Spatialite - sqlite database with spatial functions

An Open Source SpatialiteDatabase http://www.baruch.cuny.edu/geoportal/nyc_gdb/

Shapefile - plain (ooeb standard format) GIS file format invented by ESRI - Universally supported by all GIS applications - made up of three files with 1. .shp - shape format; the feature geometry itself 1. .shx - shape index format; a positional index of the feature geometry to all seeking forward and backwards 1. .dbf - attribute format; columnar attributes for each shape (dbase4 format) file extensions. If any of these files is missing/misnamed/misplaced or malformed,the whole dataset is corrupted.

Spatial SQL - exactly as standard SQL but supports data-type Geometry

Cannot directly query a Geometry value rather you use spatial functions

All Spatial functions are prefixed with ST_ but use of alias function name is allowed ST_Area() same as Area()

Geometry - abstract data type with 7 concrete sub-classes 1. Point - [x,y] 1. Linestring - simple - non-simple - closed simple - closed non-simple 1. Polygon - exterior ring no interior rings - exterior ring 1 interior ring - exterior ring 5 interior rings 1. multipoing 1. multilinestring 1. multipolygon 1. geometrycollection

WKT (Well Known Text) and WKT notations

Geometry Type WKT example POINT POINT(123.45 543.21) LINESTRING LINESTRING(100.0 200.0, 201.5 102.5, 1234.56 123.89) three vertices POLYGON POLYGON((101.23 171.82, 201.32 101.5, 215.7 201.953, 101.23 171.82)) exterior ring, no interior rings POLYGON((10 10, 20 10, 20 20, 10 20, 10 10), (13 13, 17 13, 17 17, 13 17, 13 13)) exterior ring, one interior ring MULTIPOINT MULTIPOINT(1234.56 6543.21, 1 2, 3 4, 65.21 124.78) three points MULTILINESTRING MULTILINESTRING((1 2, 3 4), (5 6, 7 8, 9 10), (11 12, 13 14)) first and last linestrings have 2 vertices each one; the second linestring has 3 vertices MULTIPOLYGON MULTIPOLYGON(((0 0,10 20,30 40,0 0),(1 1,2 2,3 3,1 1)),((100 100,110 110,120 120,100 100))) two polygons: the first one has an interior ring