OpenTopography_DEMDownloader_algorithm.py

# -*- coding: utf-8 -*-

"""
/***************************************************************************
 OpenTopographyDEMDownloader
                                 A QGIS plugin
 This plugin downloads DEM from OpenTopography.org
 Generated by Plugin Builder: http://g-sherman.github.io/Qgis-Plugin-Builder/
                              -------------------
        begin                : 2022-01-27
        copyright            : (C) 2022 by Kyaw Naing Win
        email                : kyawnaingwinknw@gmail.com
 ***************************************************************************/

/***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/
"""

__author__ = 'Kyaw Naing Win'
__date__ = '2022-01-27'
__copyright__ = '(C) 2022 by Kyaw Naing Win'

# This will get replaced with a git SHA1 when you do a git archive
__revision__ = '$Format:%H$'

import os
import requests

from qgis.PyQt.QtCore import QCoreApplication
from qgis.PyQt.QtGui import QIcon
from qgis.core import (QgsProcessingAlgorithm,
                       QgsProcessingParameterString,
                       QgsProcessingParameterExtent,
                       QgsProcessingParameterEnum,
                       QgsProcessingException,
                       QgsProcessingParameterRasterDestination,
                       QgsCoordinateTransform,
                       QgsCoordinateReferenceSystem,
                       QgsProject,
                       QgsSettings)
import processing


class OpenTopographyDEMDownloaderAlgorithm(QgsProcessingAlgorithm):

    OUTPUT = 'OUTPUT'
    INPUT = 'INPUT'

    def initAlgorithm(self, config):
        settings = QgsSettings()
        ot_auth_token = settings.value("OpenTopographyDEMDownloader/ot_api_key", "")
        if not ot_auth_token:
            auth_prompt = self.tr('Enter OpenTopography access key')
        else:
            auth_prompt = self.tr('Enter OpenTopography access key (or use existing one below)')

        self.addParameter(
            QgsProcessingParameterEnum(
                'DEMs',
                'Select DEM to download',
                options=[
                         'Agência Nacional de Águas DEM (ANADEM) 30m',
                         'ALOS World 3D 30m',
                         'ALOS World 3D Ellipsoidal 30m',
                         'Copernicus Global DSM 30m',
                         'Copernicus Global DSM 90m',
                         'EU DTM 30m',
                         'GEBCOIceTopo Bathymetry 500m',
                         'GEBCOSubIceTopo Bathymetry 500m',
                         'GEDI L3 1km',
                         'Global Bathymetry SRTM15+ V2.55 500m',
                         'Global Ensemble Digital Terrain Model 30m',
                         'NASADEM Global DEM 30m',
                         'SRTM 30m',
                         'SRTM 90m',
                         'SRTM GL1 Ellipsoidal 30m'
                ],
                allowMultiple=False,
                defaultValue=[13]
            )
        )
        self.addParameter(QgsProcessingParameterExtent('Extent', 'Define extent to download', defaultValue=None))
        self.addParameter(QgsProcessingParameterString('OT_AUTH_TOKEN', auth_prompt, multiLine=False, defaultValue=ot_auth_token))
        self.addParameter(QgsProcessingParameterRasterDestination(self.OUTPUT, self.tr('Output Raster')))

    def processAlgorithm(self, parameters, context, feedback):
        settings = QgsSettings()
        outputs = {}

        # process extent bbox information
        crs = self.parameterAsExtentCrs(parameters, "Extent", context)
        extent = self.parameterAsExtentGeometry(
            parameters, "Extent", context
        ).boundingBox()

        if crs.authid() != "EPSG:4326":
            extent = QgsCoordinateTransform(
                crs,
                QgsCoordinateReferenceSystem("EPSG:4326"),
                QgsProject.instance(),
            ).transformBoundingBox(extent)

        dem_codes = [
                     'ANADEM',
                     'AW3D30',
                     'AW3D30_E',
                     'COP30',
                     'COP90',
                     'EU_DTM',
                     'GEBCOIceTopo',
                     'GEBCOSubIceTopo',
                     'GEDI_L3',
                     'SRTM15Plus',
                     'GEDTM30',
                     'NASADEM',
                     'SRTMGL1',
                     'SRTMGL3',
                     'SRTMGL1_E'

        ]

        dem_code = dem_codes[parameters['DEMs']]

        south = extent.yMinimum()
        north = extent.yMaximum()
        west = extent.xMinimum()
        east = extent.xMaximum()
        
        # check bounding box if ANADEM is selected
        anadem_north = 14.07948
        anadem_south = -56.51552
        anadem_east= -34.72655
        anadem_west= -82.51655
        
        if dem_code == 'ANADEM':
            
            # 1. Check if the extent INTERSECTS with ANADEM extent
            intersects = (
                west <= anadem_east and
                east >= anadem_west and
                south <= anadem_north and
                north >= anadem_south
            )

