AsciiRasterInterface.cpp

Go to the documentation of this file.

 
#include "AsciiRasterInterface.h"
 
#include <tuple>
 
#include "BaseLib/FileTools.h"
#include "BaseLib/Logging.h"
#include "BaseLib/StringTools.h"
 
namespace FileIO
{
GeoLib::Raster* AsciiRasterInterface::readRaster(std::string const& fname)
{
    std::string ext(BaseLib::getFileExtension(fname));
    std::transform(ext.begin(), ext.end(), ext.begin(), tolower);
    if (ext == ".asc")
    {
        return getRasterFromASCFile(fname);
    }
    if (ext == ".grd")
    {
        return getRasterFromSurferFile(fname);
    }
    return nullptr;
}
 
static double readDoubleFromStream(std::istream& in)
{
    std::string value;
    in >> value;
    return std::strtod(BaseLib::replaceString(",", ".", value).c_str(),
                       nullptr);
}
 
static std::optional<GeoLib::RasterHeader> readASCHeader(std::ifstream& in)
{
    GeoLib::RasterHeader header;
 
    std::string tag;
    std::string value;
 
    in >> tag;
    if (tag == "ncols")
    {
        in >> value;
        header.n_cols = atoi(value.c_str());
    }
    else
    {
        return {};
    }
 
    in >> tag;
    if (tag == "nrows")
    {
        in >> value;
        header.n_rows = atoi(value.c_str());
    }
    else
    {
        return {};
    }
 
    header.n_depth = 1;
 
    in >> tag;
    if (tag == "xllcorner" || tag == "xllcenter")
    {
        header.origin[0] = readDoubleFromStream(in);
    }
    else
    {
        return {};
    }
 
    in >> tag;
    if (tag == "yllcorner" || tag == "yllcenter")
    {
        header.origin[1] = readDoubleFromStream(in);
    }
    else
    {
        return {};
    }
    header.origin[2] = 0;
 
    in >> tag;
    if (tag == "cellsize")
    {
        header.cell_size = readDoubleFromStream(in);
    }
    else
    {
        return {};
    }
 
    in >> tag;
    if (tag == "NODATA_value" || tag == "nodata_value")
    {
        header.no_data = readDoubleFromStream(in);
    }
    else
    {
        return {};
    }
 
    return header;
}
 
GeoLib::Raster* AsciiRasterInterface::getRasterFromASCFile(
    std::string const& fname)
{
    std::ifstream in(fname.c_str());
 
    if (!in.is_open())
    {
        WARN("Raster::getRasterFromASCFile(): Could not open file {:s}.",
             fname);
        return nullptr;
    }
 
    auto const header = readASCHeader(in);
    if (!header)
    {
        WARN(
            "Raster::getRasterFromASCFile(): Could not read header of file "
            "{:s}",
            fname);
        return nullptr;
    }
 
    std::vector<double> values(header->n_cols * header->n_rows);
    // read the data into the double-array
    for (std::size_t j(0); j < header->n_rows; ++j)
    {
        const std::size_t idx((header->n_rows - j - 1) * header->n_cols);
        for (std::size_t i(0); i < header->n_cols; ++i)
        {
            values[idx + i] = readDoubleFromStream(in);
        }
    }
 
    return new GeoLib::Raster(*header, values.begin(), values.end());
}
 
static std::optional<std::tuple<GeoLib::RasterHeader, double, double>>
readSurferHeader(std::ifstream& in)
{
    std::string tag;
 
    in >> tag;
 
    if (tag != "DSAA")
    {
        ERR("Error in readSurferHeader() - No Surfer file.");
        return {};
    }
 
    GeoLib::RasterHeader header;
    in >> header.n_cols >> header.n_rows;
    double min, max;
    in >> min >> max;
    header.origin[0] = min;
    header.cell_size = (max - min) / static_cast<double>(header.n_cols);
 
    in >> min >> max;
    header.origin[1] = min;
    header.origin[2] = 0;
 
    if (ceil((max - min) / static_cast<double>(header.n_rows)) ==
        ceil(header.cell_size))
    {
        header.cell_size = ceil(header.cell_size);
    }
    else
    {
        ERR("Error in readSurferHeader() - Anisotropic cellsize detected.");
        return {};
    }
    header.n_depth = 1;
    header.no_data = min - 1;
    in >> min >> max;
 
    return {{header, min, max}};
}
 
GeoLib::Raster* AsciiRasterInterface::getRasterFromSurferFile(
    std::string const& fname)
{
    std::ifstream in(fname.c_str());
 
    if (!in.is_open())
    {
        ERR("Raster::getRasterFromSurferFile() - Could not open file {:s}",
            fname);
        return nullptr;
    }
 
    auto const optional_header = readSurferHeader(in);
    if (!optional_header)
    {
        ERR("Raster::getRasterFromASCFile() - could not read header of file "
            "{:s}",
            fname);
        return nullptr;
    }
 
    auto const [header, min, max] = *optional_header;
    const double no_data_val(min - 1);
    std::vector<double> values(header.n_cols * header.n_rows);
    // read the data into the double-array
    for (std::size_t j(0); j < header.n_rows; ++j)
    {
        const std::size_t idx(j * header.n_cols);
        for (std::size_t i(0); i < header.n_cols; ++i)
        {
            const double val = readDoubleFromStream(in);
            values[idx + i] = (val > max || val < min) ? no_data_val : val;
        }
    }
 
    return new GeoLib::Raster(header, values.begin(), values.end());
}
 
void AsciiRasterInterface::writeRasterAsASC(GeoLib::Raster const& raster,
                                            std::string const& file_name)
{
    GeoLib::RasterHeader header(raster.getHeader());
    MathLib::Point3d const& origin(header.origin);
    unsigned const nCols(header.n_cols);
    unsigned const nRows(header.n_rows);
 
    // write header
    std::ofstream out(file_name);
    out << "ncols " << nCols << "\n";
    out << "nrows " << nRows << "\n";
    auto const default_precision = out.precision();
    out.precision(std::numeric_limits<double>::digits10);
    out << "xllcorner " << origin[0] << "\n";
    out << "yllcorner " << origin[1] << "\n";
    out << "cellsize " << header.cell_size << "\n";
    out.precision(default_precision);
    out << "NODATA_value " << header.no_data << "\n";
 
    // write data
    double const* const elevation(raster.begin());
    for (unsigned row(0); row < nRows; ++row)
    {
        for (unsigned col(0); col < nCols - 1; ++col)
        {
            out << elevation[(nRows - row - 1) * nCols + col] << " ";
        }
        out << elevation[(nRows - row) * nCols - 1] << "\n";
    }
    out.close();
}
 
static bool allRastersExist(std::vector<std::string> const& raster_paths)
{
    for (const auto& raster_path : raster_paths)
    {
        std::ifstream file_stream(raster_path, std::ifstream::in);
        if (!file_stream.good())
        {
            return false;
        }
        file_stream.close();
    }
    return true;
}
 
std::optional<std::vector<GeoLib::Raster const*>> readRasters(
    std::vector<std::string> const& raster_paths)
{
    if (!allRastersExist(raster_paths))
    {
        return std::nullopt;
    }
 
    std::vector<GeoLib::Raster const*> rasters;
    rasters.reserve(raster_paths.size());
    std::transform(raster_paths.begin(), raster_paths.end(),
                   std::back_inserter(rasters),
                   [](auto const& path)
                   { return FileIO::AsciiRasterInterface::readRaster(path); });
    return std::make_optional(rasters);
}
}  // end namespace FileIO