Take the scan waypoints only from the CSV file, never generate them

config/config.example.ini

@@ -206,19 +206,17 @@ homing_timeout_s = 65
 
 [Scan]
 ; Capture scan grid (the (yaw,pitch) waypoints auto-sweep steps through).
-; If grid_file is set, that CSV is used verbatim (one "yaw_deg,pitch_deg" per
-; line, '#' comments allowed) - edit it to define exact scan coordinates.
-; If grid_file is blank, a grid is generated: yaw_intervals positions across
-; [yaw_min_deg, yaw_max_deg] at each pitch level.
+; grid_file is the ONLY source: that CSV is used verbatim (one
+; "yaw_deg,pitch_deg" per line, '#' comments allowed). Nothing is generated -
+; leave it blank and auto-sweep stays off with a message saying so, rather than
+; the tower inventing an arc nobody chose.
+; A relative path resolves against the directory of the config file it is
+; written in (config.ini sits at the repo root, so: config/scan.csv).
 ; The sweep always runs front to back, then returns to the first waypoint and
 ; repeats, so every pass captures the waypoints in the same order. The return
 ; leg is one long slew (the yaw arc cannot wrap), so order the grid with that
 ; in mind.
-grid_file =
-yaw_intervals = 56
-yaw_min_deg = -90
-yaw_max_deg = 90
-pitch_levels = 10,30,50
+grid_file = config/scan.csv
 
 [Paths]
 ; Directory for saved .jxl images. Supports leading ~ and $ENV expansion.

config/scan-staeffelsberg.csv

@@ -0,0 +1,64 @@
+# Staeffelsberg scan grid: 56 bearings round the full circle at one elevation,
+# matching the old firmware's 'ud56' sweep. Generated once from the retired
+# [Scan] grid generator (0 -> 353.57 deg in 56 steps, pitch 0) and kept here as
+# the explicit list, because the CSV is now the only source of waypoints.
+#
+# The sweep runs first to last, then returns to the first and repeats - always
+# the same order, never in reverse. The return leg is one long slew back across
+# the arc; that is the price of every pass being directly comparable.
+0.00,0
+6.43,0
+12.86,0
+19.29,0
+25.71,0
+32.14,0
+38.57,0
+45.00,0
+51.43,0
+57.86,0
+64.29,0
+70.71,0
+77.14,0
+83.57,0
+90.00,0
+96.43,0
+102.86,0
+109.29,0
+115.71,0
+122.14,0
+128.57,0
+135.00,0
+141.43,0
+147.86,0
+154.29,0
+160.71,0
+167.14,0
+173.57,0
+180.00,0
+186.43,0
+192.86,0
+199.28,0
+205.71,0
+212.14,0
+218.57,0
+225.00,0
+231.43,0
+237.86,0
+244.28,0
+250.71,0
+257.14,0
+263.57,0
+270.00,0
+276.43,0
+282.86,0
+289.28,0
+295.71,0
+302.14,0
+308.57,0
+315.00,0
+321.43,0
+327.86,0
+334.28,0
+340.71,0
+347.14,0
+353.57,0

config/scan.csv

@@ -1,24 +1,30 @@
-# Scan grid — capture waypoints," one ""yaw_deg","pitch_deg"" per line."
-# Edit these to define the exact scan coordinates. Blank lines and lines,,
-# starting with '#' are ignored. The auto-sweep (ControlCode 0) walks the list,,
-# forward then backward (ping-pong), triggering the cameras at each settled,
-# point. Degrees are converted to encoder counts via the [Motor] calibration.,,
-#,,
-# Reference this file from config.ini:  [Scan] grid_file = config/scan.csv,,
-#,,
-# Example: three elevation rows across a 180° yaw arc.,,
-0,10,
-45,10,
-90,10,
-135,10,
-180,10,
-0,5,
-45,5,
-90,5,
-135,5,
-180,5,
-0,15,
-45,15,
-90,15,
-135,15,
-180,15,
+# Scan grid - capture waypoints, one "yaw_deg,pitch_deg" per line.
+# Edit these to define the exact scan coordinates. Blank lines and lines
+# starting with '#' are ignored. This file is the only source of waypoints:
+# nothing is generated, so what the tower photographs is always what is written
+# here.
+#
+# The auto-sweep (ControlCode 0) walks the list from the first waypoint to the
+# last, triggering the cameras at each settled point, then returns to the first
+# and repeats - always in the same order, never in reverse. That return leg is
+# one long slew (the yaw arc cannot wrap), so order the list with it in mind.
+# Degrees are converted to encoder counts via the [Motor] calibration.
+#
+# Reference this file from config.ini:  [Scan] grid_file = config/scan.csv
+#
+# Example: three elevation rows across a 180 deg yaw arc.
+0,10
+45,10
+90,10
+135,10
+180,10
+0,5
+45,5
+90,5
+135,5
+180,5
+0,15
+45,15
+90,15
+135,15
+180,15

