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Notes for learning the very basics of GIS - refrence of texts and online resources at the end of this Markdown file

Most of these basic definitions are historic and archaic in nature - unless explicitly stated. These notes are being collated as a matter of pedagogy about the historic perspective of GIS in general.

  • GIS - Geographic Information Systems (GIS)

  • GNSS - Global navigation satellite system (GNSS)

  • Map Server - A map server can broadly be defined as a software platform for dynamically generating spatially referenced (digital) map products from geospatial data.

  • Remote Sensing using supervised and unsupervised classification of raster data.

  • Subset - A subset or range query is a common operation where a user-defined region of interest (ROI) portion of the dataset is returned (as a map) to the user.

  • Overlay - This is another typical query, where a composite map is generated by overlying the user-selected spatial data layers. A subset operation can be combined with an overlay to generate a composite map of a given ROI.

  • Spatial queries are point and range queries. In a point query, a spatial object is selected based on the user-selected point location (or within a small rectangle about that point); on the other hand, a range query returns all spatial objects within the ROI.

  • GRASS - Geographic Resources Analysis Support System (GRASS).

  • Client Server Arch - Plug-ins have the advantage that they can access local data, whereas applets have restricted access to resources on both the client and the server for security reasons. MapServer University of Minnesota Pg: 942

  • WMS - Web Map Server

  • WMS functions read the .map file to produce content matching the user’s WMS request. Any standard browser (or client system) can query a WMS-compliant server for one or more of the following services: map images (GetMap), service-level metadata (GetCapabilities), and, optionally, information about particular features (GetFeatureInfo). These requests are submitted to the server in the form of URLs.

  • CGI scripts - Common Gateway Interface . Used to provide intelligence to server when Client sends a Formatted URL. [ Check Further ]

  • GDAL – Geospatial Data Abstraction Library

  • XML/GML and MapServer. Extensible markup language (XML) is fast becoming the standard for data exchange between web applications. HTML and XML are both subsets of Standard Generalized Markup Language(SGML). However, there is a subtle difference between HTML and XML.

  • HTML tags serve the purpose of describing how the data items should be displayed, while XML tags describe the data itself. This difference is very important; the self-describing nature of XML allows programs to interpret the data in XML documents. Interpretation of data stored in XML documents is possible due to the existence of Document Type Definitions (DTDs) or XML schema.

  • GML or GMLv3 - GML is an XML encoding for transport and storage of geographic information which includes both the geometry and properties of geographic features. Geography Markup Language v3 . This specification is more suitable for vector data exchange between WebGISs. Whats about RASTER Data [ Check Further ]

  • GML provides support for the geometry elements to the corresponding Point, Linestring, LinearRing, Polygon, MultiPoint, MultiLineString, MultiPolygon, and GeometryCollections. It also provides a coordinate element for encoding coordinates and a box element for defining spatial extents.

  • A WCS-Web Coverage Service -- enabled server provides access to potentially detailed and rich sets of geospatial information. As opposed to the WMS server, which filters and generates data products in the form of static maps, the WCS server actually generates data products that meet user-defined criteria in specific (well-known) formats that can be consumed by the client-side software (e.g., ARC/INFO, Imagine, MATLAB, IDL). The WCS specification provides the following three operations: GetCapabilities, GetCoverage, and DescribeCoverage.

  • The Minnesota Department of Natural Resources GIS Data Deli

  • Fishing Maps by Angling Technologies

  • TIGER - Topologically Integrated Geographic Encoding and Referencing system

  • Natural Resource Analysis and Mapping System (NRAMS)

  • SEA-COOS Ocean Observations (http://nautilus.baruch.sc.edu/portal_rs/)

  • Normalized difference vegetation index (NDVI) -

QGIS

Pedagogy Notes specific to QGIS - these have been collated from various historic sources and not guaranteed to be upto date / current , for current updates kindly refer the QGIS user Guide - https://docs.qgis.org/2.18/pdf/en/QGIS-2.18-UserGuide-en.pdf :-

  • QGIS Spatial Bookmarks -

  • Attribute Table

  • Vector Symbolization

  • Project File. All the settings in a session can be stored in an XML-based project file. QGIS does not use a native format to store the data sources on disk. Instead it uses the external data formats and stores references to them in the project file.

QGIS Plugins :-