ImageLoader

ImageLoader is a QGIS plugin that allows users to click on polygons (e.g., grid tiles) to automatically load and display associated raster images from a local folder. The plugin supports customizable filename patterns using prefixes and suffixes, and provides an interactive interface for selecting the input layer, field, and image directory.

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Features

• Click a polygon on the QGIS map canvas to load corresponding raster images based on a specified field value.
• Support for customizable filename patterns with optional prefix and suffix inputs.
• Interactive dialog to select a polygon layer, field containing the raster name/code, and image folder.
• Visual feedback with a temporary red rubber band highlighting the clicked polygon.
• Custom cursor (32x32 pixel cursor.png) for precise clicking, with fallback to a cross cursor.
• Supports common raster formats (.tif, .tiff, .jp2, .jpeg, .jpg, .png).
• Error handling for invalid layers, fields, or folders with user-friendly messages.

Example Use Case

If your raster folder contains files like:

• ortho_999999.jp2
• ortho_999998.tiff
• ortho_999997.tif

And your polygon layer has a field tile_code with values 999999, 999998, 999997, you can set:

• Prefix: ortho_
• Suffix: leave it blank

Then, clicking on a tile will load the matching raster (e.g., ortho_999999.jp2) directly into QGIS.

You can set Prefix or Suffix or both Prefix and Suffix or leave it blank (e.g., ortho_999999_georef.jp2, or 999998_ortho.tiff, or 999997.png).

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How It Works

1. Activate the plugin via the toolbar icon or the "Image Loader" menu to open the settings dialog.
2. Select a polygon layer containing the grid cells.
3. Choose the field that contains the raster name or code.
4. Specify the folder containing the raster images and optional filename prefix/suffix.
5. Click "Activate" to enable the map tool.
6. Click a polygon on the map canvas to load associated raster images, with a temporary red highlight on the selected polygon.
7. Press Esc to deactivate the tool.

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Installation

1. Clone or download this repository:

   git clone https://github.com/Consortis-Geospatial/ImageLoader.git

2. Copy the folder to your QGIS plugin directory:
   • Linux: ~/.local/share/QGIS/QGIS3/profiles/default/python/plugins/
   • Windows: %APPDATA%\QGIS\QGIS3\profiles\default\python\plugins\
   • macOS: ~/Library/Application Support/QGIS/QGIS3/profiles/default/python/plugins/
3. Ensure the cursor.png (32x32 pixel image) is included in the plugin folder for the custom cursor.
4. Open QGIS and enable the plugin via Plugins > Manage and Install Plugins.

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Screenshot

Coming Soon...

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Developer Notes

• Developed in Python using PyQt and PyQGIS APIs.
• Uses a custom QDialog for configuring layer, field, folder, and filename patterns.
• Employs a custom QgsMapTool based on QgsMapToolIdentifyFeature to handle polygon clicks and load rasters.
• Temporary red QgsRubberBand visualization for 100ms to highlight selected polygons.
• Supports raster loading with QgsRasterLayer and filename pattern matching via glob.
• Includes robust error handling for invalid inputs, missing files, or layer issues.
• Compatible with QGIS 3.0 and later.

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Dependencies

• QGIS 3.x: Compatible with QGIS version 3.0 and later (tested with 3.38.3), providing the core GIS functionality and PyQGIS API.
• Python 3: QGIS 3.x includes an embedded Python 3 interpreter (typically version 3.7 or higher).
• PyQt5: Required for GUI components like QDialog, QComboBox, QLineEdit, QPushButton, QLabel, QFileDialog, and QMessageBox. Bundled with QGIS 3.x installations (version 5.15.10 or similar).
• PyQGIS: Provides core QGIS functionality, including QgsProject, QgsRasterLayer, QgsMapTool, QgsMapToolIdentifyFeature, and QgsRubberBand. Included with QGIS.
• PyQt5-sip: A dependency for PyQt5, typically included with QGIS (version 12.13.0 or higher).
• Python Standard Library:
  • os: For handling file paths and folder operations.
  • glob: For matching raster filenames with user-defined patterns.

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Support and Contributions

• Homepage: https://github.com/Consortis-Geospatial
• Issue Tracker: https://github.com/Consortis-Geospatial/ImageLoader/issues
• Author: Gkaravelis Andreas - Consortis Geospatial
• Email: gkaravelis@consortis.gr
• Repository: https://github.com/Consortis-Geospatial/ImageLoader

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License

This plugin is released under the GPL-3.0 license.