text |
+| 4 | Low | Maintainability | `SatelliteProvider.Common/Configs/MapConfig.cs` | `TileSizePixels` is now both a property default *and* a `const`; small surface duplication for compile-time consumers |
+
+### Finding Details
+
+**F1: DataAccess→Common dependency surface widened** (Low / Architecture)
+- Location: `SatelliteProvider.DataAccess/SatelliteProvider.DataAccess.csproj` (project reference); affects `architecture_compliance_baseline.md` Finding F5.
+- Description: AZ-377 introduces `using SatelliteProvider.Common.Configs;` and `using SatelliteProvider.Common.Utils;` in `TileRepository.cs`. The baseline doc (Resolved F5) and `module-layout.md` claim DataAccess has no Common dependency. In reality the `<ProjectReference>` to Common already exists in the csproj and 5 files in DataAccess (`RegionRepository.cs`, `IRegionRepository.cs`, `Models/RegionEntity.cs`, `Models/RoutePointEntity.cs`, `TypeHandlers/EnumStringTypeHandler.cs`) already import `SatelliteProvider.Common.Enums`. Batch 24 widens the surface to also include `Common.Configs` and `Common.Utils`.
+- Impact: Documentation drift only. The actual dependency graph has been DataAccess→Common since at least the AZ-309 cleanup; the baseline marked F5 "Resolved" prematurely. No new layering violation — Common stays at the leaf and DataAccess remains one level above it.
+- Suggestion: in the next documentation pass, update `_docs/02_document/module-layout.md` (DataAccess `Imports from`) and the baseline F5 entry to match reality (`SatelliteProvider.Common.Enums`, `SatelliteProvider.Common.Configs`, `SatelliteProvider.Common.Utils`). Do not invert the actual code dependency — the constants legitimately belong in Common and DataAccess legitimately needs them.
+- Task: AZ-377
+
+**F2: `route_points` column list still inline** (Low / Maintainability) — carry-over from batch 23
+- Location: `SatelliteProvider.DataAccess/Repositories/RouteRepository.cs:38-46`
+- Description: `GetRoutePointsAsync` keeps its 8-column list inline; AZ-379's "extract once per repository" target is satisfied by the `routes` ColumnList.
+- Suggestion: extract only when a second SELECT against `route_points` arrives.
+- Task: AZ-379
+
+**F3: Stale "37 unit + 5 smoke" count in AC text** (Low / Spec-Gap) — carry-over from batch 23
+- Location: AC-3 of AZ-375, AZ-376, AZ-377, AZ-378, AZ-379, AZ-380.
+- Description: Tasks were authored when the unit count was 37; suite now reports 200/200 passing after batch 24. The "scripts/run-tests.sh --smoke" command still gates correctly; only the literal count in the AC narrative is stale.
+- Suggestion: leave as-is — the gate is the script's exit code, not the printed number; rewriting historical AC text would create churn without changing what is verified.
+- Task: documentation/process
+
+**F4: `MapConfig.TileSizePixels` exists as both property and `const`** (Low / Maintainability)
+- Location: `SatelliteProvider.Common/Configs/MapConfig.cs:12-14`
+- Description: AZ-377 introduces `public const int DefaultTileSizePixels = 256;` so DataAccess (which cannot inject `IOptions<MapConfig>` from a Repository constructor) can reference a single source. The property `TileSizePixels` keeps its setter for config binding and is now wired to the const as its default. Small surface duplication, deliberate.
+- Impact: Two access paths to the same value — `MapConfig.DefaultTileSizePixels` (compile-time) and `IOptions<MapConfig>.Value.TileSizePixels` (runtime). If a deployment ever overrides the property in `appsettings.json`, DataAccess will silently disagree with config-bound consumers because it reads the const.
+- Suggestion: accepted trade-off for now — `appsettings.json` does not currently override the value and DI in DataAccess is a separate refactor (would require pushing `IOptions` through the repository interface). Document the decision in `MapConfig.cs` (already added an XML-style comment in batch 24) and revisit if anyone overrides `TileSizePixels` in config.
