--- a/configure	
+++ a/configure	
@@ -3713,6 +3713,8 @@ 
   CFLAGS="$CFLAGS -DMISSING_DLFCN_H"
 fi
+CFLAGS="$CFLAGS -DACCEPT_USE_OF_DEPRECATED_PROJ_API_H=1"
+
  { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether byte ordering is bigendian" >&5
 $as_echo_n "checking whether byte ordering is bigendian... " >&6; }
 if ${ac_cv_c_bigendian+:} false; then :
@@ -4002,10 +4004,10 @@ 
   PROJ_SETTING=missing
 fi
-  for ac_header in projects.h
+  for ac_header in proj_api.h
 do :
-  ac_fn_c_check_header_mongrel "$LINENO" "projects.h" "ac_cv_header_projects_h" "$ac_includes_default"
-if test "x$ac_cv_header_projects_h" = xyes; then :
+  ac_fn_c_check_header_mongrel "$LINENO" "proj_api.h" "ac_cv_header_proj_api_h" "$ac_includes_default"
+if test "x$ac_cv_header_proj_api_h" = xyes; then :
   cat >>confdefs.h <<_ACEOF
 #define HAVE_PROJECTS_H 1
 _ACEOF
@@ -4016,10 +4018,10 @@ 
   if test $PROJ_SETTING = missing ; then
-    as_fn_error $? "Unable to find external PROJ.4 library, give path or use default internal library." "$LINENO" 5
+    as_fn_error $? "Unable to find external PROJ library, give path or use default internal library." "$LINENO" 5
   fi
-  if test "$ac_cv_header_projects_h" = no ; then
-    as_fn_error $? "Unable to find external PROJ.4 projects.h file, give path or use default internal library." "$LINENO" 5
+  if test "$ac_cv_header_proj_api_h" = no ; then
+    as_fn_error $? "Unable to find external PROJ proj_api.h file, give path or use default internal library." "$LINENO" 5
   fi
   PROJ_SETTING=external
@@ -4027,11 +4029,11 @@ 
 elif test "$with_proj" != "no" -a "$with_proj" != "" ; then
-  if test -r $with_proj/include/projects.h ; then
-    echo "checking for $with_proj/include/projects.h ... found"
+  if test -r $with_proj/include/proj_api.h ; then
+    echo "checking for $with_proj/include/proj_api.h ... found"
     PROJ_INCLUDE=-I$with_proj/include
   else
-    as_fn_error $? "Unable to find $with_proj/include/projects.h" "$LINENO" 5
+    as_fn_error $? "Unable to find $with_proj/include/proj_api.h" "$LINENO" 5
   fi
   if test -r $with_proj/lib/libproj.so ; then
--- a/configure.in	
+++ a/configure.in	
@@ -89,13 +89,13 @@ 
 if test "$with_proj" = "yes" ; then
   AC_CHECK_LIB(proj,pj_init,PROJ_SETTING=external,PROJ_SETTING=missing,)
-  AC_CHECK_HEADERS(projects.h)
+  AC_CHECK_HEADERS(proj_api.h)
   if test $PROJ_SETTING = missing ; then
     AC_MSG_ERROR([Unable to find external PROJ.4 library, give path or use default internal library.])
   fi
-  if test "$ac_cv_header_projects_h" = no ; then
-    AC_MSG_ERROR([Unable to find external PROJ.4 projects.h file, give path or use default internal library.])
