This is not an issue, but want some help. I want to read part of the image from the large geotiff with resampling to some scaling.

• upsampling: The read window is (0, 0, 1024, 1024) and the out image shape is 2048x2048.
• downsampling: The read window is (0, 0, 2048, 2048) and the out image shape is 1024x1024.

And both the output image's bbox is same. How can I get this?

Could you do me a favor?

Hello Thomas,

When used within a tile server, it happens often that tile requests get canceled by OpenLayers or Leaflet when the user pans/zooms faster than the server throughput. godal does not support context cancellation, what can waste (a lot of) resources in such cases. Cancelling early could be quite beneficial.

Obviously, one cannot cancel a cgo call from the go runtime and I expect an implementation in C++ to be complex. However, one could still cancel early at the io level (in osio), resulting in resource savings.

I did a dumb example at the Adapter level. Basically, the idea is to combine the key with a context id, to register the context in a global map and to fetch it when doing io in osio.

var mutex sync.Mutex
var contexts map[string]context.Context

func unwrapkey(key string) string {
	last := strings.LastIndex(key, "#")
	if last != -1 {
		key = key[:last]
	}
	return key
}

func WithContext(ctx context.Context, key string) string {
	mutex.Lock()
	defer mutex.Unlock()

	cid := uuid.New().String()
	contexts[cid] = ctx
	return fmt.Sprintf("%s#%s", key, cid)
}

func GetContext(key string) (context.Context, string) {
	mutex.Lock()
	defer mutex.Unlock()

	last := strings.LastIndex(key, "#")
	if last == -1 {
		return context.Background(), key
	}
	ctx, ok := contexts[key[last+1:]]
	if !ok {
		ctx = context.Background()
	}
	key = key[:last]
	return ctx, key
}

func init() {
	contexts = map[string]context.Context{}
	// todo: launch goroutine and clean done contexts
}

type KeyStreamerAt interface {
	StreamAt(ctx context.Context, key string, off int64, n int64) (io.ReadCloser, int64, error)
}

func (a *Adapter) srcStreamAt(key string, off int64, n int64) (io.ReadCloser, error) {
	ctx, key := GetContext(key)
        ...
}

As simple as it may be, it works well enough. We could imagine WarpWithContext(ctx, ...), etc. Hope all of this makes sense. Thomas

this is the code :

package main

import (
	"github.com/airbusgeo/godal"
)

func main() {
	godal.RegisterAll()
	tifname := "aa.tif"
	dsTif, _ := godal.Create(godal.GTiff, tifname, 1, godal.Byte, 20, 20)  // work
	dsTif.Close()

	jpegname := "bb.jpg"
	dsJpg, _ := godal.Create(godal.OpenJPEG, jpegname, 1, godal.Byte, 20, 20) // not work
	dsJpg.Close()
}

the error is

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x4430e42]

goroutine 1 [running]:
github.com/airbusgeo/godal.(*Dataset).Close(0x0, 0x0, 0x0, 0x0, 0x1, 0x1)
        /Users/sshuair/go/pkg/mod/github.com/airbusgeo/[email protected]/godal.go:1283 +0xa2
main.main()
        /Users/sshuair/test/test.go:15 +0x12b
exit status 2

Dear Godal team, Thanks for the great library. I wrote a simple application with it and it runs smoothly on my pc. My overall goal is to run it in a AWS Lambda function, but i have problems to compile it in a way that it is working.

I tried several builds in a docker, but none of them worked. From what I learned, is that I have theoretically two possibities:

• Build a static binary including all relevant c files like explained here https://www.x-cellent.com/posts/cgo-bindings
• Build the application in a Amazon Linux 2 Docker with GDAL installed

My question is, if you maybe have tried it already to run it in AWS Lambda or if you have a running Docker example?

Thanks for your help, Marcel

I wrote a small script to warp a small part of the image, but with godal.Warp it is not working.

