Coded location

wxdata/source/scwx/awips/coded_location.cpp

@@ -0,0 +1,155 @@
+#include <scwx/awips/coded_location.hpp>
+
+#include <sstream>
+
+#include <boost/log/trivial.hpp>
+
+namespace scwx
+{
+namespace awips
+{
+
+static const std::string logPrefix_ = "[scwx::awips::coded_location] ";
+
+class CodedLocationImpl
+{
+public:
+   explicit CodedLocationImpl() : coordinates_ {} {}
+
+   ~CodedLocationImpl() {}
+
+   std::vector<common::Coordinate> coordinates_;
+};
+
+CodedLocation::CodedLocation() : p(std::make_unique<CodedLocationImpl>()) {}
+CodedLocation::~CodedLocation() = default;
+
+CodedLocation::CodedLocation(CodedLocation&&) noexcept = default;
+CodedLocation& CodedLocation::operator=(CodedLocation&&) noexcept = default;
+
+std::vector<common::Coordinate> CodedLocation::coordinates() const
+{
+   return p->coordinates_;
+}
+
+bool CodedLocation::Parse(const StringRange& lines, const std::string& wfo)
+{
+   enum class LocationFormat
+   {
+      WFO,
+      NationalCenter
+   };
+
+   bool           dataValid = true;
+   LocationFormat format;
+
+   std::vector<std::string> tokenList;
+
+   for (std::string line : lines)
+   {
+      std::string        token;
+      std::istringstream tokenStream {line};
+
+      while (tokenStream >> token)
+      {
+         tokenList.push_back(token);
+      }
+   }
+
+   // First token is "LAT...LON"
+   // At a minimum, three points (latitude/longitude pairs) will be included
+   dataValid = (tokenList.size() >= 4 && tokenList.at(0) == "LAT...LON");
+
+   if (dataValid)
+   {
+      format = (tokenList.at(1).size() == 8) ? LocationFormat::NationalCenter :
+                                               LocationFormat::WFO;
+
+      if (format == LocationFormat::WFO)
+      {
+         dataValid = (tokenList.size() >= 7 && tokenList.size() % 2 == 1);
+      }
+   }
+
+   if (dataValid)
+   {
+      if (format == LocationFormat::WFO)
+      {
+         const bool wfoIsWest         = (wfo != "PGUM");
+         double     westLongitude     = (wfoIsWest) ? -1.0 : 1.0;
+         bool       straddlesDateLine = false;
+
+         for (auto token = tokenList.cbegin() + 1; token != tokenList.cend();
+              ++token)
+         {
+            double latitude = std::stod(*token) * 0.01;
+            ++token;
+            double longitude = std::stod(*token) * 0.01;
+
+            // If a given product straddles 180 degrees longitude, those points
+            // west of 180 degrees will be given as if they were west longitude
+            if (longitude > 180.0)
+            {
+               longitude -= 360.0;
+               straddlesDateLine = true;
+            }
+
+            longitude *= westLongitude;
+
+            p->coordinates_.push_back({latitude, longitude});
+         }
+
+         if (!wfoIsWest && straddlesDateLine)
+         {
+            for (auto& coordinate : p->coordinates_)
+            {
+               coordinate.longitude_ *= -1.0;
+            }
+         }
+      }
+      else
+      {
+         for (auto token = tokenList.cbegin() + 1; token != tokenList.cend();
+              ++token)
+         {
+            if (token->size() != 8)
+            {
+               dataValid = false;
+               break;
+            }
+
+            double latitude  = std::stod(token->substr(0, 4)) * 0.01;
+            double longitude = std::stod(token->substr(4, 4)) * -0.01;
+
+            // Longitudes of greater than 100 degrees will drop the leading 1;
+            // i.e., 105.22 W would be coded as 0522.  This is ambiguous
+            // with 5.22 W, so we assume everything east of 65 W (east of Maine,
+            // easternmost point of CONUS) should have 100 degrees added to it.
+            // Points in the Atlantic or western Alaska will not be correct, but
+            // it is assumed that products will not contain those points coded
+            // using this methodology.
+            if (longitude > -65.0)
+            {
+               longitude -= 100.0;
+            }
+
+            p->coordinates_.push_back({latitude, longitude});
+         }
+      }
+   }
+
+   if (dataValid)
+   {
+      // If the last point is a repeat of the first point, remove it as
+      // redundant
+      if (p->coordinates_.front() == p->coordinates_.back())
+      {
+         p->coordinates_.pop_back();
+      }
+   }
+
+   return dataValid;
+}
+
+} // namespace awips
+} // namespace scwx