+  if test "$ac_cv_header_proj_api_h" = no ; then
+    AC_MSG_ERROR([Unable to find external PROJ.4 proj_api.h file, give path or use default internal library.])
   fi
   PROJ_SETTING=external
@@ -103,11 +103,11 @@ 
 elif test "$with_proj" != "no" -a "$with_proj" != "" ; then
-  if test -r $with_proj/include/projects.h ; then
-    echo "checking for $with_proj/include/projects.h ... found"
+  if test -r $with_proj/include/proj_api.h ; then
+    echo "checking for $with_proj/include/proj_api.h ... found"
     PROJ_INCLUDE=-I$with_proj/include
   else
-    AC_MSG_ERROR([Unable to find $with_proj/include/projects.h])
+    AC_MSG_ERROR([Unable to find $with_proj/include/proj_api.h])
   fi
   if test -r $with_proj/lib/libproj.so ; then
--- a/contrib/ogdi_import/ogdi_import.c	
+++ a/contrib/ogdi_import/ogdi_import.c	
@@ -63,12 +63,7 @@ 
 #include "ecs.h"
 #include "shapefil.h"
 #include <assert.h>
-#include "projects.h"
-
-#ifndef PJ_VERSION
-#define projPJ PJ*
-#define projUV UV
-#endif
+#include "proj_api.h"
 static int     ClientID = -1;
 static int      bNoDict = FALSE;
--- a/contrib/ogdi_info/ogdi_info.c	
+++ a/contrib/ogdi_info/ogdi_info.c	
@@ -63,7 +63,7 @@ 
  */
 #include "ecs.h"
-#include "projects.h"
+#include "proj_api.h"
 static int     ClientID = -1;
 static int      bNoDict = FALSE;
@@ -214,7 +214,7 @@ 
 /*                          DumpGlobalRegion()                          */
 /************************************************************************/
-static int DumpGlobalRegion( ecs_Region * region, PJ * proj_defn )
+static int DumpGlobalRegion( ecs_Region * region, projPJ proj_defn )
 {
     ecs_Result *result;
@@ -398,7 +398,7 @@ 
 {
     ecs_Result *result;
-    PJ        *proj_defn = NULL;
+    projPJ            proj_defn = NULL;
 /* -------------------------------------------------------------------- */
 /*      Close old client if there is one active.                        */
--- a/ogdi/c-api/client.c	
+++ a/ogdi/c-api/client.c	
@@ -1579,7 +1579,7 @@ 
   char *error_message;
   ecs_CtlPoints *cpts;
   ecs_Result *res;
-  PJ *tempproj;
+  projPJ tempproj;
   if (multiblock != 0) {
     res = &cln_dummy_result;
@@ -1601,7 +1601,7 @@ 
   /* Check if the projection is valid */
   if (strncmp(projection,PROJ_LONGLAT,13) != 0) {
-    tempproj = (PJ *) cln_ProjInit(projection);
+    tempproj = (projPJ) cln_ProjInit(projection);
     if(tempproj == NULL) {
       res = &cln_dummy_result;
       ecs_SetError(res,1,"This projection string is invalid");
@@ -1778,7 +1778,7 @@ 
   ecs_Result *res;
   register ecs_Client *cln;
   char *server_proj;
-  PJ *oldtarget,*oldsource;
+  projPJ oldtarget,oldsource;
   ecs_Region oldreg;
   int oldisprojequal;
   int oldisTargetLL;
@@ -1877,7 +1877,7 @@ 
   if (strncmp(projection,PROJ_LONGLAT,13) != 0) {
     cln->isTargetLL = FALSE;
-    cln->target = (PJ *) cln_ProjInit(projection);
+    cln->target = (projPJ) cln_ProjInit(projection);
     if(cln->target == NULL) {
       goto setprojerror;
     }
@@ -1923,7 +1923,7 @@ 
   if (strncmp(server_proj,PROJ_LONGLAT,13) != 0) {
     cln->isSourceLL = FALSE;
-    cln->source = (PJ *) cln_ProjInit(server_proj);
+    cln->source = (projPJ) cln_ProjInit(server_proj);
     if(cln->source == NULL) {
       goto setprojerror;
     }
@@ -2331,13 +2331,13 @@ 
  *     char *d: Projection name
  *
  *  OUT
- *     return PJ *: New projection structure. If NULL, the operation
+ *     return projPJ: New projection structure. If NULL, the operation
  *     is a failure.