The gdal command is:

gdalwarp /vsis3/rastless-tests/TUR_us-newyork_EOMAP_20190309_155148_SENT2_m0010_32bit.tif ./working.tif -t_srs EPSG:3857 -te -8243902 4961937 -8243197 4962527 -ts 256 256

The file is in an public s3 bucket, so testing on your side should work just fine. The produced file has 256 * 256px and is in the New York bay.

I wrote the complementary Golang code with godal:

package main

import "github.com/airbusgeo/godal"

func main() {
	godal.RegisterAll()

	filename := "/vsis3/rastless-tests/TUR_us-newyork_EOMAP_20190309_155148_SENT2_m0010_32bit.tif"
	ds, _ := godal.Open(filename)
	datasets := []*godal.Dataset{ds}

	// gdalwarp /vsis3/rastless-tests/TUR_us-newyork_EOMAP_20190309_155148_SENT2_m0010_32bit.tif ./working.tif -t_srs EPSG:3857 -te -8243902 4961937 -8243197 4962527 -ts 256 256
	options := []string{"-t_srs", "EPSG:3857", "-te", "-8243902", "4961937", "-8243197", "4962527", "-ts", "256", "256"}
	godal.Warp("./not_working.tif", datasets, options)
}

The file seems to be empty and I cannot display it in qgis. I think, that the data is written into the file in a wrong way, as the file size and all metadata are the same like the file which was produced with pure gdal.

It would be great if you could tell if I did a mistake or if it is a godal problem, which you can fix.

Hello Thomas,

I am having issue getting nodata right with WarpInto when different from 0. Below are three attempts to get it right but the read stays desperately at 0. Any idea about what I am doing wrong?

Thanks, Thomas

func TestDatasetWarpInto_NoDataSetAtDst(t *testing.T) {
	os.Setenv("CPL_DEBUG", "ON")
	srs4326, _ := NewSpatialRefFromEPSG(4326)

	srcDS, _ := Create(Memory, "", 1, Byte, 16, 16)
	srcDS.SetSpatialRef(srs4326)
	srcDS.SetGeoTransform([6]float64{45, 1, 0, 35, 0, -1})
	defer srcDS.Close()

	dstDS, _ := Create(Memory, "", 1, Byte, 16, 16)
	dstDS.SetSpatialRef(srs4326)
	dstDS.SetGeoTransform([6]float64{45, 1, 0, 35, 0, -1})
	defer dstDS.Close()

	// set nodata value to src and dst
	for _, b := range srcDS.Bands() {
		b.SetNoData(255)
		assert.Nil(t, b.Fill(255, 0))
	}

	for _, b := range dstDS.Bands() {
		b.SetNoData(255)
	}

	// warp into
	assert.Nil(t, dstDS.WarpInto([]*Dataset{srcDS}, []string{}))

	data := make([]uint8, 1)
	assert.Nil(t, dstDS.Read(0, 0, data, 1, 1))
	assert.Equal(t, uint8(255), data[0])
}

GDAL: GDAL: GDALDriver::Create(MEM,,16,16,1,Byte,(nil))
GDAL: GDAL: GDALDriver::Create(MEM,,16,16,1,Byte,(nil))
GDAL: GDAL: GDAL_CACHEMAX = 786 MB
GDAL: GDALWARP: Defining SKIP_NOSOURCE=YES
GDAL: WARP: Copying metadata from first source to destination dataset
GDAL: GDAL: Computing area of interest: 45, 19, 61, 35
GDAL: OGRCT: Wrap source at 53.
OGRCT: Wrap target at 53.
GDAL: WARP: band=0 dstNoData=255.000000
GDAL: GDAL: GDALWarpKernel()::GWKNearestByte() Src=0,0,16x16 Dst=0,0,16x16
GDAL: GDAL: GDALClose(, this=0x199dfe0)
GDAL: GDAL: GDALClose(, this=0x199d3d0)
--- FAIL: TestDatasetWarpInto_NoDataSetAtDst (0.04s)
    /home/thomascoquet/Work/kayrros-godal/godal/godal_test.go:1863:
        	Error Trace:	godal_test.go:1863
        	Error:      	Not equal:
        	            	expected: 0xff
        	            	actual  : 0x0
        	Test:       	TestDatasetWarpInto_NoDataSetAtDst