docs/configuration.md

@@ -86,10 +86,7 @@ Parsed and validated by `ConfigLoader` ([src/core/Config.cpp](../src/core/Config
 | `Motor.<axis>` | `enc_deviation` | int | — | \|XACTUAL−XENC\| that means "position untrustworthy". **hardware.ini** |
 | `Motor.<axis>` | `enc_const` | float | 12.8 | Microsteps per encoder count (the TMC's `ENC_CONST`), up to 4 decimals. **hardware.ini**, optional: only a drivetrain whose encoder differs declares it. Wrong by a few percent, the step counter and encoder drift apart as the axis turns, and homing takes the drift for a stop (staeffelsberg: 12.5, from its old firmware) |
 | `Motor.<axis>` | `sw_mode` / `has_encoder` | int / bool | — | TMC `SW_MODE` (physical endstop switches on REFL/REFR) and whether this axis's encoder is aligned and usable. **hardware.ini** |
-| `Scan` | `grid_file` | string | — | CSV of `yaw_deg,pitch_deg` waypoints; empty → generate |
-| `Scan` | `yaw_intervals` | int | `56` | Generated yaw positions across `[yaw_min_deg, yaw_max_deg]` |
-| `Scan` | `yaw_min_deg`/`yaw_max_deg` | float | `-90`/`90` | Generated yaw arc |
-| `Scan` | `pitch_levels` | csv | `0` | Generated pitch elevations (deg) |
+| `Scan` | `grid_file` | string | — | CSV of `yaw_deg,pitch_deg` waypoints. The only source of a scan grid; empty → auto-sweep disabled |
 
 ### `[Motor]` calibration & `[Scan]` grid
 
@@ -179,15 +176,21 @@ the tower can measure it. Yaw is untouched by it.
 #### Scan grid
 
 The capture **scan grid** is the ordered `(yaw,pitch)` waypoints auto-sweep visits, always front to
-back. Set `[Scan] grid_file` to an editable CSV ([config/scan.csv](../config/scan.csv)) to define exact
-coordinates, or leave it blank to generate `yaw_intervals × pitch_levels` points.
+back, then round to the first again — never in reverse. `[Scan] grid_file` points at an editable CSV
+([config/scan.csv](../config/scan.csv)) and is the **only** source of waypoints.
+
+**Nothing is generated.** Leave `grid_file` blank (or name a file that is missing, malformed or
+empty) and the program logs why and leaves auto-sweep off, showing the reason in the TUI's scan-grid
+panel. A tower that invented its own arc would archive images under bearings nobody chose, with no
+file to read back to find out what was photographed. The pre-2026-09 keys `yaw_intervals`,
+`yaw_min_deg`, `yaw_max_deg` and `pitch_levels` are gone; a config still carrying them gets a
+startup warning naming them.
 
 **Grid yaw values are true bearings.** Yaw travel is under a full turn, so there is always an
 unreachable arc; waypoints falling in it are **skipped** with a warning rather than clamped to the
 nearest limit — clamping would image a direction nobody asked for and publish it under the bearing
-they did. A one-line audit after each home reports how many waypoints are affected. Generated grids
-interpolate `yaw_min_deg → yaw_max_deg` linearly and wrap each point, so an arc crossing north is
-written monotonically (`340` → `380`).
+they did. A one-line audit after each home reports how many waypoints are affected. Write an arc
+crossing north monotonically (`340` → `380`) rather than letting it wrap back through zero.
 
 Each camera's output subfolder is its `[Camera.<name>] label` (defaulting to the block name); nothing is derived from the order of the blocks.
 

