Merge bf3c8c9 into e65df1f

docs/source/operations/projections/index.rst

@@ -43,7 +43,6 @@ Projections map the spherical 3D space to a flat 2D space.
    eqdc
    eqearth
    euler
-   etmerc
    fahey
    fouc
    fouc_s

docs/source/operations/projections/tmerc.rst

@@ -14,7 +14,7 @@ The transverse Mercator projection in its various forms is the most widely used
 | **Defined area**    | Global, but reasonably accurate only within 15 degrees   |
 |                     | of the central meridian                                  |
 +---------------------+----------------------------------------------------------+
-| **Alias**           | tmerc                                                    |
+| **Alias**           | tmerc, etmerc                                            |
 +---------------------+----------------------------------------------------------+
 | **Domain**          | 2D                                                       |
 +---------------------+----------------------------------------------------------+
@@ -68,13 +68,19 @@ Example using Gauss-Kruger on Germany area (aka EPSG:31467) ::
 Example using Gauss Boaga on Italy area (EPSG:3004) ::
 
     $ echo 15 42 | proj +proj=tmerc +lat_0=0 +lon_0=15 +k_0=0.9996 +x_0=2520000 +y_0=0 +ellps=intl +units=m +no_defs
-    2520000.00	4649858.60 
+    2520000.00	4649858.60
 
 Parameters
 ################################################################################
 
 .. note:: All parameters for the projection are optional.
 
+.. option:: +approx
+
+    .. versionadded:: 6.0.0
+
+    Use faster, less accurate algorithm for the Transverse Mercator.
+
 .. include:: ../options/lon_0.rst
 
 .. include:: ../options/lat_0.rst

docs/source/operations/projections/utm.rst

@@ -66,6 +66,12 @@ Required
 
     Add this flag when using the UTM on the southern hemisphere.
 
+.. option:: +approx
+
+    .. versionadded:: 6.0.0
+
+    Use faster, less accurate algorithm for the Transverse Mercator.
+
 Optional
 -------------------------------------------------------------------------------
 

include/proj/io.hpp

@@ -365,7 +365,7 @@ class PROJ_GCC_DLL PROJStringFormatter {
     PROJ_DLL ~PROJStringFormatter();
     //! @endcond
 
-    PROJ_DLL void setUseETMercForTMerc(bool flag);
+    PROJ_DLL void setUseApproxTMerc(bool flag);
 
     PROJ_DLL const std::string &toString() const;
 
@@ -378,7 +378,7 @@ class PROJ_GCC_DLL PROJStringFormatter {
     PROJ_DLL void startInversion();
     PROJ_DLL void stopInversion();
     PROJ_INTERNAL bool isInverted() const;
-    PROJ_INTERNAL bool getUseETMercForTMerc(bool &settingSetOut) const;
+    PROJ_INTERNAL bool getUseApproxTMerc() const;
     PROJ_INTERNAL void setCoordinateOperationOptimizations(bool enable);
 
     PROJ_DLL void

src/Makefile.am

@@ -122,7 +122,6 @@ libproj_la_SOURCES = \
 	projections/wag7.cpp \
 	projections/lcca.cpp \
 	projections/geos.cpp \
-	projections/etmerc.cpp \
 	projections/boggs.cpp \
 	projections/collg.cpp \
 	projections/comill.cpp \

src/iso19111/c_api.cpp

@@ -1205,9 +1205,8 @@ const char *proj_as_wkt(PJ_CONTEXT *ctx, const PJ *obj, PJ_WKT_TYPE type,
  * @param type PROJ String version.
  * @param options NULL-terminated list of strings with "KEY=VALUE" format. or
  * NULL.
- * The currently recognized option is USE_ETMERC=YES to use
- * +proj=etmerc instead of +proj=tmerc (or USE_ETMERC=NO to disable implicit
- * use of etmerc by utm conversions)
+ * The currently recognized option is USE_APPROX_TMERC=YES to add the +approx
+ * flag to +proj=tmerc or +proj=utm
  * @return a string, or NULL in case of error.
  */
 const char *proj_as_proj_string(PJ_CONTEXT *ctx, const PJ *obj,
@@ -1241,10 +1240,8 @@ const char *proj_as_proj_string(PJ_CONTEXT *ctx, const PJ *obj,
     try {
         auto formatter = PROJStringFormatter::create(convention, dbContext);
         if (options != nullptr && options[0] != nullptr) {
-            if (ci_equal(options[0], "USE_ETMERC=YES")) {
-                formatter->setUseETMercForTMerc(true);
-            } else if (ci_equal(options[0], "USE_ETMERC=NO")) {
-                formatter->setUseETMercForTMerc(false);
+            if (ci_equal(options[0], "USE_APPROX_TMERC=YES")) {
+                formatter->setUseApproxTMerc(true);
             }
         }
         obj->lastPROJString = exportable->exportToPROJString(formatter.get());

