func transform(srcpj, dstpj *Proj, x, y, z []float64) ([]float64, []float64, []float64, error)

always allocates the result []float64. this can be improved with

func transform(srcpj, dstpj *Proj, x, y, z []float64, u, v, w []float64) (error)

When running Transform in goroutines, it will intermittently panic:

e = C.transform(srcpj.pj, dstpj.pj, C.long(ln), &x1[0], &y1[0], nil)

Here's the panic:

fatal error: unexpected signal during runtime execution

goroutine 12 [syscall, locked to thread]:
runtime.cgocall_errno(0x40047c0, 0xc2080e9788, 0xc200000000)
    /usr/local/go/src/runtime/cgocall.go:130 +0xf5 fp=0xc2080e9768 sp=0xc2080e9740
github.com/pebbe/go-proj-4/proj._Cfunc_transform(0x9300100, 0x9300540, 0x1, 0xc2081c0650, 0xc2081c0658, 0x0, 0x0)
    github.com/pebbe/go-proj-4/proj/_obj/_cgo_gotypes.go:79 +0x44 fp=0xc2080e9788 sp=0xc2080e9768
github.com/pebbe/go-proj-4/proj.transform(0xc20802c970, 0xc20802c990, 0xc2080e99a8, 0x1, 0x1, 0xc2080e99a0, 0x1, 0x1, 0x0, 0x0, ...)
    /Users/Shared/Development/git.urban4m.com/projects/AP/app-tiler/src/github.com/pebbe/go-proj-4/proj/proj.go:114 +0xac1 fp=0xc2080e98e8 sp=0xc2080e9788
github.com/pebbe/go-proj-4/proj.Transform2(0xc20802c970, 0xc20802c990, 0xbff4fc1f999beca7, 0x3fe74af9b8a9018a, 0x2, 0x2, 0x0, 0x0)
    /Users/Shared/Development/git.urban4m.com/projects/AP/app-tiler/src/github.com/pebbe/go-proj-4/proj/proj.go:138 +0x157 fp=0xc2080e9a28 sp=0xc2080e98e8

hi,

Following readme go get v5 fails:

go get github.com/pebbe/go-proj-4/proj/v5: module github.com/pebbe/go-proj-4@upgrade found (v0.9.2), but does not contain package github.com/pebbe/go-proj-4/proj/v5

the other repo works: go get github.com/pebbe/proj/v5

I am using homebrew on my mac to maintain a few packages like proj-4 which installs all headers and libraries in /usr/local/{include,lib}. If I change the cgo directive to use pkg-config it will pick the location of the header files and libraries properly.

diff --git a/proj/proj.go b/proj/proj.go index e451626..917383c 100644 --- a/proj/proj.go +++ b/proj/proj.go @@ -26,7 +26,7 @@ Example usage: package proj

/* -#cgo LDFLAGS: -lproj +#cgo pkg-config: proj #include "proj.h" */ import "C"

package main

import (
    "fmt"

    "github.com/pebbe/go-proj-4/proj"
)

func main() {
    if merc, err := proj.NewProj("+proj=merc +ellps=clrk66 +lat_ts=33"); err != nil {
        fmt.Printf(
            "error getting mercator *proj.Proj: %s\n",
            err)
    } else if ll, err := proj.NewProj("+proj=latlong"); err != nil {
        fmt.Printf(
            "error getting ll *proj.Proj: %s\n",
            err)
    } else {
        long, lat := 90.0, -66.51326044311185
        if x, y, err := proj.Transform2(
            ll,
            merc,
            proj.DegToRad(lat),
            proj.DegToRad(long),
        ); err != nil {
            fmt.Printf(
                "error making mercator projection: %s\n",
                err)
        } else {
            fmt.Printf(
                "success: (%f, %f)", x, y)
        }

    }
}

// Local Variables:
// compile-cmd: "go run proj_transform2_bug.go"
// End:

in a go module project, just upgraded to go1.12 today and compile fails with

../../go/pkg/mod/github.com/pebbe/[email protected]/proj/proj.go:48:9: identifier "_Ctype_projPJ" may conflict with identifiers generated by cgo

go-proj-4 [e.g., tests] work fine for proj.4 4.8.0 [circa march 2012] but fail for 4.9.1 [circa march 2015]. is go-proj-4 tracking proj releases? if yes, then this may be an unrelated os/userland proj packaging issue instead. if no, then see below.

workaround unknown. notes follow: os: archlinux. using packaged proj. (4.8.0 works fine). have not tried installing proj 4.9.1 directly from source.

