feat: Handle 1:50k imagery TDE-1014 (#855)

#### Motivation In addition to accepting the 50k grid size, this also produces tile names which consist of only the sheet code for 50k imagery. To do this efficiently the code irrelevant to this simpler code path have been rearranged to avoid unnecessary computation. #### Checklist - [x] Tests updated - [ ] Docs updated (undocumented) - [x] Issue linked in Title
linz · Feb 11, 2024 · 8be7266 · 8be7266
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Showing 4 changed files with 73 additions and 29 deletions.
diff --git a/src/commands/tileindex-validate/__test__/tileindex.validate.test.ts b/src/commands/tileindex-validate/__test__/tileindex.validate.test.ts
@@ -44,6 +44,11 @@ describe('getTileName', () => {
     assert.equal(convertTileName('CH11_1000_1010', 10000), 'CH11_10000_0101');
     assert.equal(convertTileName('CH11_1000_1001', 10000), 'CH11_10000_0101');
   });
+  it('should get correct parent tile 1:50k', () => {
+    assert.equal(convertTileName('AT24_50000_0101', 50000), 'AT24');
+    assert.equal(convertTileName('AT25_50000_0101', 50000), 'AT25');
+    assert.equal(convertTileName('CK08_50000_0101', 50000), 'CK08');
+  });
 });
 describe('tiffLocation', () => {
   it('get location from tiff', async () => {
@@ -230,7 +235,7 @@ describe('GridSizeFromString', () => {
   it('should throw error when converting invalid grid size', async () => {
     await assert.rejects(
       GridSizeFromString.from('-1'),
-      new Error('Invalid grid size "-1"; valid values: "10000", "5000", "2000", "1000", "500"'),
+      new Error('Invalid grid size "-1"; valid values: "50000", "10000", "5000", "2000", "1000", "500"'),
     );
   });
 });
diff --git a/src/commands/tileindex-validate/tileindex.validate.ts b/src/commands/tileindex-validate/tileindex.validate.ts
@@ -8,7 +8,7 @@ import { logger } from '../../log.js';
 import { isArgo } from '../../utils/argo.js';
 import { FileFilter, getFiles } from '../../utils/chunk.js';
 import { findBoundingBox } from '../../utils/geotiff.js';
-import { GridSize, gridSizes, MapSheet, SheetRanges } from '../../utils/mapsheet.js';
+import { GridSize, gridSizes, MapSheet, mapSheetTileGridSize, SheetRanges } from '../../utils/mapsheet.js';
 import { config, createTiff, forceOutput, registerCli, verbose } from '../common.js';
 import { CommandListArgs } from '../list/list.js';
 
@@ -310,7 +310,7 @@ export async function extractTiffLocations(
         // if (shouldValidate) {
         //   // Is the tiff bounding box the same as the mapsheet bounding box!
         //   // Also need to allow for ~1.5cm of error between bounding boxes.
-        //   // assert bbox == MapSheet.extract(tileName).bbox
+        //   // assert bbox == MapSheet.getMapTileIndex(tileName).bbox
         // }
         return { bbox, source: tiff.source.url.href, tileName, epsg: tiff.images[0]?.epsg };
       } catch (e) {
@@ -353,32 +353,36 @@ export function validateTiffAlignment(tiff: TiffLocation, allowedError = 0.015):
 }
 
 export function getTileName(x: number, y: number, gridSize: GridSize): string {
-  const tilesPerMapSheet = Math.floor(MapSheet.gridSizeMax / gridSize);
-  const tileWidth = Math.floor(MapSheet.width / tilesPerMapSheet);
-  const tileHeight = Math.floor(MapSheet.height / tilesPerMapSheet);
-  let nbDigits = 2;
-  if (gridSize === 500) {
-    nbDigits = 3;
-  }
-
   if (!(SHEET_MIN_X <= x && x <= SHEET_MAX_X)) {
     throw new Error(`x must be between ${SHEET_MIN_X} and ${SHEET_MAX_X}, was ${x}`);
   }
   if (!(SHEET_MIN_Y <= y && y <= SHEET_MAX_Y)) {
     throw new Error(`y must be between ${SHEET_MIN_Y} and ${SHEET_MAX_Y}, was ${y}`);
   }
 