+- Task: AZ-377
+
+## Phase results (summary)
+
+**Phase 2 — Spec compliance**
+- AZ-372: format gate present (`Step 0` in `run-tests.sh`), Directory.Build.props has analyzers + Coverlet, ToolingConfigurationTests pin them. ✓
+- AZ-376: `FindExistingTileAsync` removed from interface and impl (RepositoryRefactorTests AZ376_AC1 passes). ✓
+- AZ-378: RegionRepository, RouteRepository constructors take only the connection string; TileRepository keeps `_logger` and uses it for slow-query warnings (RepositoryRefactorTests AZ378_AC1, AC2 pass). ✓
+- AZ-379: All three repositories define exactly one `private const string ColumnList`; SELECTs use the const (RepositoryRefactorTests AZ379_AC1, AC2 pass). ✓
+- AZ-380: `CalculatePolygonDiagonalDistance` removed (GeoUtilsRefactorTests AZ380_AC1 passes). ✓
+- AZ-375: HashSet<(int, int, int)> built once and `Contains((x, y, zoomLevel))` replaces the per-cell `FirstOrDefault`; `_processingConfig.LatLonTolerance` no longer referenced at this site (DownloaderRefactorTests AZ375_AC1 passes; grep confirms `0.0001` only remains in the unrelated `ProcessingConfig` default and tests). ✓
+- AZ-377: `EarthRadiusMeters`, `EarthEquatorialCircumferenceMeters`, `MetersPerDegreeLatitude` are `public const double` on `GeoUtils`; `MapConfig.DefaultTileSizePixels` is a `public const int` mirroring the property default; all source-code occurrences of `6378137`, `40075016.686`, `111000`, and source-code occurrences of `256` are confined to those declarations (DownloaderRefactorTests + GeoUtilsRefactorTests AZ377_AC1, AC2 pass). ✓
+
+**Phase 3 — Code quality**
+- All edits under SRP — no method gained more than one responsibility; HashSet builder is a small, named, local computation in the same method; logger removal from RegionRepository/RouteRepository is purely subtractive.
+- No bare catches introduced. No new debug-noise logs. No obvious duplication.
+
+**Phase 4 — Security quick-scan**
+- No new SQL string interpolation (Dapper named params throughout, ColumnList is a `const string`, not user input).
+- No new secrets, no new external inputs.
+- Slow-query warning logs query duration and SQL text, both safe.
+
+**Phase 5 — Performance scan**
+- AZ-375 directly removes an O(N) per-cell scan inside an O(grid) loop: a region of NxN tiles previously did O(N² · existingTiles) work; now O(existingTiles) preprocessing + O(1) per cell.
+- No N+1 queries introduced; the existing-tiles query batch shape is unchanged.
+- No blocking I/O in async paths added.
+
+**Phase 6 — Cross-task consistency**
+- Batch 23 + 24 collectively touch the same three repositories and `GoogleMapsDownloaderV2`; constants moved into Common are consumed by DataAccess and the downloader uniformly. No divergent patterns.
+- AZ-379's ColumnList convention applied identically across all three repos (`private const string ColumnList = @"…"`, used via `$@"… SELECT {ColumnList} …"`).
+
+**Phase 7 — Architecture compliance**
+- Layer direction: Common (leaf) ← DataAccess ← Services.TileDownloader ← Api. All new imports respect the table.
+- Public API respect: `GeoUtils`, `MapConfig`, and their new constants are top-level public types in `Common`. No internal-file imports.
+- New cyclic deps: none introduced (DataAccess→Common is one-way; Common does not reference DataAccess).
+- Duplicate symbols: the previous duplicate Earth literals across `GoogleMapsDownloaderV2.cs` and `TileRepository.cs` are now collapsed to one declaration in `GeoUtils.cs`. The `MapConfig.TileSizePixels` property + `MapConfig.DefaultTileSizePixels` const live in the same class — see F4.