func TestDatasetWarpInto_NoDataNoSet(t *testing.T) {
	os.Setenv("CPL_DEBUG", "ON")
	srs4326, _ := NewSpatialRefFromEPSG(4326)

	srcDS, _ := Create(Memory, "", 1, Byte, 16, 16)
	srcDS.SetSpatialRef(srs4326)
	srcDS.SetGeoTransform([6]float64{45, 1, 0, 35, 0, -1})
	defer srcDS.Close()

	dstDS, _ := Create(Memory, "", 1, Byte, 16, 16)
	dstDS.SetSpatialRef(srs4326)
	dstDS.SetGeoTransform([6]float64{45, 1, 0, 35, 0, -1})
	defer dstDS.Close()

	// set nodata value to src and dst
	for _, b := range srcDS.Bands() {
		b.SetNoData(255)
		assert.Nil(t, b.Fill(255, 0))
	}

	// warp into
	assert.Nil(t, dstDS.WarpInto([]*Dataset{srcDS}, []string{}))
	nodata, ok := dstDS.Bands()[0].NoData()
	assert.True(t, ok)
	assert.Equal(t, nodata, float64(255))

	data := make([]uint8, 1)
	assert.Nil(t, dstDS.Read(0, 0, data, 1, 1))
	assert.Equal(t, uint8(255), data[0])
}

GDAL: GDAL: GDALDriver::Create(MEM,,16,16,1,Byte,(nil))
GDAL: GDAL: GDALDriver::Create(MEM,,16,16,1,Byte,(nil))
GDAL: GDAL: GDAL_CACHEMAX = 786 MB
GDAL: GDALWARP: Defining SKIP_NOSOURCE=YES
GDAL: WARP: Copying metadata from first source to destination dataset
GDAL: GDAL: Computing area of interest: 45, 19, 61, 35
GDAL: OGRCT: Wrap source at 53.
OGRCT: Wrap target at 53.
GDAL: WARP: srcNoData=255.000000 dstNoData=255.000000
GDAL: GDAL: GDALWarpKernel()::GWKNearestByte() Src=0,0,16x16 Dst=0,0,16x16
GDAL: GDAL: GDALClose(, this=0x2e3efe0)
GDAL: GDAL: GDALClose(, this=0x2e3e3d0)
--- FAIL: TestDatasetWarpInto_NoDataNoSet (0.03s)
    /home/thomascoquet/Work/kayrros-godal/godal/godal_test.go:1911:
        	Error Trace:	godal_test.go:1911
        	Error:      	Should be true
        	Test:       	TestDatasetWarpInto_NoDataNoSet
    /home/thomascoquet/Work/kayrros-godal/godal/godal_test.go:1912:
        	Error Trace:	godal_test.go:1912
        	Error:      	Not equal:
        	            	expected: 0
        	            	actual  : 255
        	Test:       	TestDatasetWarpInto_NoDataNoSet
    /home/thomascoquet/Work/kayrros-godal/godal/godal_test.go:1916:
        	Error Trace:	godal_test.go:1916
        	Error:      	Not equal:
        	            	expected: 0xff
        	            	actual  : 0x0
        	Test:       	TestDatasetWarpInto_NoDataNoSet

func TestDatasetWarpInto_NoDataWithSwitch(t *testing.T) {
	os.Setenv("CPL_DEBUG", "ON")
	srs4326, _ := NewSpatialRefFromEPSG(4326)

	srcDS, _ := Create(Memory, "", 1, Byte, 16, 16)
	srcDS.SetSpatialRef(srs4326)
	srcDS.SetGeoTransform([6]float64{45, 1, 0, 35, 0, -1})
	defer srcDS.Close()

	dstDS, _ := Create(Memory, "", 1, Byte, 16, 16)
	dstDS.SetSpatialRef(srs4326)
	dstDS.SetGeoTransform([6]float64{45, 1, 0, 35, 0, -1})
	defer dstDS.Close()