-  // Do some maths
   const offsetX = Math.round(Math.floor((x - MapSheet.origin.x) / MapSheet.width));
   const offsetY = Math.round(Math.floor((MapSheet.origin.y - y) / MapSheet.height));
-  const maxY = MapSheet.origin.y - offsetY * MapSheet.height;
-  const minX = MapSheet.origin.x + offsetX * MapSheet.width;
-  const tileX = Math.round(Math.floor((x - minX) / tileWidth + 1));
-  const tileY = Math.round(Math.floor((maxY - y) / tileHeight + 1));
 
   // Build name
   const letters = Object.keys(SheetRanges)[offsetY];
   const sheetCode = `${letters}${`${offsetX}`.padStart(2, '0')}`;
+  if (gridSize === mapSheetTileGridSize) {
+    // Shorter tile names for 1:50k
+    return sheetCode;
+  }
+
+  const tilesPerMapSheet = Math.floor(MapSheet.gridSizeMax / gridSize);
+  const tileWidth = Math.floor(MapSheet.width / tilesPerMapSheet);
+  const tileHeight = Math.floor(MapSheet.height / tilesPerMapSheet);
+
+  let nbDigits = 2;
+  if (gridSize === 500) {
+    nbDigits = 3;
+  }
+  const maxY = MapSheet.origin.y - offsetY * MapSheet.height;
+  const minX = MapSheet.origin.x + offsetX * MapSheet.width;
+  const tileX = Math.round(Math.floor((x - minX) / tileWidth + 1));
+  const tileY = Math.round(Math.floor((maxY - y) / tileHeight + 1));
   const tileId = `${`${tileY}`.padStart(nbDigits, '0')}${`${tileX}`.padStart(nbDigits, '0')}`;
   return `${sheetCode}_${gridSize}_${tileId}`;
 }
diff --git a/src/utils/__test__/mapsheet.test.ts b/src/utils/__test__/mapsheet.test.ts
@@ -5,7 +5,7 @@ import { MapSheet, MapTileIndex } from '../mapsheet.js';
 import { MapSheetData } from './mapsheet.data.js';
 
 describe('MapSheets', () => {
-  it('should extract mapsheet', () => {
+  it('should extract MapTileIndex from 1:500 tile filename', () => {
     assert.deepEqual(MapSheet.getMapTileIndex('2022_CG10_500_080037.tiff'), {
       mapSheet: 'CG10',
       gridSize: 500,
@@ -18,6 +18,24 @@ describe('MapSheets', () => {
       bbox: [1236640, 4837200, 1236880, 4837560],
     });
   });
+  it('should extract MapTileIndex from 1:50k tile filename', () => {
+    assert.deepEqual(MapSheet.getMapTileIndex('AS21.tiff'), {
+      mapSheet: 'AS21',
+      gridSize: 50_000,
+      x: 1_492_000, // MapSheet.offset('AS21').x
+      y: 6_234_000, // MapSheet.offset('AS21').y
+      name: 'AS21',
+      origin: { x: 1_492_000, y: 6_234_000 }, // MapSheet.offset('AS21')
+      width: 24_000, // MapSheet.width
+      height: 36_000, // MapSheet.height
+      bbox: [
+        1_492_000, // MapSheet.offset('AS21').x
+        6_198_000, // MapSheet.offset('AS21').y - MapSheet.height
+        1_516_000, // MapSheet.offset('AS21').x + MapSheet.width
+        6_234_000, // MapSheet.offset('AS21').y
+      ],
+    });
+  });
 
   it('should calculate offsets', () => {
     assert.deepEqual(MapSheet.offset('AS00'), { x: 988000, y: 6234000 });

diff --git a/src/utils/mapsheet.ts b/src/utils/mapsheet.ts
@@ -1,5 +1,5 @@
 /** Parse topographic mapsheet names in the format `${mapSheet}_${gridSize}_${y}${x}` */
-const MapSheetRegex = /([A-Z]{2}\d{2})_(\d+)_(\d+)/;
+const MapSheetRegex = /(?<sheetCode>[A-Z]{2}\d{2})(_(?<gridSize>\d+)_(?<tileId>\d+))?/;
 
 export interface MapTileIndex {
   /**
@@ -56,7 +56,8 @@ export type Bounds = Point & Size;
 const charA = 'A'.charCodeAt(0);
 const charS = 'S'.charCodeAt(0);
 
