fix: read nodata from tiff

linz · Mar 15, 2020 · 64d3e9c · 64d3e9c
1 parent 6922bd8
commit 64d3e9c
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Showing 5 changed files with 33 additions and 5 deletions.
diff --git a/packages/cog/src/builder.ts b/packages/cog/src/builder.ts
@@ -24,6 +24,9 @@ export interface CogBuilderBounds {
 
     /** EPSG projection number */
     projection: number;
+
+    /** GDAL_NODATA value */
+    nodata: number;
 }
 export const InvalidProjectionCode = 32767;
 export const CacheFolder = './.cache';
@@ -51,6 +54,7 @@ export class CogBuilder {
         let resolution = -1;
         let bandCount = -1;
         let projection = -1;
+        let nodata = -1;
         let count = 0;
         const coordinates = sources.map(source => {
             return this.q(async () => {
@@ -83,13 +87,22 @@ export class CogBuilder {
                     projection = imageProjection;
                 }
 
+                const noData = this.findNoData(tiff);
+                if (noData != null && noData != projection) {
+                    if (nodata != -1) {
+                        throw new Error('Multiple No Data values');
+                    }
+                    nodata = noData;
+                }
+
                 return output;
             });
         });
 
         const polygons = await Promise.all(coordinates);
         return {
             projection,
+            nodata,
             bands: bandCount,
             bounds: GeoJson.toFeatureCollection(polygons),
             resolution,
@@ -135,6 +148,14 @@ export class CogBuilder {
         throw new Error('Failed to find projection');
     }
 
+    /**
+     * Get the nodata value stored in the source tiff
+     * @param tiff
+     */
+    findNoData(tiff: CogTiff): number {
+        return tiff.getImage(0).value(TiffTag.GDAL_NODATA) ?? 255;
+    }
+
     /**
      * Generate the bounding boxes for a GeoTiff converting to WGS84
      * @param tiff

diff --git a/packages/cog/src/cli/actions/action.cog.ts b/packages/cog/src/cli/actions/action.cog.ts
@@ -11,7 +11,6 @@ export class ActionCogCreate extends CommandLineAction {
     private quadKey?: CommandLineStringParameter;
     private commit?: CommandLineFlagParameter;
     private quadKeyIndex?: CommandLineIntegerParameter;
-    private resampleMethod?: CommandLineStringParameter;
 
     public constructor() {
         super({

diff --git a/packages/cog/src/cli/actions/action.job.ts b/packages/cog/src/cli/actions/action.job.ts
@@ -3,7 +3,12 @@ import { FileConfig, FileOperator, FileOperatorS3, LogConfig } from '@basemaps/l
 import { CogSource } from '@cogeotiff/core';
 import { CogSourceAwsS3 } from '@cogeotiff/source-aws';
 import { CogSourceFile } from '@cogeotiff/source-file';
-import { CommandLineAction, CommandLineFlagParameter, CommandLineIntegerParameter, CommandLineStringParameter } from '@microsoft/ts-command-line';
+import {
+    CommandLineAction,
+    CommandLineFlagParameter,
+    CommandLineIntegerParameter,
+    CommandLineStringParameter,
+} from '@microsoft/ts-command-line';
 import { createReadStream, promises as fs } from 'fs';
 import { basename } from 'path';
 import * as ulid from 'ulid';
@@ -131,6 +136,7 @@ export class ActionJobCreate extends CommandLineAction {
         const metadata = await builder.build(tiffSource, logger);
 
         const logObj = { ...metadata };
+        const nodata = metadata.nodata;
         delete logObj.bounds; // Don't log bounds as it is huge
         logger.info(logObj, 'CoveringGenerated');
 
@@ -148,7 +154,7 @@ export class ActionJobCreate extends CommandLineAction {
             );
         }
 
-        const vrtOptions: VrtOptions = { addAlpha: true, forceEpsg3857: true, forceNoData255: true };
+        const vrtOptions: VrtOptions = { addAlpha: true, forceEpsg3857: true, forceNoData: true };
         // -addalpha to vrt adds extra alpha layers even if one already exist
         if (metadata.bands > 3) {
             logger.warn({ bandCount: metadata.bands }, 'Vrt:DetectedAlpha, Disabling -addalpha');
@@ -167,6 +173,7 @@ export class ActionJobCreate extends CommandLineAction {
             output: {
                 ...outputConfig,
                 resample: getResample(this.resample?.value),
+                nodata: nodata,
                 vrt: {
                     options: vrtOptions,
                 },

diff --git a/packages/cog/src/cog.ts b/packages/cog/src/cog.ts
@@ -33,6 +33,7 @@ export interface CogJob {
     /** Folder/S3 bucket to store the output */
     output: {
         resample: GdalCogBuilderOptionsResampling;
+        nodata: number;
         vrt: {
             options: VrtOptions;
         };

diff --git a/packages/cog/src/cog.vrt.ts b/packages/cog/src/cog.vrt.ts
@@ -90,8 +90,8 @@ export async function buildWarpedVrt(
     gdalCommand.parser.on('progress', onProgress({ target: `vrt.${EPSG.Google}` }, logger));
 
     const warpOpts = ['-of', 'VRT', '-t_srs', Projection.toEpsgString(EPSG.Google), vrtPath, vrtWarpedPath];
-    if (options.forceNoData255) {
-        warpOpts.push('-srcnodata', '255', '-dstnodata', '255');
+    if (options.forceNoData) {
+        warpOpts.push('-srcnodata', String(job.output.nodata), '-dstnodata', String(job.output.nodata));
     }
     if (job.output.resample) {
         warpOpts.push('-r', job.output.resample);