Broaden your selection:
- On a stationary GPS without a differential correction signal, you should see a 20 meter average radius "random walk" pattern. On the same receiver with DGPS corrections and a good view of the sky, the error should be reduced to approx. 2 meters average radius.
- Earth3D visualizes the earth in realtime in a 3D view. You can rotate and zoom the view until countries, cities and even single houses become visible (in areas where the necessary map resolution is available), and fly around. You can also embed external data like current earthquake positions or cloud data. Additional data layers can be added to the view, e.g. country flags and names. The package uses data from NASA, USGS, the CIA, and the city of OsnabrÃÂ¼ck. The data is loaded on demand over the Internet.
- The Geospatial Data Abstraction Library (GDAL) is a unifying C/C++ API for accessing raster geospatial data, and currently includes formats like GeoTIFF, Erdas Imagine, Arc/Info Binary, CEOS, DTED, GXF, and SDTS. It is intended to provide efficient access, suitable for use in viewer applications, and also attempts to preserve coordinate systems and metadata. Python, C, and C++ interfaces are available.
- 'GEOS' is a C++ implementation of the functions and predicates defined in the OpenGIS "Simple Features for SQL" specification. It includes high quality implementations of all important spatial relationships and operations, robust versions of all functions in the dimensionally extended 9 intersection predicate model, and implementations of the operators Buffer(), Union(), and Intersection() and all other SFSQL functions including Area(), Length(), Centroid(), etc.
- Generic Mapping Tools is a collection of ~60 GNU/Linux tools that allow users to manipulate (x,y) and (x,y,z) data sets (including filtering, trend fitting, gridding, projecting, etc.) to produce Encapsulated PostScript File (EPS) illustrations ranging from simple x-y plots through contour maps to artificially illuminated surfaces and 3-D perspective views in black and white, gray tone, hachure patterns, and 24-bit color. GMT supports 25 common map projections plus linear, log, and power scaling, and comes with support data such as coastlines, rivers, and political boundaries. Since the package is quite large, the authors suggest looking at the list of mirrors on the page to ensure that you download from the one closest to you.
- 'GPSBabel' converts waypoint data between about four dozen file formats, including Magelland and Garmin serial, Mapsource, Mapsend, Streets & Trips, Delorme, National Geographics, many Pal formats, and many others. It is endian and word-size safe, includes a GUI, and runs on a variety of operating systems. It also supports Groundspeak GPX extensions for geocaching.
- 'GPSTk' is a set of both fundamental and advanced GPS processing algorithms. The library provides functions including RINEX I/O, ephemeris calculation, atmospheric refraction models, and positioning algorithms. The applications include cycle slip detection and removal, calculation of the Total Electron Content (TEC) of the ionosphere, bindings to 'octave', and RINEX file manipulation.
- GRASS (Geographic Resources Analysis Support System)
- Commonly referred to as GRASS, this is free Geographic Information System (GIS) software used for geospatial data management and analysis, image processing, graphics/maps production, spatial modeling, and visualization. GRASS is currently used in academic and commercial settings around the world, as well as by many governmental agencies and environmental consulting companies. GRASS is an official project of the Open Source Geospatial Foundation. GRASS contains modules for raster data manipulation (2D and 3D voxels), vector data manipulation, rendering images on the monitor or paper, multispectral image processing, point data management and general data management, as well as tools for interfacing with digitizers, scanners, and SQL databases as PostgreSQL, and other through an ODBC interface.
- GNU Gama is a project dedicated to adjustment of 'geodetic networks'. GNU Gama is based on a C++ library of geodetic classes and functions `libgama' and a small C++ template matrix library `matvec'. The stable branch of the project is limited to network adjustment in a local coordinate system and its functionality is represented by the program `gama-local, ' which adjusts geodetic (free) networks of observed distances, directions, angles, height differences, 3D vectors and observed coordinates (coordinates with given variance-covariance matrix). In the new branch the adjustment model is based on geocentric coordinate system (adjustment model on ellipsoid). Its functionality is represented by the program `gama-g3'.
- Geo Weather
- Geo::Weather is a Perl module used to retrieve weather.com information based on city/state or US zip code. In order for the timeout code to work correctly, you must be using a recent version of libwww-perl and IO::Socket. Geo::Weather was developed with libwww-perl 5.53 and IO::Socket 1.26.