libgis: G_get_projepsg() and G_database_epsg_code()

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@60123 15284696-431f-4ddb-bdfa-cd5b030d7da7

include/defs/gis.h

@@ -287,6 +287,7 @@ int G_read_ellipsoid_table(int);
 /* get_projinfo.c */
 struct Key_Value *G_get_projunits(void);
 struct Key_Value *G_get_projinfo(void);
+struct Key_Value *G_get_projepsg(void);
 
 /* get_window.c */
 void G_get_window(struct Cell_head *);
@@ -552,6 +553,7 @@ const char *G_database_projection_name(void);
 const char *G_database_datum_name(void);
 const char *G_database_ellipse_name(void);
 double G_database_units_to_meters_factor(void);
+const char *G_database_epsg_code(void);
 
 /* put_window.c */
 int G_put_window(const struct Cell_head *);

include/gis.h

@@ -95,6 +95,7 @@ static const char *GRASS_copyright __attribute__ ((unused))
 
 #define PROJECTION_FILE "PROJ_INFO"
 #define UNIT_FILE       "PROJ_UNITS"
+#define EPSG_FILE       "PROJ_EPSG"
 
 #ifdef __MINGW32__
 #define CONFIG_DIR "GRASS7"

lib/gis/get_projinfo.c

@@ -3,7 +3,7 @@
   
   \brief GIS Library - Get projection info
   
-  (C) 1999-2008, 2011 by the GRASS Development Team
+  (C) 1999-2014 by the GRASS Development Team
   
   This program is free software under the GNU General Public License
   (>=v2). Read the file COPYING that comes with GRASS for details.
@@ -21,7 +21,10 @@
   Note: Allocated Key_Value structure should be freed by
   G_free_key_value().
   
+  Prints a warning if no units information available.
+
   \return pointer to Key_Value structure with key/value pairs
+  \return NULL on failure
 */
 struct Key_Value *G_get_projunits(void)
 {
@@ -47,7 +50,10 @@ struct Key_Value *G_get_projunits(void)
   Note: Allocated Key_Value structure should be freed by
   G_free_key_value().
   
+  Prints a warning if no projection information available.
+
   \return pointer to Key_Value structure with key/value pairs
+  \return NULL on failure
 */
 struct Key_Value *G_get_projinfo(void)
 {
@@ -66,3 +72,30 @@ struct Key_Value *G_get_projinfo(void)
 
     return in_proj_keys;
 }
+
+/*!
+  \brief Gets EPSG information for the current location
+  
+  Note: Allocated Key_Value structure should be freed by
+  G_free_key_value().
+  
+  \return pointer to Key_Value structure with key/value pairs
+  \return NULL when EPSG code is defined for location
+*/
+struct Key_Value *G_get_projepsg(void)
+{
+    struct Key_Value *in_epsg_keys;
+    char path[GPATH_MAX];
+
+    G_file_name(path, "", EPSG_FILE, PERMANENT);
+    if (access(path, 0) != 0) {
+	if (G_projection() != PROJECTION_XY) {
+            G_debug(1, "<%s> file not found for location <%s>",
+                    EPSG_FILE, G_location());
+	}
+	return NULL;
+    }
+    in_epsg_keys = G_read_key_value_file(path);
+
+    return in_epsg_keys;
+}

lib/gis/proj3.c

@@ -1,9 +1,9 @@
 /*!
-  \file gis/proj3.c
+  \file lib/gis/proj3.c
 
   \brief GIS Library - Projection support (database)
   
-  (C) 2001-2010 by the GRASS Development Team
+  (C) 2001-2014 by the GRASS Development Team
   
   This program is free software under the GNU General Public License
   (>=v2). Read the file COPYING that comes with GRASS for details.
@@ -17,11 +17,12 @@
 
 static const char *lookup_proj(const char *);
 static const char *lookup_units(const char *);
+static const char *lookup_epsg();
 static int equal(const char *, const char *);
 static int lower(char);
 
 static int initialized;
-static struct Key_Value *proj_info, *proj_units;
+static struct Key_Value *proj_info, *proj_units, *proj_epsg;
 
 static void init(void)
 {
@@ -30,12 +31,13 @@ static void init(void)
 
     proj_info = G_get_projinfo();
     proj_units = G_get_projunits();
+    proj_epsg = G_get_projepsg();
 
     G_initialize_done(&initialized);
 }
 
 /*!
-  \brief Get database units (localized) name
+  \brief Get units (localized) name for the current location
   
   Returns a string describing the database grid units. It returns a
   plural form (eg. 'feet') if <i>plural</i> is non-zero. Otherwise it
@@ -81,7 +83,7 @@ const char *G_database_unit_name(int plural)
 }
 
 /*!
-  \brief Query cartographic projection
+  \brief Query cartographic projection for the current location
   
   Returns a pointer to a string which is a printable name for
   projection code <i>proj</i> (as returned by G_projection). Returns
@@ -153,7 +155,7 @@ double G_database_units_to_meters_factor(void)
 }
 
 /*!
-  \brief Get datum name for database
+  \brief Get datum name for the current location
   
   Returns a pointer to the name of the map datum of the current
   database. If there is no map datum explicitely associated with the
@@ -183,7 +185,7 @@ const char *G_database_datum_name(void)
 }
 
 /*!
-  \brief Get ellipsoid name of current database
+  \brief Get ellipsoid name for the current location
   
   \return pointer to valid name if ok
   \return NULL on error
@@ -206,19 +208,36 @@ const char *G_database_ellipse_name(void)
     return name;
 }
 
-static const char *lookup_proj(const char *key)
+/*!
+  \brief Get EPGS code for the current location
+  
+  \return pointer to valid EPSG code on success
+  \return NULL on error
+*/
+const char *G_database_epsg_code(void)
+{
+    return lookup_epsg();
+}
+
+const char *lookup_proj(const char *key)
 {
     init();
     return G_find_key_value(key, proj_info);
 }
 
-static const char *lookup_units(const char *key)
+const char *lookup_units(const char *key)
 {
     init();
     return G_find_key_value(key, proj_units);
 }
 
-static int equal(const char *a, const char *b)
+const char *lookup_epsg()
+{
+    init();
+    return G_find_key_value("epsg", proj_epsg);
+}
+
+int equal(const char *a, const char *b)
 {
     if (a == NULL || b == NULL)
 	return a == b;
@@ -230,7 +249,7 @@ static int equal(const char *a, const char *b)
     return 1;
 }
 
-static int lower(char c)
+int lower(char c)
 {
     if (c >= 'A' && c <= 'Z')
 	c += 'a' - 'A';