Mapping and GIS Lessons for Poets, Historians, and Scientists: Introduction: Cartography and GIS

Besides the extensive use of maps in day to day life, maps are very important in the academic world. Here is a sample of fields in which geospatial technologies can be used:

Environmental sciences, Archaeology, Social sciences, Law enforcement, Military, Epidemiology, Urban planning, Marketing, Literature, History, Classics, Chemistry, Mathematics, etc. 

Things to do with GIS:

• Identify patterns and retrieve information from maps
• Count, group, classify, reclassify, isolate, measure and quantify map features
• Overlay maps to compare features and create new maps
• Visualize, interpolate, slice, cross-section, sample and generalize surfaces
• Identify the shortest or fastest travel path between points
• Perform topographic and other feature analyses

KML: Keyhole Markup Language

KML is a file format used to display geographic data in an Earth browser such as Google Earth. KML uses a tag-based structure with nested elements and attributes and is based on the XML standard. All tags are case-sensitive and must appear exactly as they are listed in the KML Reference. The Reference indicates which tags are optional. Within a given element, tags must appear in the order shown in the Reference.

Map Design Elements

Scale bar: a graphical device used to represent map scale

North arrow: is a graphical device on a map used to show the orientation of the map

Legend: graphical device found on a map that explains the meaning of symbols and colors found on a map.  

Categories of Maps

• A reference map is a map that serves to show the location of features, examples include zoning maps, topographic maps, and street maps.
• A thematic map is designed to convey information pertaining to a specific theme or feature (population, cultural lifestyle, etc.) or phenomena (rainfall, etc.) connected with a geographic area.
• A choropleth map is a kind of thematic map where data is displayed in discrete categories. Its geographic regions are colored, shaded, or patterned in relation to a value.

A key word to GIS technology is Geography – this means that some portion of a map's data is spatial (referenced to locations).

Another type of data on digital maps is "attribute data."  Attribute data gives additional information about each spatial feature. 

Both geographic and attribute data can be expressed in tables, such as a CSV table in Microsoft Excel. 

Vector data

• Represented as either points, lines, or polygons. 
• Best for discrete or thematic data.Data with an exact location or hard boundaries.
• Examples: county boundaries, the location of roads and railroads using lines, or point data indicating the location of fire hydrants. 

​Raster data:

• Continuous data, or information without hard boundaries or locations. 
• viewed as a series of grid cells : each cell has a value representing the feature being observed. 
• appropriate for modeling surfaces: elevation, temperature, precipitation. 
• Also includes remote sensing imagery, like aerial photography and satellite imagery.