docs/modules-reference.md

@@ -11,7 +11,7 @@ Per-file reference for the refactored tree, plus the shared data structures.
 | [include/fgc/Logger.h](../include/fgc/Logger.h), [src/core/Logger.cpp](../src/core/Logger.cpp) | Leveled, thread-safe logger + per-category wire trace; `LOG_TRACE..LOG_ERROR`, `LOG_TRACE_CAT` |
 | [include/fgc/FileLogSink.h](../include/fgc/FileLogSink.h), [src/core/FileLogSink.cpp](../src/core/FileLogSink.cpp) | The persistent log file: append, size rotation, count-based pruning, a self-describing header per file. Runs inside `Logger`'s non-recursive lock, so it never logs - failures latch into `failed()`/`lastError()` for the caller to report |
 | [include/fgc/Geometry.h](../include/fgc/Geometry.h), [src/core/Geometry.cpp](../src/core/Geometry.cpp) | Per-axis degrees↔encoder-counts affine map (`[Motor]` calibration) |
-| [include/fgc/ScanGrid.h](../include/fgc/ScanGrid.h), [src/core/ScanGrid.cpp](../src/core/ScanGrid.cpp) | Capture waypoints (CSV or generated) + one-way wrapping cursor (`[Scan]`) |
+| [include/fgc/ScanGrid.h](../include/fgc/ScanGrid.h), [src/core/ScanGrid.cpp](../src/core/ScanGrid.cpp) | Capture waypoints (CSV only, never generated) + one-way wrapping cursor (`[Scan]`) |
 | [include/fgc/TelemetryParser.h](../include/fgc/TelemetryParser.h), [src/core/TelemetryParser.cpp](../src/core/TelemetryParser.cpp) | `parseTelemetryLine` (firmware `ST` line) → `std::optional<MotorTelemetry>` |
 | [include/fgc/CommandParser.h](../include/fgc/CommandParser.h), [src/core/CommandParser.cpp](../src/core/CommandParser.cpp) | `parseCommand` whitespace tokenizer → `Command` |
 | [include/fgc/HelpText.h](../include/fgc/HelpText.h), [src/core/HelpText.cpp](../src/core/HelpText.cpp) | Operator command catalog (`helpCatalog`) + `renderHelp` (console & TUI help) |

include/fgc/Config.h

@@ -317,14 +317,11 @@ struct UiConfig {
 };
 
 // [Scan]: source of the capture scan grid (the (yaw,pitch) waypoints the
-// auto-sweep steps through). If grid_file is set, the CSV is loaded verbatim;
-// otherwise a grid is generated from the parameters below (see ScanGrid).
+// auto-sweep steps through). The CSV is the only source - it is loaded verbatim
+// and there is no generated fallback, so what a tower photographs is always a
+// file somebody wrote and can be read back (see ScanGrid).
 struct ScanConfig {
-    std::string grid_file;                  // path to an editable yaw_deg,pitch_deg CSV; empty => generate
-    int         yaw_intervals = 56;         // generated: yaw positions across [yaw_min_deg, yaw_max_deg]
-    double      yaw_min_deg   = -90.0;
-    double      yaw_max_deg   = 90.0;
-    std::string pitch_levels  = "0";        // generated: comma list of pitch elevations (deg)
+    std::string grid_file;  // path to an editable yaw_deg,pitch_deg CSV; required for auto-sweep
 };
 
 // [Test] / [TestProfile.<name>]: the hardware self-test command. A profile is a

include/fgc/ScanGrid.h

@@ -22,15 +22,17 @@ struct ScanPoint {
 // The cost is a long return slew from the last waypoint to the first, since the
 // yaw arc is bounded and cannot wrap. Order the grid so that leg is acceptable.
 //
-// Points come either from an operator-edited CSV (ScanConfig::grid_file) or, if
-// none is given, are generated from the [Scan] parameters.
+// Points come from an operator-edited CSV (ScanConfig::grid_file) and nowhere
+// else. There is deliberately no fallback grid: a tower that invented its own
+// waypoints would archive images under bearings nobody chose, and the operator
+// would have no file to point at to find out what was photographed.
 class ScanGrid {
 public:
     ScanGrid() = default;
     explicit ScanGrid(std::vector<ScanPoint> points) : points_(std::move(points)) {}
 
-    // Build from config: load grid_file if set (throws std::runtime_error on a
-    // missing/!malformed file), else generate from the parameters.
+    // Load grid_file. Throws std::runtime_error if it is unset, missing,
+    // malformed or empty; the caller reports that and leaves auto-sweep off.
     static ScanGrid fromConfig(const ScanConfig& cfg);
 
     bool             empty() const { return points_.empty(); }
@@ -50,6 +52,5 @@ private:
 
 // Exposed for unit testing.
 std::vector<ScanPoint> parseScanCsv(const std::string& text);
-std::vector<ScanPoint> generateScanGrid(const ScanConfig& cfg);
 
