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Geospatial technologies abound, really. While consumer-grade geospatial products, like ESRI's ArcGIS for Desktop, are common throughout most economic sectors, some open source solutions do exist.

Most social media apps contain embedded geographic content, usually in the form of maps. The clue an app is "spatially enabled" is the phrase frequently seen on mobile devices: "[App Name] would like to use your current location." Some of the parent companies of the apps provide an application programming interface (API). An API provides a way of writing some code to access different parts of the app and provide a means of providing a new user experience. An example of an API being used to create a new user experience is the ability to map Tweets.

The social media passed around today contains metadata, information usually hidden from users but is necessary for the social element of communication. Knowing where a restaurant is, or a gas station is, or where your children are requires a location. Knowing where you are in relation to the restaurant or a gas station helps both parties achieve some end, eating, filling up, etc. The technology making this happen requires some spatial elements. An API helps access interesting portions of the app "metadata" and provides information useful for mapping. Some Tweets, for instance, have a geographic coordinate included. People on Twitter may also include a #hashtag. The Twitter API can help developers grab the geographic coordinate and the #hashtag, providing two essential components to create a Twitter map.

The links provided do not represent a exhaustive list of geospatial technologies. Resources include software, developer tools, and useful data.

No endorsement of any resource is implied. No support for any of the resources is offered. Users are encouraged to peruse the licensing and fair use of each site, company, organization, or agency.

Open Source GIS Software

Quantum GIS (QGIS) is a powerful and user friendly Open Source Geographic Information System (GIS) that runs on Linux, Unix, Mac OSX, Windows and Android. QGIS supports vector, raster, and database formats. QGIS is licensed under the GNU Public License.

GRASS GIS, commonly referred to as GRASS (Geographic Resources Analysis Support System), is a free and open source Geographic Information System (GIS) software suite used for geospatial data management and analysis, image processing, graphics and maps production, spatial modeling, and visualization. GRASS GIS is currently used in academic and commercial settings around the world, as well as by many governmental agencies and environmental consulting companies.

The MapWindow GIS project includes a free and open source desktop geographic information system (GIS) with an extensible plugin architecture; a GIS ActiveX control; and C# GIS programmer library called DotSpatial.

Open Source Remote Sensing Software

Within the realm of remote sensing, little is available for free. The discipline is fairly esoteric in both development and academic exposure thus the potential user community is fairly small. However, a couple options do exist. 

Quantum GIS (QGIS) is a user friendly Open Source Geographic Information System (GIS) licensed under the GNU General Public License. QGIS is an official project of the Open Source Geospatial Foundation (OSGeo). It runs on Linux, Unix, Mac OSX, Windows and Android and supports numerous vector, raster, and database formats and functionalities.

The System for Automated Geoscientific Analyses (SAGA) was developed by a team working at the University of Hamburg; Hamburg, Germany. The software grew from a need to analyze raster data, specifically digital elevation models (DEM). 

Open Source or Free Database Solutions

Besides learning some fundamental GIS / mapping skills, having some knowledge of current database software and systems can go a long way towards getting good employment. Fortunately, most database vendors see providing free tools as a way to educate, develop, and promote a sophisticated user society.

Commercial Database Software (free to develop, deploy, distribute) 

• (Microsoft)
• (IBM)
• (Oracle)

Open Source Database Software

• (The world's most popular open source database)
• (The world's most advanced open source database)
• (The world's true open source database)

Mapping APIs

Mapping APIs provide a way to access location information contained within the metadata of lots of different web sites and mobile apps. A few links below have been provided to points users in a direction. Many good tutorials exists. Finding them is about as simply as googling "geolocation" and "tutorials." 

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