GPA

backend/src/utils/applicationCalculations.js

@@ -27,53 +27,52 @@ function calculateLiquidApplication(areaSquareFeet, rateAmount, rateUnit, equipm
     Equipment: ${equipment?.categoryName} (width: ${equipment?.sprayWidthFeet || 'N/A'} ft)
     Nozzle GPM: ${nozzle?.flowRateGpm || 'N/A'}`);
 
-  // Calculate application speed first based on equipment and nozzle
-  if (equipment && nozzle && nozzle.flowRateGpm && equipment.sprayWidthFeet) {
-    const sprayWidthFeet = equipment.sprayWidthFeet;
-    const nozzleGpm = nozzle.flowRateGpm;
-    
-    // For liquid applications, we need to determine optimal speed based on target carrier rate
-    // Let's use a reasonable default carrier rate of 20 GPA (gallons per acre)
-    const targetGallonsPerAcre = 20;
-    const targetGallonsPerSqft = targetGallonsPerAcre / 43560;
-    
-    // Formula: Speed (MPH) = GPM / (width_ft × target_rate_gal_per_sqft × 88)
-    // Where 88 converts MPH to ft/min
-    applicationSpeedMph = nozzleGpm / (sprayWidthFeet * targetGallonsPerSqft * 88);
-    
-    // Limit speed to reasonable range (1-8 MPH for lawn applications)
-    applicationSpeedMph = Math.max(1, Math.min(8, applicationSpeedMph));
-  } else {
-    applicationSpeedMph = 3; // Default speed
-  }
+  // Use a practical application speed for lawn treatments
+  applicationSpeedMph = 3; // Standard walking speed for most lawn applications
 
-  // Now calculate actual carrier (water) rate using the calculated speed
+  // Calculate actual carrier (water) rate based on equipment specs and application speed
   // Formula: Rate (gal/sqft) = flow (GPM) / (width (ft) × speed (ft/min))
   // Where speed (ft/min) = speed (MPH) × 88
   let carrierRateGalPerSqft = 0;
+  let actualGallonsPerAcre = 0;
   
   if (equipment && nozzle && nozzle.flowRateGpm && equipment.sprayWidthFeet) {
     const flowGpm = nozzle.flowRateGpm;
     const widthFt = equipment.sprayWidthFeet;
     const speedFtPerMin = applicationSpeedMph * 88; // Convert MPH to ft/min
     
+    // Calculate carrier rate based on actual equipment parameters
     carrierRateGalPerSqft = flowGpm / (widthFt * speedFtPerMin);
     waterGallons = carrierRateGalPerSqft * areaSquareFeet;
     
-    console.log('Carrier rate calculation:', {
+    // Calculate the resulting GPA for reference
+    actualGallonsPerAcre = carrierRateGalPerSqft * 43560;
+    
+    console.log('Equipment-based carrier rate calculation:', {
       flowGpm,
       widthFt,
       speedMph: applicationSpeedMph,
       speedFtPerMin,
-      carrierRateGalPerSqft,
+      carrierRateGalPerSqft: carrierRateGalPerSqft.toFixed(6),
       areaSquareFeet,
-      totalWaterGallons: waterGallons,
-      carrierRateGalPer1000Sqft: carrierRateGalPerSqft * 1000
+      totalWaterGallons: waterGallons.toFixed(2),
+      resultingGPA: actualGallonsPerAcre.toFixed(1),
+      carrierRateGalPer1000Sqft: (carrierRateGalPerSqft * 1000).toFixed(3)
     });
   } else {
-    // Fallback to area-based calculation if equipment data is missing
+    // Fallback when equipment/nozzle data is missing
     console.log('Using fallback water calculation - missing equipment/nozzle data');
-    waterGallons = area1000sqft * 0.164; // Use your example: 0.164 gal/1000sqft
+    // Use a reasonable default rate for lawn applications (25 GPA)
+    const fallbackGPA = 25;
+    const fallbackRatePerSqft = fallbackGPA / 43560;
+    waterGallons = fallbackRatePerSqft * areaSquareFeet;
+    actualGallonsPerAcre = fallbackGPA;
+    
+    console.log('Fallback calculation:', {
+      fallbackGPA,
+      areaSquareFeet,
+      totalWaterGallons: waterGallons.toFixed(2)
+    });
   }
 
   // Calculate product amount based on rate unit