$ go get -u github.com/pebbe/go-proj-4/proj $ cd github.com/pebbe/go-proj-4/proj $ proj Rel. 4.9.1, 04 March 2015 usage: proj [ -beEfiIlormsStTvVwW [args] ] [ +opts[=arg] ] [ files ] $ go test --- FAIL: TestMercToLatlong (0.00s) proj_test.go:18: major axis or radius = 0 or not given proj_test.go:23: projection is closed --- FAIL: TestInvalidErrorProblem (0.00s) proj_test.go:43: major axis or radius = 0 or not given FAIL exit status 1 FAIL github.com/pebbe/go-proj-4/proj 0.037s

ls -l proj*

-rw-r--r-- 1 root root 3156060 Dec 28 2013 proj-4.8.0-3-armv7h.pkg.tar.xz -rw-r--r-- 1 root root 3222600 Mar 13 10:25 proj-4.9.1-1-armv7h.pkg.tar.xz

[downgrading package proj (4.9.1-1 => 4.8.0-3)] $ proj Rel. 4.8.0, 6 March 2012 usage: proj [ -beEfiIlormsStTvVwW [args] ] [ +opts[=arg] ] [ files ] $ go test PASS

ok github.com/pebbe/go-proj-4/proj 0.032s

reviewing https://trac.osgeo.org/proj/ https://svn.osgeo.org/metacrs/proj/trunk/proj/NEWS does not mention any 4.8 -> 4.9 incompatible changes?

perhaps go-proj could expose [or at least test] pj_get_release() to clarify tracking / compatibility / issues with upstream proj-4. https://svn.osgeo.org/metacrs/proj/trunk/proj/src/pj_release.c: char const pj_release[]="Rel. 4.9.1, 04 March 2015";

package main

import (
    "fmt"

    "github.com/pebbe/go-proj-4/proj"
)

func main() {
    projs := []string{
        "+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null +wktext  +no_defs",
        "+proj=merc +ellps=clrk66 +lat_ts=33",
        "+init=EPSG:4326",
        "+init=EPSG:3857",
    }
    for _, def := range projs {
        NewProjMust(def)
    }
    // the EPSG projections fail to compile
}
func NewProjMust(spec string) *proj.Proj {
    if p, err := proj.NewProj(spec); err != nil {
        fmt.Printf("error creating projection from '%s': %s\n", spec, err.Error())
        return nil
    } else {
        return p
    }
}

// Local Variables:
// compile-cmd: "go run proj_panic.go"
// End:

Result: the EPSG projections fail to compile

go get github.com/pebbe/go-proj-4/proj

# github.com/pebbe/go-proj-4/proj
In file included from ../../../../github.com/pebbe/go-proj-4/proj/proj.go:30:
./proj.h:1:10: fatal error: 'proj_api.h' file not found
#include <proj_api.h>
         ^
1 error generated.

This is to avoid the following error:

/usr/include/proj_api.h:37:2: error: #error 'To use the proj_api.h you must define the macro ACCEPT_USE_OF_DEPRECATED_PROJ_API_H'

This is necessary when using proj version 6.0.0 onwards. See release notes here.

An error was reported during this installation. What are the environment required for this installation project? # github.com/pebbe/go-proj-4/proj In file included from ..\..\github.com\pebbe\go-proj-4\proj\proj.go:33: ./proj.h:2:10: fatal error: proj_api.h: No such file or directory #include <proj_api.h> ^~~~~~~~~~~~ compilation terminated.