+
+## Baseline Delta
+
+| Status | Severity | Title | Note |
+|--------|----------|-------|------|
+| Carried over | Low | F5 — DataAccess Common dependency drift | Documentation drift; widened by AZ-377 (see F1 above). |
+| Resolved | Low | duplicate Earth literals across modules | Cumulative review @ batch 21 had flagged the same literals in two files; AZ-377 collapses them to a single source in `GeoUtils`. |
+| Newly introduced | — | none | No new Critical / High / Medium architectural findings. |
+
+Per-category counts (current scope):
+
+| Category | Critical | High | Medium | Low |
+|----------|----------|------|--------|-----|
+| Architecture | 0 | 0 | 0 | 1 |
+| Maintainability | 0 | 0 | 0 | 2 |
+| Spec-Gap | 0 | 0 | 0 | 1 |
+| Security | 0 | 0 | 0 | 0 |
+| Performance | 0 | 0 | 0 | 0 |
+| Bug | 0 | 0 | 0 | 0 |
+
+## Test posture
+
+- `scripts/run-tests.sh --unit-only`: 200/200 PASS (10 new tests added across batches 23-24).
+- Format gate (`dotnet format whitespace --verify-no-changes`): PASS.
+- Full smoke / integration suite: not re-run as part of this cumulative review (next session boundary will run it before commit if the engine requires).
+
+## Verdict logic
+
+- 0 Critical, 0 High, 0 Medium, 4 Low → **PASS_WITH_WARNINGS**.
+- No FAIL conditions; no auto-fix loop required.
+
+## Recommended follow-ups (non-blocking)
+
+1. Refresh `_docs/02_document/module-layout.md` and the baseline F5 entry to reflect the actual DataAccess→Common dependency (Common.Enums, Common.Configs, Common.Utils).
+2. Decide whether `MapConfig.DefaultTileSizePixels` should remain a const or be threaded through `IOptions` into DataAccess; defer until someone overrides the value in config.
+3. Consider a future task to update the AC test-count narrative across the AZ-37x tickets if/when the project does a doc-sweep.
diff --git a/_docs/_autodev_state.md b/_docs/_autodev_state.md
index 8a9160a..ab337e4 100644
--- a/_docs/_autodev_state.md
+++ b/_docs/_autodev_state.md
@@ -6,9 +6,9 @@ step: 8
 name: Refactor
 status: in_progress
 sub_step:
-  phase: 4
-  name: batch-loop
-  detail: "batch 23 complete; cum-rev counter 2/3; ready for batch 24 (AZ-375, AZ-377)"
+  phase: 5
+  name: test-sync
+  detail: ""
 retry_count: 0
 cycle: 1
 tracker: jira
diff --git a/scripts/run-tests.sh b/scripts/run-tests.sh
index 61628b8..7171e41 100755
--- a/scripts/run-tests.sh
+++ b/scripts/run-tests.sh
@@ -60,11 +60,7 @@ fi
 if [[ "$mode" == "unit" ]]; then
     echo "Running unit tests only..."
     docker run --rm -v "$PROJECT_ROOT:/src" -w /src mcr.microsoft.com/dotnet/sdk:8.0 \
-        dotnet test SatelliteProvider.Tests/SatelliteProvider.Tests.csproj \
-        --no-restore --configuration Release \
-        --collect:"XPlat Code Coverage" \
-        --results-directory /src/TestResults \
-        --logger "console;verbosity=normal"
+        sh -c "dotnet restore SatelliteProvider.sln && dotnet test SatelliteProvider.Tests/SatelliteProvider.Tests.csproj --no-restore --configuration Release --collect:'XPlat Code Coverage' --results-directory /src/TestResults --logger 'console;verbosity=normal'"
     echo ""
     echo "=== Unit tests complete (coverage written to ./TestResults/) ==="
     exit 0