 }  // namespace fgc

include/fgc/ui/UiSnapshot.h

@@ -157,7 +157,6 @@ struct CaptureView {
     // Defined scan grid (the auto-mode waypoints) with the live cursor
     // flagged, surfaced in the expanded camera view.
     std::vector<ScanWaypointView> scan_grid;
-    bool                          scan_from_file = false;  // grid_file CSV vs generated
     bool                          scan_pitch     = false;  // 2-axis rig (show pitch column)
     std::string                   scan_error;              // grid_file load failure (auto-sweep off)
 

src/core/Application.cpp

@@ -925,7 +925,6 @@ struct Application::Impl {
 
         // Defined scan grid + live cursor (read on the control thread, same as the
         // scheduler that mutates it, so no locking is needed).
-        s.capture.scan_from_file = !cfg.scan.grid_file.empty();
         s.capture.scan_pitch     = t.pitch_present;
         s.capture.scan_error     = scan_load_error_;
         s.capture.scan_grid.clear();

src/core/Config.cpp

@@ -521,12 +521,8 @@ AppConfig ConfigLoader::fromMap(const std::map<std::string, std::string>& kv) {
     axisDrivetrain("yaw", cfg.drivetrain.yaw);
     axisDrivetrain("pitch", cfg.drivetrain.pitch);
 
-    // [Scan]: scan-grid source (explicit CSV file, else generated).
-    cfg.scan.grid_file     = get(kv, "Scan.grid_file", cfg.scan.grid_file);
-    cfg.scan.yaw_intervals = getInt(kv, "Scan.yaw_intervals", cfg.scan.yaw_intervals);
-    cfg.scan.yaw_min_deg   = getDouble(kv, "Scan.yaw_min_deg", cfg.scan.yaw_min_deg);
-    cfg.scan.yaw_max_deg   = getDouble(kv, "Scan.yaw_max_deg", cfg.scan.yaw_max_deg);
-    cfg.scan.pitch_levels  = get(kv, "Scan.pitch_levels", cfg.scan.pitch_levels);
+    // [Scan]: the scan-grid CSV. No file, no auto-sweep - nothing is generated.
+    cfg.scan.grid_file = get(kv, "Scan.grid_file", cfg.scan.grid_file);
 
     // ---- validation ----
     if (cfg.general.image_interval <= 0)
@@ -601,6 +597,20 @@ AppConfig ConfigLoader::fromMap(const std::map<std::string, std::string>& kv) {
                     "setup'), and drivetrain keys belong under [Motor.yaw] / "
                     "[Motor.pitch], not [Motor]";
 
+    // Keys from when a blank grid_file meant "generate a grid". The generator is
+    // gone: the CSV is the only source. Ignoring these quietly would leave an
+    // operator believing they had set the scan arc when nothing reads it.
+    static const char* kRemovedScanKeys[] = {
+        "Scan.yaw_intervals", "Scan.yaw_min_deg", "Scan.yaw_max_deg", "Scan.pitch_levels",
+    };
+    std::string stale_scan;
+    for (const char* k : kRemovedScanKeys)
+        if (kv.count(k)) stale_scan += (stale_scan.empty() ? "" : ", ") + std::string(k + 5);
+    if (!stale_scan.empty())
+        LOG_WARN << "[Scan] ignoring keys nothing reads: " << stale_scan
+                 << " -- grids are no longer generated; list the waypoints in the "
+                    "grid_file CSV instead";
+
     return cfg;
 }
 

src/core/ScanGrid.cpp

@@ -16,20 +16,6 @@ std::string trim(const std::string& s) {
     return s.substr(b, e - b + 1);
 }
 
-std::vector<double> parseDoubleList(const std::string& csv) {
-    std::vector<double> out;
-    size_t start = 0;
-    while (start <= csv.size()) {
-        size_t comma = csv.find(',', start);
-        std::string tok =
-            trim(csv.substr(start, comma == std::string::npos ? std::string::npos : comma - start));
-        if (!tok.empty()) out.push_back(std::stod(tok));
-        if (comma == std::string::npos) break;
-        start = comma + 1;
-    }
-    return out;
-}
-
 }  // namespace
 
 std::vector<ScanPoint> parseScanCsv(const std::string& text) {
@@ -58,37 +44,21 @@ std::vector<ScanPoint> parseScanCsv(const std::string& text) {
     return pts;
 }
 
