Char issues with no_data

[r-barnes]

Extracted from #17 by @joeperdefloep

I don't think it is related to the issue, but I also had some overflow warnings when building the program related to the nodata value.

Details

Scanning dependencies of target arc_raster_rescue
make[2]: Warning: File 'CMakeFiles/arc_raster_rescue.dir/depend.make' has modification time 0.71 s in the future
[ 25%] Building CXX object CMakeFiles/arc_raster_rescue.dir/src/arr.cpp.o
/mnt/c/Users/Joep/Documents/ArcRasterRescue/src/arr.cpp: In instantiation of ‘RasterData::RasterData(std::string, const RasterBase&) [with T = unsigned char; std::string = std::__cxx11::basic_string]’:
/mnt/c/Users/Joep/Documents/ArcRasterRescue/src/arr.cpp:1246:20: required from ‘void ExportTypedRasterToGeoTIFF(std::string, std::string, int, std::string) [with T = unsigned char; std::string = std::__cxx11::basic_string]’
/mnt/c/Users/Joep/Documents/ArcRasterRescue/src/arr.cpp:1278:84: required from here
/mnt/c/Users/Joep/Documents/ArcRasterRescue/src/arr.cpp:958:36: warning: unsigned conversion from ‘int’ to ‘unsigned char’ changes value from ‘-9999’ to ‘241’ [-Woverflow]
958 | resize(maxpx-minpx, maxpy-minpy, -9999);
| ^~~~~
/mnt/c/Users/Joep/Documents/ArcRasterRescue/src/arr.cpp:1132:13: warning: unsigned conversion from ‘int’ to ‘unsigned char’ changes value from ‘-9999’ to ‘241’ [-Woverflow]
1132 | no_data = -9999; //TODO: This cannot always be NoData.
| ^~~~~
/mnt/c/Users/Joep/Documents/ArcRasterRescue/src/arr.cpp: In instantiation of ‘RasterData::RasterData(std::string, const RasterBase&) [with T = signed char; std::string = std::__cxx11::basic_string]’:
/mnt/c/Users/Joep/Documents/ArcRasterRescue/src/arr.cpp:1246:20: required from ‘void ExportTypedRasterToGeoTIFF(std::string, std::string, int, std::string) [with T = signed char; std::string = std::__cxx11::basic_string]’
/mnt/c/Users/Joep/Documents/ArcRasterRescue/src/arr.cpp:1284:83: required from here
/mnt/c/Users/Joep/Documents/ArcRasterRescue/src/arr.cpp:958:36: warning: overflow in conversion from ‘int’ to ‘signed char’ changes value from ‘-9999’ to ‘-15’ [-Woverflow]
958 | resize(maxpx-minpx, maxpy-minpy, -9999);
| ^~~~~
/mnt/c/Users/Joep/Documents/ArcRasterRescue/src/arr.cpp:1132:13: warning: overflow in conversion from ‘int’ to ‘signed char’ changes value from ‘-9999’ to ‘-15’ [-Woverflow]
1132 | no_data = -9999; //TODO: This cannot always be NoData.
| ^~~~~
[ 50%] Linking CXX static library libarc_raster_rescue.a
make[2]: warning: Clock skew detected. Your build may be incomplete.
[ 50%] Built target arc_raster_rescue
Scanning dependencies of target arc_raster_rescue.exe
make[2]: Warning: File 'CMakeFiles/arc_raster_rescue.exe.dir/depend.make' has modification time 0.7 s in the future
[ 75%] Building CXX object CMakeFiles/arc_raster_rescue.exe.dir/evaluation/main.cpp.o
[100%] Linking CXX executable arc_raster_rescue.exe
make[2]: warning: Clock skew detected. Your build may be incomplete.
[100%] Built target arc_raster_rescue.exe