  *
  *----------------------------------------------------------------------
  */
-PJ *cln_ProjInit(d)
+projPJ cln_ProjInit(d)
      char *d;
 {
   int i,n;
@@ -2345,7 +2345,7 @@ 
   char *l;
   int longueur;
   char *c;
-  PJ *retour;
+  projPJ retour;
   if ((c = (char *) malloc(strlen(d)+3)) == NULL) {
     return NULL;
@@ -2378,7 +2378,7 @@ 
     n++;
   }
-  retour = (PJ *) pj_init(n, (char **) tableau);
+  retour = (projPJ) pj_init(n, (char **) tableau);
   free(c);
   free(tableau);
--- a/ogdi/c-api/ecs_dyna.c	
+++ a/ogdi/c-api/ecs_dyna.c	
@@ -40,7 +40,6 @@ 
 #include <dlfcn.h>
 #endif
-
 /*
    -------------------------------------------------
--- a/ogdi/c-api/ecsgeo.c	
+++ a/ogdi/c-api/ecsgeo.c	
@@ -310,7 +310,7 @@ 
      char *projection;
      double X1,Y1,X2,Y2;
 {
-  PJ *proj;
+  projPJ proj;
   char **argv;
   int argc;
   double lon1,lat1,lon2,lat2;
--- a/ogdi/datum_driver/usa/dtusa.c	
+++ a/ogdi/datum_driver/usa/dtusa.c	
@@ -26,7 +26,12 @@ 
   ********************************************************************/
 #include "ecs.h"
-#include "projects.h"
+#include "proj_api.h"
+
+/* Definition from Proj.4 */
+projUV nad_cvt(projUV, int, struct CTABLE *);
+struct CTABLE *nad_init(projCtx ctx, char *);
+void nad_free(struct CTABLE *);
 typedef struct {
   struct CTABLE *dtptr;
--- a/ogdi/include/ecs_util.h	
+++ a/ogdi/include/ecs_util.h	
@@ -129,12 +129,7 @@ 
 #include <sys/types.h>
 #include <sys/stat.h>
-#include "projects.h"
-
-/* Ensure we are compatible with PROJ.4.4.x and PROJ.4.3.x */
-#ifndef USE_PROJUV
-#  define projUV UV
-#endif
+#include "proj_api.h"
 #include "ecs.h"
@@ -1093,8 +1088,8 @@ 
      ecs_Family currentSelectionFamily: Current layer selection type
      char *tclprocname: attribute callback procedure for tcl
      char *target_proj: Projection descriptor
-     PJ *target: target (c interface) projection descriptors
-     PJ *source: source (driver) projection descriptors
+     projPJ target: target (c interface) projection descriptors
+     projPJ source: source (driver) projection descriptors
      ecs_Datum targetdatum: target datum information
      ecs_Datum sourcedatum: source datum information
      void *dthandle: Handle to the datum driver
@@ -1131,8 +1126,8 @@ 
   ecs_Family currentSelectionFamily; /* Current layer selection type */
   char *tclprocname;      /* attribute callback procedure for tcl */
   char *target_proj;
-  PJ *target;             /* source and target projection descriptors */
-  PJ *source;
+  projPJ target;             /* source and target projection descriptors */
+  projPJ source;
   int isSourceLL;         /* flags to avoid unnecessary computation */
   int isTargetLL;
   int isProjEqual;
@@ -1204,7 +1199,7 @@ 
 /* Projection conversion functions */
-PJ *cln_ProjInit                     _ANSI_ARGS_((char *d));
+projPJ cln_ProjInit                     _ANSI_ARGS_((char *d));
 int cln_CompareProjections           _ANSI_ARGS_((int ClientID));
 int cln_UpdateMaxRegion              _ANSI_ARGS_((int ClientID, double x, double y, ecs_Region *gr, int sens, int first));
 int cln_ConvRegion                   _ANSI_ARGS_((int ClientID, ecs_Region *gr, int sens));