What are some open source remote sensing software packages?
There has been a big shift over the years to build software in an open, collaborative manner. This software is made available to the public and is called open source. There is no exception for open source remote sensing software. Satellite and aerial imagery provides answers for environmental change, weather forecasting, disaster management, food security and other remote sensing applications. Remote sensing software processes images and provides solutions to local or global issues. In an open source environment, useful remote sensing techniques can be performed such as filtering data, performing classification and even radar decomposition.

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A list of open source remote sensing software.
The choices for commercial remote sensing software has increased over the years. Vector and raster data are both integral parts in GIS software. But what you may not know is the abundance of choice for open source remote sensing software. The big plus is: they are for public use at no cost. We’ll walk you through what each one can bring to the table in this list of 10 open source remote sensing software packages.

1. SAGA GIS: System for Automated Geoscientific Analyses
SAGA GIS is on the top of the list and for good reason. The main reason being: SAGA GIS is ideal for most GIS and remote sensing needs.
A rich library of modules gives SAGA GIS a big advantage. These modules come in the form of raster analyses and manipulation.
What gives SAGA GIS a kick is its quick and reliable raster processing. Read More: SAGA GIS (System for Automated Geoscientific Analyses) Review and Guide.

2. Opticks
Opticks might be that magic bullet that you’re looking for in open source remote sensing software.
The neat part about this software is the long list of extensions you can add. There are plugins for raster math, radar processing and hyper/multispectral. Now, that is a lot functionality for open source remote sensing software. Make sure to check the compatibility before downloading an extension though. You might have to scale back your Opticks version in order for the extension to work properly.

3. GRASS: Geographic Resources Analysis Support System
GRASS may be the most popular software package on this list. And for good reason.
GRASS is full of functionality: image classification, PCA, edge detection, radiometric corrections, 3D, geostatistics analysis and filtering options. Another key feature of GRASS is the LiDAR processing and analysis. You can filter LiDAR points, create contours and generate DEMs. Next time you see a LAS file, see what GRASS can do with it.

4. PolSARPro
For synthetic aperture radar, you may want to take a nice, long look at PolSARPro.
This software can handle dual and full polarization SAR data. The SAR data can come from ENVISAT-ASAR, ALOS-PALSAR, RADARSAT-2 and TerraSAR-X. There’s a wide range of tools like importing, conversion, filtering, decompositions, inSAR processing and calibration.
Another neat part of this software is the graph processing framework where users can automate workflow. This functionality is similar to ArcGIS model builder and easy to set up. Overall, PolSARPro is a very sophisticated piece of open source remote sensing software. You need to take a look at PolSARPro if you’re working with full or dual polarization SAR data.

5. ORFEO: Optical and Radar Federated Earth Observation
The ORFEO toolbox was a cooperative project developed by France and Italy.
It is a library of remote sensing image processing specifically aimed at high spatial resolution. ORFEO provides a wide range of remote sensing functions: radiometry, PCA, change detection, pan sharpening, image segmentation, classification and filtering. One really interesting aspect of this software is the capability to do object based image analysis. This is a rare feature seen in software nowadays.

6. OSSIM: Open Source Software Image Map
OSSIM is a high performance open source remote sensing software application. It has been actively developed for almost two decades. Interesting enough, it’s being funded through US departments such as in intelligence and defense. Some of the key features is compatibility with more than 100 raster and vector formats and over 4000 different projections and datums. It supports a long list of sensors but some may require additional plug-ins. If you need some remote sensing direction for high spatial resolution imagery, OSSIM might be the answer you have been searching for.

7. InterImage
InterImage is a bit different from the other open source remote sensing software on this list. It specializes in automatic image interpretation, which is pretty neat. The core theme of automatic image interpretation is object-based classification (OBIA). This involves segmentation, exploring attributes and supervised classification. Although developed in Brazil, documentation is available in English.

8. E-foto
E-foto is concerned with mainly one thing: digital photogrammetry.
The core functionality of this open source remote sensing software is photo triangulation, stereoscopic modeling, digital elevation model extraction and terrain correction. This software provides a fully functional photogrammetry tool set to use at no cost. E-foto has loads of tutorials and examples to get you well on your way to being a photogrammetry expert.

9. ILWIS: Integrated Land and Water Information System
ILWIS has been around for more than 25 years. It has had over 27,000 downloads since its first release. It wasn’t until recently that it has become available for public use. ILWIS was originally built for researchers and students. For this reason, effort was concentrated on developing a user-friendly environment. The other main focus was compatibility with raster and vector formats. This has been done by full integration with the GDAL library. The practical uses of ILWIS makes it a prime choice for remote sensing activities.

10. gvSIG
gvSIG is known for its wide variety of rich features. But there’s more to it than just that. gvSIG is full of incredible capabilities: supervised classification, defining ROIs, band algebra and decision trees. gvSIG stands for Generalitat Valenciana Geographic Information System. Generalitat Valenciana is the Spanish regional authority the system was designed for. I bet you didn’t know that.

Quantum GIS (QGIS) is one of the most powerful open source GIS software packages available for free. This software package allows users to visualize, analyze, interpret and understand spatial data.
Plugins are the key to QGIS success. Raster manipulation includes neighborhood analysis, map algebra, surface interpolation, hydrologic modelling and terrain analysis like slope and aspect. There are plugins for semi-automated classification, BEAM and NEST framework, multitemporal raster analysis, viewshed analysis and much more.
What more can you ask for?
Read More: Open Source QGIS Guide and Review

Most of us think we have to spend hundreds of dollars on remote sensing software. Thankfully, this is just not true anymore. This collection of 10 free open source remote sensing software packages is invaluable to process remote sensing data without breaking the bank.
Choice is good. Yes, no, maybe?
It’s not such a bad thing if you have too many open source choices for a remote sensing problem. This open source remote sensing software list encompasses a wide range of disciplines: photogrammetry, OBIA, LiDAR, SAR and more.
GIS and remote sensing software are both part of what some people call the “open source movement“. It’s satisfying to know that the big commercial brands are not everything that’s out there. These remote sensing software packages can deliver just as much punch.