int main(int argc, char **argv) {
PJ_INFO projInfo = proj_info();
std::cerr << "proj release: " << projInfo.release << std::endl;
double xMin = 0.;
// Get UTM zone of grid's W edge
int utmZone = ((xMin + 180)/6 + 0.5);
std::cerr << "UTM zone: " << utmZone << std::endl;
PJ_CONTEXT *projContext = proj_context_create();
if (projContext) {
std::cerr << "Created projContext OK" << std::endl;
} else {
return -1;
}
const char *srcCRS = "EPSG:4326";
char targCRS[64];
sprintf(targCRS, "+proj=utm +zone=%d +datum=WGS84", utmZone);
std::cout << "targCRS: " << targCRS << std::endl;
PJ *proj = proj_create_crs_to_crs (projContext,
srcCRS,
targCRS,
nullptr);
if (!proj) {
std::cerr << "failed to create proj" << std::endl;
} else {
std::cerr << "created proj OK" << std::endl;
}
return 0;
}
```
With VTK PROJ **not** enabled, the program works, gives this output:
```auto
proj release: Rel. 7.1.0, August 1st, 2020
UTM zone: 30
Created projContext OK
targCRS: +proj=utm +zone=30 +datum=WGS84
created proj OK
```
When VTK PROJ **is** enabled, the proj\_create\_crs\_to\_crs() call fails:
```auto
proj release: Rel. 8.1.0, July 1st, 2021
UTM zone: 30
Created projContext OK
targCRS: +proj=utm +zone=30 +datum=WGS84
libproj_proj_create: Cannot find proj.db
failed to create proj
```
The VTK PROJ proj.db is at /usr/local/share/vtk-9.2/proj/proj.db, so I tried setting environment variable PROJ\_LIB to /usr/local/share/vtk-9.2/proj/ - but get the same “Cannot find proj.db” error. Does anyone know why this is happening?
Thanks!
---
### Author:  [@Tomasso](https://discourse.vtk.org/u/Tomasso)
#### Post date: [October 5, 2022, 7:38pm UTC](https://discourse.vtk.org/t/vtk-proj-simple-example-not-working/9532/2 "2022-10-05T19:38:05Z")
I set PROJ\_DEBUG=3, and get a bit more detail on this error:
```auto
proj release: Rel. 8.1.0, July 1st, 2021
UTM zone: 30
Created projContext OK
pj_open_lib(proj.db): call fopen(proj.db) - failed
libproj_proj_create: Cannot find proj.db
pj_open_lib(proj.db): call fopen(proj.db) - failed
libproj_proj_create: no database context specified
Cannot instantiate source_crs
```
Based on those debug messages it appears PROJ is looking for proj.db in the current working directory. I place a copy of proj.db in the current working directory, and now the program works. But of course it’s not practical to put a copy of proj.db in every directory the program is run from. Why is it looking in the current directory by default? And why doesn’t setting PROJ\_LIB make any difference?
---
### Author:  [@danlipsa](https://discourse.vtk.org/u/danlipsa)
#### Post date: [October 5, 2022, 8:17pm UTC](https://discourse.vtk.org/t/vtk-proj-simple-example-not-working/9532/3 "2022-10-05T20:17:37Z")
Are you trying to use proj in a program using VTK? If that is the case, you can investigate further by turning on VTK\_MODULE\_ENABLE\_VTK\_IOCesium3DTiles. This module has a writer that uses proj. You can try to run the test for this writer to see if it works and also see how proj is used in this writer.
I think we test running the tests against installed VTK so that should pick up proj.db correctly as well.
---
### Author:  [@Tomasso](https://discourse.vtk.org/u/Tomasso)
#### Post date: [October 5, 2022, 9:25pm UTC](https://discourse.vtk.org/t/vtk-proj-simple-example-not-working/9532/4 "2022-10-05T21:25:18Z")
Yes, my VTK application calls PROG functions. I submitted a description of this odd behavior to the PROJ email list, and a response claims that PROJ-8.1.0 does in fact add $PROJ\_LIB to the searchpath, contrary to what I see with the PROJ-8.1.0 shipped with VTK-9.2.0.
Is there some way I can easily disable VTK’s use of its “internal” PROJ code, i.e. so that my VTK application invokes the “external” PROG headers/libraries already installed on my system?
Thanks!
---
### Author:  [@danlipsa](https://discourse.vtk.org/u/danlipsa)
#### Post date: [October 5, 2022, 9:34pm UTC](https://discourse.vtk.org/t/vtk-proj-simple-example-not-working/9532/5 "2022-10-05T21:34:38Z")
VTK\_MODULE\_USE\_EXTERNAL\_VTK\_libproj ON.
Dan
---
### Author:  [@Tomasso](https://discourse.vtk.org/u/Tomasso)
#### Post date: [October 5, 2022, 10:02pm UTC](https://discourse.vtk.org/t/vtk-proj-simple-example-not-working/9532/6 "2022-10-05T22:02:31Z")
Sorry Dan, how do I use that flag? When compiling VTK, or when compiling my app?
Thanks!
---
### Author:  [@danlipsa](https://discourse.vtk.org/u/danlipsa)
#### Post date: [October 6, 2022, 1:12am UTC](https://discourse.vtk.org/t/vtk-proj-simple-example-not-working/9532/7 "2022-10-06T01:12:03Z")
In cmake-gui when you compile VTK.