imview

Image viewers for geospatial data

Overview

This repo contains several utilities that I use on a daily basis for rapid data preview, detailed analysis, and figure generation. The imviewer.py tool is probably the most useful. It works well, but could use a rewrite, as it has been glommed together over the span of 4-5 years.

Viewers

• imviewer - viewer for geospatial data, overlay capabilities
• stack_view - viewer for "stack.npz" time series output (see pygeotools), allowing for point sampling and plotting
• iv - lightweight viewer for standard images (jpg, png, etc.)
• review_img - lightweight viewer to identify good and bad images

Modules

• lib/pltlib - a collection of useful functions for matplotlib plotting, including drawing vector data over raster data

Command-line Examples

Preprocessing (optional):

mos_fn=BigDEM.tif
gdaldem hillshade $mos_fn ${mos_fn}_hs_az315.tif
gdaladdo -ro -r average --config COMPRESS_OVERVIEW LZW --config BIGTIFF_OVERVIEW YES $mos_fn 2 4 8 16 32 64
gdaladdo -ro -r average --config COMPRESS_OVERVIEW LZW --config BIGTIFF_OVERVIEW YES ${mos_fn}_hs_az315.tif 2 4 8 16 32 64

View color DEM overlaid on shaded relief map:

imviewer.py $mos_fn -overlay ${mos_fn}_hs_az315.tif -label 'Elevation (m WGS84)'

• By default, this will quickly load a low-resolution preview (specify -full to load full-res image)
• Lower right corner shows coordinates and value under cursor
• Left-click to sample image coordinates, map coordinates and raster value
• Can specify transparency with -alpha 0.5

View with user-defined color map and limits

imviewer.py -cmap 'RdYlBl' -clim -5 5 dem_dz_eul.tif -label 'Elevation difference (m)'

Link several images (allows for simultaneous zoom and pan):

imviewer.py -link dem.tif image.tif velocity.tif

View polyline shapefile overlay:

imviewer.py $mos_fn -overlay ${mos_fn}_hs_az315.tif -shp polyline.shp

Output high-quality figure with scalebar:

imviewer.py $mos_fn -overlay ${mos_fn}_hs_az315.tif -scale x -label 'Elevation (m WGS84)' -of png -dpi 300

View time series stack:

make_stack.py -tr 'mean' -te 'intersection' 20080101_dem.tif 20090101_dem.tif 20100101_dem.tif
stack_view.py 20080101_dem_20100101_dem_stack_3.npz

• Left-click to extract time series at point on any of the context maps
• Right-click to clear all points
• Can zoom and pan on context maps

Installation

Install the latest release from PyPI:

pip install imview 

Note: by default, this will deploy executable scripts in /usr/local/bin

Building from source

Clone the repository and install:

git clone https://github.com/dshean/imview.git
pip install -e imview

The -e flag ("editable mode", setuptools "develop mode") will allow you to modify source code and immediately see changes.

Core requirements

• Matplotlib
• GDAL/OGR
• NumPy
• pygeotools

License

This project is licensed under the terms of the MIT License.