	// set nodata value to src and dst
	for _, b := range srcDS.Bands() {
		b.SetNoData(255)
		assert.Nil(t, b.Fill(255, 0))
	}

	// warp into
	assert.Nil(t, dstDS.WarpInto([]*Dataset{srcDS}, []string{"-dstnodata", "255"}))
	data := make([]uint8, 1)
	assert.Nil(t, dstDS.Read(0, 0, data, 1, 1))
	assert.Equal(t, uint8(255), data[0])
}

GDAL: GDAL: GDALDriver::Create(MEM,,16,16,1,Byte,(nil))
GDAL: GDAL: GDALDriver::Create(MEM,,16,16,1,Byte,(nil))
GDAL: GDAL: GDAL_CACHEMAX = 786 MB
GDAL: GDALWARP: Defining SKIP_NOSOURCE=YES
GDAL: WARP: Copying metadata from first source to destination dataset
GDAL: GDAL: Computing area of interest: 45, 19, 61, 35
GDAL: OGRCT: Wrap source at 53.
OGRCT: Wrap target at 53.
GDAL: WARP: dstnodata of band 0 set to 255.000000
GDAL: GDAL: GDALWarpKernel()::GWKNearestByte() Src=0,0,16x16 Dst=0,0,16x16
GDAL: GDAL: GDALClose(, this=0x2e0ffe0)
GDAL: GDAL: GDALClose(, this=0x2e0f3d0)
--- FAIL: TestDatasetWarpInto_NoDataWithSwitch (0.04s)
    /home/thomascoquet/Work/kayrros-godal/godal/godal_test.go:1975:
        	Error Trace:	godal_test.go:1975
        	Error:      	Not equal:
        	            	expected: 0xff
        	            	actual  : 0x0
        	Test:       	TestDatasetWarpInto_NoDataWithSwitch

Bumps github.com/airbusgeo/cogger from 0.0.5 to 0.0.6.

Dependabot will resolve any conflicts with this PR as long as you don't alter it yourself. You can also trigger a rebase manually by commenting @dependabot rebase.

Bumps google.golang.org/api from 0.58.0 to 0.59.0.

Dependabot will resolve any conflicts with this PR as long as you don't alter it yourself. You can also trigger a rebase manually by commenting @dependabot rebase.

Bumps cloud.google.com/go/storage from 1.17.0 to 1.18.2.

Dependabot will resolve any conflicts with this PR as long as you don't alter it yourself. You can also trigger a rebase manually by commenting @dependabot rebase.

Bumps cloud.google.com/go/storage from 1.17.0 to 1.18.1.

Dependabot will resolve any conflicts with this PR as long as you don't alter it yourself. You can also trigger a rebase manually by commenting @dependabot rebase.

Bumps cloud.google.com/go/storage from 1.17.0 to 1.18.0.

Dependabot will resolve any conflicts with this PR as long as you don't alter it yourself. You can also trigger a rebase manually by commenting @dependabot rebase.

I was trying out the godal library (on my M1 Mac) and wrote a simple script as follows:

package main

import (
	"github.com/airbusgeo/godal"
)

func main() {
	godal.RegisterAll()
}

Running go run main.go throws the following error

dyld[19569]: Library not loaded: @rpath/libgdal.30.dylib
  Referenced from: /private/var/folders/y5/yh59dj093xn_dz8lm0mhv6lh0000gp/T/go-build1573968352/b001/exe/test
  Reason: tried: '/usr/local/lib/libgdal.30.dylib' (no such file), '/usr/lib/libgdal.30.dylib' (no such file)
signal: abort trap

godal has a dependency on gdal and I had installed it via conda. Due to this, the dylib is located under my conda folder - /Users/ash/miniconda3/lib not /usr/local/lib.

How can I have the program search for libgdal.dylib in /Users/ash/miniconda3/lib instead of /usr/local/lib ?

Had raised this question in StackOverflow previously but didn't get any solutions to this issue. Link - here

# pkg-config --cflags  -- gdal   
Package 'gdal' has no Name: field
pkg-config: exit status 1

Can you give some examples about the configuration of gdal.pc for windows? thk