GDAL for wasm

compile and run

1. install emscripten

   see https://github.com/kripken/emscripten\

   tested emscripten version:

   emcc (Emscripten gcc/clang-like replacement + linker emulating GNU ld) 3.1.25 (febd44b21ecaca86e2cb2a25ef3ed4a0a2076365) clang version 16.0.0 (https://github.com/llvm/llvm-project effd75bda4b1a9b26e554c1cda3e3b4c72fa0aa8)

2. compile gdal and proj for multi-thread

   make

3. install gdal and proj headers

   cd gdal && make install

   The lib can befound:

   • proj4/src/.libs/libproj.a
   • gdal/libgdal.a

This is a part of GPlates wasm project.

GDAL JS

============== An Emscripten port of GDAL 2.4.

Installation

npm install gdal-js

Usage

Caution! It is strongly recommended to run this code inside of a web worker. To see complete examples for how to do this, checkout the examples directory. From simplest to most complex, these are:

1. inspect_geotiff
2. inspect_vector
3. map_extent
4. thumbnail
5. thumbnail_map
6. tile_tiff

If you want to use GDAL from within a Node application, you are probably looking for https://www.npmjs.com/package/gdal.

This library exports the following GDAL functions:

• CSLCount
• GDALSetCacheMax
• GDALAllRegister
• GDALOpen
• GDALOpenEx
• GDALClose
• GDALGetDriverByName
• GDALCreate
• GDALCreateCopy
• GDALGetRasterXSize
• GDALGetRasterYSize
• GDALGetRasterCount
• GDALGetRasterDataType
• GDALGetRasterBand
• GDALGetRasterStatistics
• GDALGetRasterMinimum
• GDALGetRasterMaximum
• GDALGetRasterNoDataValue
• GDALGetDataTypeSizeBytes
• GDALGetDataTypeByName
• GDALGetDataTypeName
• GDALRasterIO
• GDALRasterIOEx
• GDALReadBlock
• GDALWriteBlock
• GDALGetBlockSize
• GDALGetActualBlockSize
• GDALGetProjectionRef
• GDALSetProjection
• GDALGetGeoTransform
• GDALSetGeoTransform
• OSRNewSpatialReference
• OSRDestroySpatialReference
• OSRImportFromEPSG
• OCTNewCoordinateTransformation
• OCTDestroyCoordinateTransformation
• OCTTransform
• GDALCreateGenImgProjTransformer
• GDALDestroyGenImgProjTransformer
• GDALGenImgProjTransform
• GDALDestroyGenImgProjTransformer
• GDALSuggestedWarpOutput
• GDALTranslate
• GDALTranslateOptionsNew
• GDALTranslateOptionsFree
• GDALWarpAppOptionsNew
• GDALWarpAppOptionsSetProgress
• GDALWarpAppOptionsFree
• GDALWarp
• GDALBuildVRTOptionsNew
• GDALBuildVRTOptionsFree
• GDALBuildVRT
• GDALReprojectImage
• CPLError
• CPLSetErrorHandler
• CPLQuietErrorHandler
• CPLErrorReset
• CPLGetLastErrorMsg
• CPLGetLastErrorNo
• CPLGetLastErrorType
• GDALRasterize
• GDALRasterizeOptionsNew
• GDALRasterizeOptionsFree
• GDALDEMProcessing
• GDALDEMProcessingOptionsNew
• GDALDEMProcessingOptionsFree
• GDALDatasetGetLayer
• GDALDatasetGetLayerByName
• GDALDatasetGetLayerCount
• GDALDatasetExecuteSQL
• GDALRasterIO
• GDALRasterIOEx
• GDALDatasetRasterIO
• GDALDatasetRasterIOEx
• GDALReadBlock
• GDALWriteBlock
• GDALGetBlockSize
• GDALGetActualBlockSize
• OGR_L_GetNextFeature
• OGR_L_GetExtent
• OGR_L_GetLayerDefn
• OGR_L_ResetReading
• OGR_L_GetName
• OGR_F_GetFieldAsInteger
• OGR_F_GetFieldAsInteger64
• OGR_F_GetFieldAsDouble
• OGR_F_GetFieldAsString
• OGR_F_GetFieldAsBinary
• OGR_F_GetFieldAsDateTime
• OGR_F_GetFieldAsDateTimeEx
• OGR_F_GetFieldAsDoubleList
• OGR_F_GetFieldAsIntegerList
• OGR_F_GetFieldAsInteger64List
• OGR_F_GetFieldAsStringList
• OGR_F_GetGeometryRef
• OGR_F_Destroy
• OGR_FD_GetFieldCount
• OGR_FD_GetFieldDefn
• OGR_Fld_GetType
• OGR_Fld_GetNameRef
• OGR_G_GetGeometryType
• OGR_G_GetX
• OGR_G_GetY
• OGR_G_GetPoint
• OGR_G_GetPoints
• OGR_G_GetPointCount
• OGR_G_GetEnvelope
• OGR_G_GetSpatialReference
• OGR_G_Intersects
• OGR_G_Simplify
• OGR_G_Touches
• OGR_G_Transform
• OGR_G_Within
• OGR_G_ExportToGML
• OGR_G_ExportToJson
• OGR_G_ExportToJsonEx
• OGR_G_ExportToKML
• OGR_G_ExportToWkb
• OGR_G_ExportToWkt
• GDALVectorTranslate (ogr2ogr)
• GDALVectorTranslateOptionsFree
• GDALVectorTranslateOptionsNew
• GDALVectorTranslateOptionsSetProgress
• GDALPolygonize
• GDALFPolygonize
• GDALSieveFilter

For documentation of these functions' behavior, please see the GDAL documentation

In order to limit build size, GDAL is currently built with raster support for GeoTIFFs, PNGs, and JPEGs only.

Developing

1. Install Docker
2. Run ./scripts/setup, which will build the Docker container.
3. Run ./scripts/make gdal. The make script just calls make from inside the Docker container.
4. ./scripts/make clean works as expected.
5. To package up a release, run ./scripts/make VERSION=<number> release