-std::vector<ScanPoint> generateScanGrid(const ScanConfig& cfg) {
-    std::vector<ScanPoint> pts;
-    std::vector<double> pitches = parseDoubleList(cfg.pitch_levels);
-    if (pitches.empty()) pitches.push_back(0.0);
-    int n = cfg.yaw_intervals;
-    if (n < 1) n = 1;
-    // pitch-major, yaw inner (min -> max); the runtime cursor walks the whole list in order.
-    for (double pitch : pitches) {
-        for (int i = 0; i < n; ++i) {
-            double frac = n > 1 ? static_cast<double>(i) / (n - 1) : 0.0;
-            ScanPoint p;
-            p.yaw_deg   = cfg.yaw_min_deg + frac * (cfg.yaw_max_deg - cfg.yaw_min_deg);
-            p.pitch_deg = pitch;
-            pts.push_back(p);
-        }
-    }
-    return pts;
-}
-
 ScanGrid ScanGrid::fromConfig(const ScanConfig& cfg) {
-    if (!cfg.grid_file.empty()) {
-        std::ifstream f(cfg.grid_file);
-        if (!f) throw std::runtime_error("cannot open scan grid file: " + cfg.grid_file);
-        std::stringstream buf;
-        buf << f.rdbuf();
-        auto pts = parseScanCsv(buf.str());
-        if (pts.empty())
-            throw std::runtime_error("scan grid file has no waypoints: " + cfg.grid_file);
-        return ScanGrid(std::move(pts));
-    }
-    return ScanGrid(generateScanGrid(cfg));
+    // No grid_file, no grid. Generating a default sweep here would put a tower
+    // on the air photographing bearings nobody picked, under a configuration
+    // that shows no waypoints at all; refusing leaves auto-sweep off and says
+    // exactly what is missing.
+    if (cfg.grid_file.empty())
+        throw std::runtime_error("no scan grid configured: set [Scan] grid_file to a CSV of "
+                                 "'yaw_deg,pitch_deg' waypoints (see config/scan.csv)");
+    std::ifstream f(cfg.grid_file);
+    if (!f) throw std::runtime_error("cannot open scan grid file: " + cfg.grid_file);
+    std::stringstream buf;
+    buf << f.rdbuf();
+    auto pts = parseScanCsv(buf.str());
+    if (pts.empty()) throw std::runtime_error("scan grid file has no waypoints: " + cfg.grid_file);
+    return ScanGrid(std::move(pts));
 }
 
 void ScanGrid::advance() {

src/ui/TuiUi.cpp

@@ -501,8 +501,7 @@ Element cameraDetailPanel(const CaptureView& c, ScrollState& st) {
 
     // --- Scan grid ---
     rows.push_back(separator());
-    rows.push_back(hbox({text("SCAN GRID  ") | bold | color(Color::Blue),
-                         text(c.scan_from_file ? "(CSV file)" : "(generated)") | dim, filler(),
+    rows.push_back(hbox({text("SCAN GRID  ") | bold | color(Color::Blue), filler(),
                          text(std::to_string(c.scan_grid.size()) + " waypoints") | dim}));
 
     if (!c.scan_error.empty()) {

tests/test_scangrid.cpp

@@ -2,6 +2,8 @@
 
 #include "fgc/ScanGrid.h"
 
+#include <stdexcept>
+
 using namespace fgc;
 
 TEST_CASE("parseScanCsv reads waypoints and skips comments/blanks") {
@@ -17,20 +19,18 @@ TEST_CASE("parseScanCsv throws on a malformed line") {
     CHECK_THROWS(parseScanCsv("1,abc\n"));
 }
 
-TEST_CASE("generateScanGrid produces yaw_intervals x pitch_levels points") {
+TEST_CASE("fromConfig refuses to invent a grid when no file is named") {
+    // The generator is gone on purpose: a blank grid_file must leave auto-sweep
+    // off, not produce waypoints nobody chose.
     ScanConfig c;
-    c.yaw_intervals = 3;
-    c.yaw_min_deg = -90;
-    c.yaw_max_deg = 90;
-    c.pitch_levels = "10,30";
-    auto pts = generateScanGrid(c);
-    REQUIRE(pts.size() == 6);
-    // pitch-major, yaw inner (min -> max)
-    CHECK(pts[0].yaw_deg == doctest::Approx(-90.0));
-    CHECK(pts[0].pitch_deg == doctest::Approx(10.0));
-    CHECK(pts[1].yaw_deg == doctest::Approx(0.0));
-    CHECK(pts[2].yaw_deg == doctest::Approx(90.0));
-    CHECK(pts[3].pitch_deg == doctest::Approx(30.0));
+    CHECK(c.grid_file.empty());
+    CHECK_THROWS_AS(ScanGrid::fromConfig(c), std::runtime_error);
+}
+
+TEST_CASE("fromConfig reports a grid_file that is not there") {
+    ScanConfig c;
+    c.grid_file = "/nonexistent/definitely-not-a-scan-grid.csv";
+    CHECK_THROWS_AS(ScanGrid::fromConfig(c), std::runtime_error);
 }
 
 TEST_CASE("ScanGrid cursor always runs front to back") {