diff --git a/.gitignore b/.gitignore
index 2dc827ccf..c9d3f6e12 100644
--- a/.gitignore
+++ b/.gitignore
@@ -9,8 +9,8 @@
 # USE CAUTION WHEN ADDING WILDCARDS, as some builds use different filename   #
 # conventions than others                                                    #
 ##############################################################################
-build/
-install/
+build*/
+install*/
 
 *.[aox]
 *.mod
diff --git a/.gitmodules b/.gitmodules
index 2c09fa095..742a824df 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,4 +1,4 @@
-[submodule "sorc/post_gtg.fd"]
-	path = sorc/post_gtg.fd
-	url = https://github.com/NCAR/UPP_GTG
-        update = none
+[submodule "post_gtg.fd"]
+  path = sorc/ncep_post.fd/post_gtg.fd
+  url = https://github.com/NCAR/UPP_GTG
+  update = none
diff --git a/CMakeLists.txt b/CMakeLists.txt
index ff311e9d0..8100dd0d2 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -15,6 +15,7 @@ list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake")
 option(OPENMP "use OpenMP threading" ON)
 option(BUILD_POSTEXEC "Build NCEPpost executable" ON)
 option(BUILD_WITH_WRFIO "Build NCEPpost with WRF-IO library" OFF)
+option(BUILD_WITH_GTG   "Build NCEPpost with NCAR/GTG" OFF)
 option(ENABLE_DOCS "Enable generation of doxygen-based documentation." OFF)
 
 if(NOT CMAKE_BUILD_TYPE MATCHES "^(Debug|Release|RelWithDebInfo|MinSizeRel)$")
@@ -47,7 +48,9 @@ find_package(bacio REQUIRED)
 find_package(crtm REQUIRED)
 find_package(g2 REQUIRED)
 find_package(g2tmpl REQUIRED)
-find_package(ip REQUIRED)
+if(BUILD_WITH_GTG)
+  find_package(ip REQUIRED)
+endif()
 
 if(BUILD_POSTEXEC)
   find_package(nemsio REQUIRED)
diff --git a/sorc/ncep_post.fd/CMakeLists.txt b/sorc/ncep_post.fd/CMakeLists.txt
index 8dc6fae37..5fba419fc 100644
--- a/sorc/ncep_post.fd/CMakeLists.txt
+++ b/sorc/ncep_post.fd/CMakeLists.txt
@@ -63,20 +63,12 @@ list(APPEND LIB_SRC
     GPVS.f
     grib2_module.f
     GRIDSPEC.f
-    gtg_algo.F90
-    gtg_compute.F90
-    gtg_config.F90
-    gtg_ctlblk.F90
-    gtg_filter.F90
-    gtg_indices.F90
-    gtg_smoothseams.F90
     ICAOHEIGHT.f
     kinds_mod.F
     LFMFLD.f
     LFMFLD_GFS.f
     LOOKUP.f
     machine.f
-    map_routines.F90
     MAPSSLP.f
     MASKS_mod.f
     MDL2AGL.f
@@ -137,6 +129,22 @@ list(APPEND LIB_SRC
     xml_perl_data.f
     ZENSUN.f)
 
+list(APPEND GTG_LIB_SRC
+  gtg_algo.F90
+  gtg_compute.F90
+  gtg_config.F90
+  gtg_ctlblk.F90
+  gtg_filter.F90
+  gtg_indices.F90
+  gtg_smoothseams.F90
+  map_routines.F90)
+
+if(BUILD_WITH_GTG)
+  list(TRANSFORM GTG_LIB_SRC PREPEND post_gtg.fd/)
+endif()
+
+list(APPEND LIB_SRC ${GTG_LIB_SRC})
+
 list(APPEND EXE_SRC
     ASSIGNNEMSIOVAR.f
     GETNEMSNDSCATTER.f
@@ -200,10 +208,14 @@ target_link_libraries(${LIBNAME} PUBLIC
   crtm::crtm
   g2::g2_4
   g2tmpl::g2tmpl
-  ip::ip_4
   MPI::MPI_Fortran
   NetCDF::NetCDF_Fortran)
 
+if(BUILD_WITH_GTG)
+  target_link_libraries(${LIBNAME} PUBLIC
+  ip::ip_4)
+endif()
+
 if(OpenMP_Fortran_FOUND)
   target_link_libraries(${LIBNAME} PUBLIC OpenMP::OpenMP_Fortran)
 endif()
diff --git a/sorc/post_gtg.fd b/sorc/ncep_post.fd/post_gtg.fd
similarity index 100%
rename from sorc/post_gtg.fd
rename to sorc/ncep_post.fd/post_gtg.fd