The following C++ class serves as an example of how to generate the traditional VPD charts using the classes provided in this thread. Here is an example of the generated VPD charts for the difference stages in a plants life where there is no temperature difference between the leaf and the surrounding atmosphere.
The values will vary depending on the leaf temperatures which hints towards more complexity ahead, transpiration.
Edit: Changed units to celcius
Edit: 9-2 made the text COLOR namespace anonymous to avoid namespace conflicts.
Example generated VPD for propagation and early vegetation with leaf temperature same as environment
Example generated VPD during late vegetation and early flowering with leaf temperature same as environment
Example generated VPD during mid to late flowering with leaf temperature same as environment
//
// vpd_text_table.h
//
// Copyright (c) 2018 Northern_Loki (sha256::6F290BF833967127BE26C92C8F6B1C1A3949C55A7EABCEF3ECC785CD2D38D30D)
// License granted under the Creative Commons Attribution-ShareAlike 4.0 International. https://creativecommons.org/licenses/by-sa/4.0/
//
# pragma once
# include <ostream>
# include <boost/format.hpp>
# include "vpd.h"
class vpd_text_table : public vpd, farenheit
{
public:
vpd_text_table();
vpd_text_table(float leaf_temperature_differential);
~vpd_text_table();
void print_table(float temperature_difference, float min, float max);
};//
// vpd_text_table.cpp
//
// Copyright (c) 2018 Northern_Loki (sha256::6F290BF833967127BE26C92C8F6B1C1A3949C55A7EABCEF3ECC785CD2D38D30D)
// License granted under the Creative Commons Attribution-ShareAlike 4.0 International. https://creativecommons.org/licenses/by-sa/4.0/
//
// This source serves as an example of utilizing the vpd class to generate vpd charts.
//
// Usage example:
//
// // Generate charts for the case where leaf temperature difference is known to be 1 degree greater than the environment.
// vpd_text_table(1);
//
// // Generate charts for the case where leaf temperature difference is unknown or the leaf temperature equals the environment.
// vpd_text_table();
# include "vpd_text_table.h"
namespace
{
enum Code
{
FG_RED = 31,
FG_GREEN = 32,
FG_YELLOW = 33,
FG_BLUE = 34,
FG_MAGENTA = 35,
FG_DEFAULT = 39,
BG_RED = 41,
BG_GREEN = 42,
BG_BLUE = 44,
BG_DEFAULT = 49
};
std::ostream& operator<<(std::ostream& os, Code code)
{
return os << "\033[" << static_cast<int>(code) << "m";
}
}
/* Calculate and print VPD tables for the case where the leaf temperatures are the same as the atmosphere. */
vpd_text_table::vpd_text_table()
{
/* The following are examples VPD values for different stages of plant growth */
/* VPD is actually quite a bit more complicated than simply looking at temperature and humidity */
/* but, this will provide a general goal until you are looking at actual transpiration estimations. Set these to your expectations. */
float early_veg_min = 0.4;
float early_veg_max = 0.8;
float late_veg_min = 0.8;
float late_veg_max = 1.2;
float late_flower_min = 1.2;
float late_flower_max = 1.6;
float leaf_diff = 0;
std::cout << boost::format("%=8i") % " " << "Suggested VPD during propagation and early vegetation:" << std::endl;
print_table(leaf_diff, early_veg_min, early_veg_max);
std::cout << boost::format("%=8i") % " " << "Suggested VPD during late vegetation and early flowering:" << std::endl;
print_table(leaf_diff, late_veg_min, late_veg_max);
std::cout << boost::format("%=8i") % " " << "Suggested VPD during mid to late flowering:" << std::endl;
print_table(leaf_diff, late_flower_min, late_flower_max);
}
/* Calculate and print VPD tables for the case where the leaf temperatures are different than the surrounding atmosphere. */
/* leaf_temperature_differential is the difference between the leaf and the atmosphere in degrees celcius */
vpd_text_table::vpd_text_table(float leaf_temperature_differential)
{
/* The following are examples VPD values for different stages of plant growth */
/* VPD is actually quite a bit more complicated than simply looking at temperature and humidity */
/* but, this will provide a general goal until you are looking at actual transpiration estimations. Set these to your expectations. */
float early_veg_min = 0.4;
float early_veg_max = 0.8;
float late_veg_min = 0.8;
float late_veg_max = 1.2;
float late_flower_min = 1.2;
float late_flower_max = 1.6;
float leaf_diff = leaf_temperature_differential;
std::cout << boost::format("%=8i") % " " << "Suggested VPD during" << FG_YELLOW << " propagation and early vegetation" << FG_DEFAULT << " with leaf temperature difference of " << leaf_temperature_differential << " degree :" << std::endl;
print_table(leaf_diff, early_veg_min, early_veg_max);
std::cout << boost::format("%=8i") % " " << "Suggested VPD during" << FG_YELLOW << " late vegetation and early flowering" << FG_DEFAULT << " with leaf temperature difference of " << leaf_temperature_differential << " degree :" << std::endl;
print_table(leaf_diff, late_veg_min, late_veg_max);
std::cout << boost::format("%=8i") % " " << "Suggested VPD during" << FG_YELLOW << " mid to late flowering" << FG_DEFAULT << " with leaf temperature difference of " << leaf_temperature_differential << " degree :" << std::endl;
print_table(leaf_diff, late_flower_min, late_flower_max);
}
vpd_text_table::~vpd_text_table()
{
}
void vpd_text_table::print_table(float temperature_difference, float min, float max)
{
float humidity = 0;
float humidity_step = 5;
celcius temperature = 0;
std::cout << boost::format("%=8i") % " " << FG_BLUE << "Relative Humidity (\%) ----->" << FG_DEFAULT << std::endl;
std::cout << boost::format("%=8i|") % " ";
for (humidity = 0; humidity <= 100; humidity += humidity_step)
{
std::cout << boost::format("%=8s|") % "--------";
}
std::cout << std::endl;
std::cout << boost::format("%=8i|") % " ";
for (humidity = 0; humidity <= 100; humidity += humidity_step)
{
std::cout << boost::format("%=8i|") % humidity;
}
std::cout << std::endl;
int temp_string_cnt = 0;
const char temp_string[255] = " Temperature degrees celcius ";
for (temperature = 5; temperature <= 40; temperature += 1)
{
std::cout << FG_BLUE << boost::format("%=1c") % temp_string[temp_string_cnt++] << FG_DEFAULT;
std::cout << boost::format("%=7i|") % " ";
for (humidity = 0; humidity <= 100; humidity += humidity_step)
{
std::cout << boost::format("%=8s|") % "--------";
}
std::cout << std::endl;
std::cout << FG_BLUE << boost::format("%=1c") % temp_string[temp_string_cnt++] << FG_DEFAULT;
std::cout << boost::format("%=7i|") % temperature;
for (humidity = 0; humidity <= 100; humidity += humidity_step)
{
vpd pressure_deficit = vpd(temperature, temperature + temperature_difference, (float)humidity / 100.0);
if ((pressure_deficit() < min) || (pressure_deficit() > max))
{
std::cout << FG_RED << boost::format("%=8.3f") % pressure_deficit << FG_DEFAULT << "|";
}
else
{
std::cout << FG_GREEN << boost::format("%=8.3f") % pressure_deficit << FG_DEFAULT << "|";
}
}
std::cout << std::endl;
}
std::cout << boost::format("%=8i|") % " ";
for (humidity = 0; humidity <= 100; humidity += humidity_step)
{
std::cout << boost::format("%=8s|") % "--------";
}
std::cout << std::endl << std::endl;
}