            # 2. Check if the extent is COMPLETELY WITHIN ANADEM extent
            is_within = (
                west >= anadem_west and
                east <= anadem_east and
                south >= anadem_south and
                north <= anadem_north
            )
            if not intersects:
                feedback.reportError(
                "Selected extent is completely outside the ANADEM coverage area_South Amearica. Process cancelled.",
                fatalError=False
                )
                return {} #just waiting to correct the error
            
            elif not is_within:
                feedback.pushWarning("Selected extent extends beyond the ANADEM coverage area. But only avaiable data will be downloaded")
        
        dem_url = (
            f"https://portal.opentopography.org/API/globaldem?demtype={dem_code}"
            f"&south={south}&north={north}&west={west}&east={east}&outputFormat=GTiff"
        )
        dem_url = dem_url + "&API_Key=" + parameters['OT_AUTH_TOKEN']

        dem_file = self.parameterAsFileOutput(parameters, self.OUTPUT, context)
        try:
            # Download file
            alg_params = {
                'URL': dem_url,
                'OUTPUT': dem_file
            }
            outputs['DownloadFile'] = processing.run(
                'native:filedownloader',
                alg_params,
                context=context,
                feedback=feedback,
                is_child_algorithm=True
            )
            settings.setValue("OpenTopographyDEMDownloader/ot_api_key", parameters['OT_AUTH_TOKEN'])
        except Exception:
            response = requests.request("GET", dem_url, headers={}, data={})
            raise QgsProcessingException(response.text.split('<error>')[1][:-8])

        # Load layer into project
        dem_file_name = os.path.basename(dem_file)
        if dem_file_name == 'OUTPUT.tif':
            alg_params = {
                'INPUT': outputs['DownloadFile']['OUTPUT'],
                'NAME': dem_code + "[Memory]"
            }
        else:
            alg_params = {
                'INPUT': dem_file,
                'NAME': dem_file_name
            }
        outputs['LoadLayerIntoProject'] = processing.run(
            'native:loadlayer',
            alg_params,
            context=context,
            feedback=feedback,
            is_child_algorithm=True
        )

        return {self.OUTPUT: outputs['DownloadFile']['OUTPUT']}

    def name(self):
        """
        Returns the algorithm name, used for identifying the algorithm. This
        string should be fixed for the algorithm, and must not be localised.
        The name should be unique within each provider. Names should contain
        lowercase alphanumeric characters only and no spaces or other
        formatting characters.
        """
        return 'OpenTopography DEM Downloader'

    def displayName(self):
        """
        Returns the translated algorithm name, which should be used for any
        user-visible display of the algorithm name.
        """
        return self.tr(self.name())

    def group(self):
        """
        Returns the name of the group this algorithm belongs to. This string
        should be localised.
        """
        return self.tr(self.groupId())

    def groupId(self):
        """
        Returns the unique ID of the group this algorithm belongs to. This
        string should be fixed for the algorithm, and must not be localised.
        The group id should be unique within each provider. Group id should
        contain lowercase alphanumeric characters only and no spaces or other
        formatting characters.
        """
        return 'DEM Downloader'

    def tr(self, string):
        return QCoreApplication.translate('Processing', string)

    def icon(self):
        cmd_folder = os.path.dirname(__file__)
        icon_path = os.path.join(cmd_folder, 'icon.png')
        return QIcon(icon_path)

    def shortHelpString(self):
        help_text = """               
        This tool will download DEM for the extent defined by user, from OpenTopography (https://opentopography.org/)
        
        As of Jan 2022, an access key is required for all DEMs. 
        Read https://opentopography.org/blog/introducing-api-keys-access-opentopography-global-datasets how to get an access key.
        
        Developed by: Kyaw Naing Win
        
        Version: 4.2
        Date: 2026-07-16
        
        change log ver4.2:
        - Agência Nacional de Águas DEM (ANADEM, 30m) for South America and Global Ensemble Digital Terrain Model (30m) are added into the DEM list
        
        change log ver4.1:
         - Fixed security warnings regarding API key keywords
        
        change log ver4: 
         - Compatible with both QGIS 3.x and GIS 4.x versions
        
        change log ver3: 
         - GEBCOIceTopo Bathymetry 500m and GEBCOSubIceTopo Bathymetry 500m datasets are added into the DEM list
        
        change log ver2:
         - EU DTM and GEDI L3 Grid are added into the DEM list
         - Errors returned from the OpenTopography site are displayed
         - Accept layer model input as extent input in Graphical Modeler (credit: Suricactus https://github.com/suricactus) 
         
        email: kyawnaingwinknw@gmail.com 
        
        read more: https://github.com/knwin/OpenTopography-DEM-Downloader-qgis-plugin

        """
        return self.tr(help_text)

    def createInstance(self):
        return OpenTopographyDEMDownloaderAlgorithm()