src/iso19111/coordinateoperation.cpp

@@ -5381,13 +5381,11 @@ bool Conversion::addWKTExtensionNode(io::WKTFormatter *formatter) const {
         const auto &l_method = method();
         const auto &methodName = l_method->nameStr();
         const int methodEPSGCode = l_method->getEPSGCode();
-        int zone = 0;
-        bool north = true;
-        if (l_method->getPrivate()->projMethodOverride_ == "etmerc" &&
-            !isUTM(zone, north)) {
+        if (l_method->getPrivate()->projMethodOverride_ == "tmerc approx" ||
+            l_method->getPrivate()->projMethodOverride_ == "utm approx") {
             auto projFormatter = io::PROJStringFormatter::create();
             projFormatter->setCRSExport(true);
-            projFormatter->setUseETMercForTMerc(true);
+            projFormatter->setUseApproxTMerc(true);
             formatter->startNode(io::WKTConstants::EXTENSION, false);
             formatter->addQuotedString("PROJ4");
             _exportToPROJString(projFormatter.get());
@@ -5479,17 +5477,21 @@ void Conversion::_exportToPROJString(
     const auto &convName = nameStr();
     bool bConversionDone = false;
     bool bEllipsoidParametersDone = false;
-    bool useETMerc = false;
+    bool useApprox = false;
     if (methodEPSGCode == EPSG_CODE_METHOD_TRANSVERSE_MERCATOR) {
         // Check for UTM
         int zone = 0;
         bool north = true;
-        bool etMercSettingSet = false;
-        useETMerc = formatter->getUseETMercForTMerc(etMercSettingSet) ||
-                    l_method->getPrivate()->projMethodOverride_ == "etmerc";
-        if (isUTM(zone, north) && !(etMercSettingSet && !useETMerc)) {
+        useApprox =
+            formatter->getUseApproxTMerc() ||
+            l_method->getPrivate()->projMethodOverride_ == "tmerc approx" ||
+            l_method->getPrivate()->projMethodOverride_ == "utm approx";
+        if (isUTM(zone, north)) {
             bConversionDone = true;
             formatter->addStep("utm");
+            if( useApprox ) {
+                formatter->addParam("approx");
+            }
             formatter->addParam("zone", zone);
             if (!north) {
                 formatter->addParam("south");
@@ -5662,7 +5664,10 @@ void Conversion::_exportToPROJString(
     if (!bConversionDone) {
         const MethodMapping *mapping = getMapping(l_method.get());
         if (mapping && mapping->proj_name_main) {
-            formatter->addStep(useETMerc ? "etmerc" : mapping->proj_name_main);
+            formatter->addStep(mapping->proj_name_main);
+            if (useApprox) {
+                formatter->addParam("approx");
+            }
             if (mapping->proj_name_aux) {
                 if (internal::starts_with(mapping->proj_name_aux, "axis=")) {
                     bAxisSpecFound = true;

src/iso19111/io.cpp

@@ -4746,8 +4746,7 @@ struct PROJStringFormatter::Private {
     bool omitProjLongLatIfPossible_ = false;
     bool omitZUnitConversion_ = false;
     DatabaseContextPtr dbContext_{};
-    bool useETMercForTMerc_ = false;
-    bool useETMercForTMercSet_ = false;
+    bool useApproxTMerc_ = false;
     bool addNoDefs_ = true;
     bool coordOperationOptimizations_ = false;
     bool crsExport_ = false;
@@ -4803,11 +4802,9 @@ PROJStringFormatter::create(Convention conventionIn,
 
 // ---------------------------------------------------------------------------
 
-/** \brief Set whether Extended Transverse Mercator (etmerc) should be used
- * instead of tmerc */
-void PROJStringFormatter::setUseETMercForTMerc(bool flag) {
-    d->useETMercForTMerc_ = flag;
-    d->useETMercForTMercSet_ = true;
+/** \brief Set whether approximate Transverse Mercator or UTM should be used */
+void PROJStringFormatter::setUseApproxTMerc(bool flag) {
+    d->useApproxTMerc_ = flag;
 }
 
 // ---------------------------------------------------------------------------
@@ -5256,9 +5253,8 @@ PROJStringFormatter::Convention PROJStringFormatter::convention() const {
 
 // ---------------------------------------------------------------------------
 
-bool PROJStringFormatter::getUseETMercForTMerc(bool &settingSetOut) const {
-    settingSetOut = d->useETMercForTMercSet_;
-    return d->useETMercForTMerc_;
+bool PROJStringFormatter::getUseApproxTMerc() const {
+    return d->useApproxTMerc_;
 }
 
 // ---------------------------------------------------------------------------
@@ -7081,8 +7077,10 @@ CRSNNPtr PROJStringParser::Private::buildProjectedCRS(
                                 : UnitOfMeasure::NONE)));
         }
 
-        if (step.name == "etmerc") {
-            methodMap.set("proj_method", "etmerc");
+        if (step.name == "tmerc" && hasParamValue(step, "approx")) {
+            methodMap.set("proj_method", "tmerc approx");
+        } else if (step.name == "utm" && hasParamValue(step, "approx")) {
+            methodMap.set("proj_method", "utm approx");
         }
 
         conv = Conversion::create(mapWithUnknownName, methodMap, parameters,

src/lib_proj.cmake

@@ -117,7 +117,6 @@ SET(SRC_LIBPROJ_PROJECTIONS
         projections/wag7.cpp
         projections/lcca.cpp
         projections/geos.cpp
-        projections/etmerc.cpp
         projections/boggs.cpp
         projections/collg.cpp
         projections/comill.cpp