Geospatial Information Systems Made SimpleGIS FOR NON GIS DEVELOPERSDarko Boto

AGENDA

• GIS SPECIFICS

• LIBRARIES PORTS AND BINDINGS

• GDAL

• PROJ.4

• GEOS

• WHAT IS G IN GIS?

• GIS ESSENTIAL LIBRARIES

• READ TRANSFORM ANALYZE

• LIBRARY PORTS

• LIBRARY BINDINGS

• GDAL - VECTOR DATA

• GDAL - RASTER DATA

• SPATIAL INDEXES

• PROJ.4 –TRANSFORMATION

• PROJ.4 – CROATIAN SRS

• GEOS - C/C++ port of JTS

• WHAT GEOS PROVIDES?

WHAT IS G IN GIS?

Spatial data driver

Spatialcontext

Spatialoperations IS

GIS ESSENTIAL LIBRARYS

GDAL Geospatial Data Abstraction Library, C/C++ X11/MIT

PROJ4 Cartographic Projections Library, C/C++ MIT

GEOS Geometry Engine, Open Source, C/C++ LGPL

READ TRANSFORM ANALYZE

GDALREAD

SPATIAL DATA

WRITE SPATIAL DATA

PROJ4PUT DATA IN SPATIAL CONTEXT

DO SPATIAL TRANSFOR-

MATION

GEOSDO SOME SPATIAL

OPERATION

ANALYZE SPATIAL

DATA

RENDER VISUALIZE PUBLISH

Spatial data driver

Spatialcontext

Spatialoperations IS

LIBRARYS PORTS

GEOS

PROJ4

NTS

PROJ.NET

JTS

JMapProjLib

JSTS

PROJ4JS

LIBRARY BINDINGS

>>> import gdal>>> import ogr>>> import osr>>> import gdalnumeric>>> import gdalconst

• SWIG (Simplified Wrapper and Interface Generator)

• JNI (Java Native Interfaces)

Supported high-level programming languages:Python, Perl, TCL, Java, Ruby, OCaml, C#, Allegro, Lua, Common Lisp, R, Octave, Go, D, Javascript, Scilab, PHP, Scheme…

GDAL - Geospatial Data Abstraction Library

142RASTER DRIVERS

84VECTOR DRIVERS

30RASTER

UTILITIES

4VECTOR

UTILITIES

Software using GDAL:

• ESRI ArcGIS, FME, ERDAS, GoogleEarth, Mapinfo …

• PostGIS, QGIS, Geoserver, Mapnik, OTB, GRASS …

GDAL - VECTOR DATA (WKB/WKT)

Spatial databases drivers• Oracle Spatial

• SQL Server Spatial

• Postgres/PostGIS

• SQLite/Spatial…

POINT MULTIPOINT LINE MULTILINE POLYGON MULTIPOLYGON

Spatial data format drivers• Shapefile

• MID

• GML

• GeoJSON…

POINT (30 10) LINESTRING (30 10, 10 30, 40 40) POLYGON ((30 10, 40 40, 20 40, 10 20, 30 10))

SPATIAL INDEXES

QuadtreeR Tree R* Tree

GDAL - RASTER DATA

RASTERS EXAMLPES:

• DEM, DSM

• DOF

• Satelite images

• Multispectral images

GRID – dot matrix data structure

RASTER FORMATS:

• GeoTIFF

• ESRI Grid

• NetCDF

• MrSID

OPTIMIZATION:

• Tiling

• Pyramids

• Caching

COORDINATE TRANSFORMATION

• Projections

• Koordinate systems

• Transformations (on the fly)

Geoid World projections examples

CROATIAN SRS – HTRS96/TMHrvatski Terestrički Referentni Sustav / Transverse Mercator Projection

(HTRS96/TM) EPSG:3765

HTRS96/TM EPSG:3765 WGS84 EPSG:4326

GEOS - C/C++ port of JTS

SPATIAL RELATIONS:contains, within, covers,intersects, disjoint, crosses, overlaps, touches, equals

OVERLAY FUNCTIONS:intersection, difference, union, symmetric difference, unary union

Polygon overlays A intersection B A union B A diference B A symDiference B

Software using GEOS:

• GoogleEarth,

• GDAL,

• QGIS,

• PostGIS…

Provides an object model for Euclidean planar linear geometry and implements the geometry model and API

776SPATIAL

FUNCTIONS

SPATIAL ANALYSIS EXAMPLE

Map by Dr. John Snow of London, showing clusters of cholera cases in the 1854 Broad Street cholera outbreak.

WHAT GEOS PROVIDES?

Geometric functions

• Topological validity checking

• Area and Distance functions

• Overlay functions (including intersection, difference, union, symmetric difference, etc.)

• Buffer computation

• Convex hull

• Geometric simplification

• Linear referencing

• Precision reduction

• Delaunay triangulation

• Voronoi diagram generation

Spatial structures and algorithms

• Robust line segment intersection

• Efficient line arrangement intersection or noding

• Efficient point in polygon

• Spatial index structures including quadtree and STR-tree

• Planar graph structures and algorithms

I/O capabilities

• Reading and writing of WKT, WKB and GML formats

Thank you!Questions?