GIS is important since it gives us the instruments important to answer complex geospatial questions. It incorporates spatial and tabular data in a single consistent framework and it gives knowledge into examples and spatial connections inside information that is not evident outside of a GIS.
To display an accurate visual representation of a location, a GIS uses an absolute location reference system. Latitude and longitude, written in degrees (°), is one such system.
Latitude lines, known as parallels, run horizontally, and measure the distance north or south of the Equator. The Equator is the starting point of measuring latitude and is 0° latitude. Latitude is measured in degrees from 0° to 90° and is specified as North or South.
Longitude lines run vertically and are known as meridians. They indicate the distance east or west of the "prime meridian." The prime meridian runs through Greenwich, England and is 0° longitude.
There are many sources for geospatial information and data. The US federal government has created a portal known as the Geo.Data.gov(http://geo.data.gov/), part of Data.gov, to promote communication and sharing of geographic data by all levels of government and the public. GIS data are also available at the state and local government levels, from commercial vendors, and from other organizations.
Some sources of GIS data include:
- Geo.Data.gov - http://geo.data.gov/
- US Census Bureau - http://www.census.gov/geo/www/index.html
- US Census Bureau State & County QuickFacts- http://quickfacts.census.gov/qfd/index.html
- The National Map - http://nationalmap.gov/
- National Aeronautics and Space Administration (NASA) - http://www.nasa.gov/home/index.html
- EPA National Geospatial Program - http://www.epa.gov/geospatial/
- Federal Emergency Management Agency (FEMA) - http://gis.fema.gov/
- National Geodetic Survey - http://www.ngs.noaa.gov/
- National Cancer Institute - http://seer.cancer.gov/
- Center for Applied Research and Environmental Systems (CARES)(http://www.cares.missouri.edu/), University of Missouri at Columbia
Metadata is a data that describes other data. It provides additional information about the data that the GIS uses, which is not included in the data itself (e.g. date of origination).
PhilGIS offers free downloadable geospatial data about the Philippines.
GIS, which means Geographic Information System or Geographical Information System, is a system designed to capture, analyze, store and manipulate data. Also, it lets us comprehend data and enables us to present all its types to further understand its relationship, patterns and trend be it in a spatial or geographical form.
Importing/Exporting (File Treatment)
Shapefile (.shp) is a file extension used in Geographical Information Systems. SHP is short for "shape." Other file extension includes (.shp, .shx, .dbf)
Tagged Image File Format (.tif/.tiff) is a flexible format that can be lossless or lossy.
JPEG File Interchange Format (.jfif) is a standard image format. It solves some of JIF's limitations in regard to simple JPEG encoded file interchange.
Joint Photographic Experts Group (.jpeg), a format for compressing images, is a commonly used method of lossy compression for digital images, particularly for those images produced by digital photography.
1. ESRI shape file format are available with Federal Geographic Data Committee (FGDC) compliant metadata.
2. JPEG File Interchange Format (.jfif) is a standard image format. It solves some of JIF's limitations in regard to simple JPEG encoded file interchange.
3. Tagged Image File Format (.tif/.tiff) is a flexible format that can be lossless or lossy.
4. Joint Photographic Experts Group (.jpeg), a format for compressing images, is a commonly used method of lossy compression for digital images, particularly for those images produced by digital photography.
Quantum GIS, DIVA GIS, SAGA GIS, ILWIS, MultiSpec, GIS Data Viewers, ArcGIS Explorer, Free GIS Software Programs and Related Tools, ForestPal and DEM Processing.