-export const gridSizes = [10_000, 5_000, 2_000, 1_000, 500] as const;
+export const mapSheetTileGridSize = 50_000;
+export const gridSizes = [mapSheetTileGridSize, 10_000, 5_000, 2_000, 1_000, 500] as const;
 export type GridSize = (typeof gridSizes)[number];
 
 /**
@@ -81,12 +82,12 @@ export const MapSheet = {
   /** Width of Topo 1:50k mapsheets (meters) */
   width: 24_000,
   /** Base scale Topo 1:50k mapsheets (meters) */
-  scale: 50_000,
+  scale: mapSheetTileGridSize,
   /** Map Sheets start at AS and end at CK */
   code: { start: 'AS', end: 'CK' },
   /** The top left point for where map sheets start from in NZTM2000 (EPSG:2193) */
   origin: { x: 988000, y: 6234000 },
-  gridSizeMax: 50000,
+  gridSizeMax: mapSheetTileGridSize,
   roundCorrection: 0.01,
   /** Allowed grid sizes, these should exist in the LINZ Data service (meters) */
   gridSizes: gridSizes,
@@ -96,17 +97,20 @@ export const MapSheet = {
    *
    * @example
    * ```typescript
-   * MapSheet.extract("BP27_1000_4817.tiff") // { mapSheet: "BP27", gridSize: 1000, x: 17, y:48 }
+   * MapSheet.getMapTileIndex("BP27_1000_4817.tiff") // { mapSheet: "BP27", gridSize: 1000, x: 17, y:48 }
    * ```
    */
   getMapTileIndex(fileName: string): MapTileIndex | null {
     const match = fileName.match(MapSheetRegex);
     if (match == null) return null;
-    if (match[1] == null) return null;
 
+    const sheetCode = match?.groups?.['sheetCode'];
+    if (sheetCode == null) return null;
+
+    const gridSize = Number(match?.groups?.['gridSize'] ?? mapSheetTileGridSize);
     const out: MapTileIndex = {
-      mapSheet: match[1],
-      gridSize: Number(match[2]),
+      mapSheet: sheetCode,
+      gridSize: gridSize,
       x: -1,
       y: -1,
       name: match[0],
@@ -115,13 +119,26 @@ export const MapSheet = {
       height: 0,
       bbox: [0, 0, 0, 0],
     };
+
+    const mapSheetOffset = MapSheet.offset(sheetCode);
+    if (out.gridSize === mapSheetTileGridSize) {
+      out.y = mapSheetOffset.y;
+      out.x = mapSheetOffset.x;
+      out.origin = mapSheetOffset;
+      out.width = MapSheet.width;
+      out.height = MapSheet.height;
+      // As in NZTM negative Y goes north, the minY is actually the bottom right point
+      out.bbox = [out.origin.x, out.origin.y - out.height, out.origin.x + out.width, out.origin.y];
+      return out;
+    }
+
     // 1:500 has X/Y is 3 digits not 2
     if (out.gridSize === 500) {
-      out.y = Number(match[3]?.slice(0, 3));
-      out.x = Number(match[3]?.slice(3));
+      out.y = Number(match?.groups?.['tileId']?.slice(0, 3));
+      out.x = Number(match?.groups?.['tileId']?.slice(3));
     } else {
-      out.y = Number(match[3]?.slice(0, 2));
-      out.x = Number(match[3]?.slice(2));
+      out.y = Number(match?.groups?.['tileId']?.slice(0, 2));
+      out.x = Number(match?.groups?.['tileId']?.slice(2));
     }
     if (isNaN(out.gridSize) || isNaN(out.x) || isNaN(out.y)) return null;