Spatial Data Analysis | Mastering PostGIS

Sign In Start Free Trial

Book Overview & Buying
Table Of Contents

Mastering PostGIS

By : George Silva, Mikiewicz, Michal Mackiewicz , Nycz

1 (1)

Mastering PostGIS

1 (1)

By: George Silva, Mikiewicz, Michal Mackiewicz , Nycz

Overview of this book

PostGIS is open source extension onf PostgreSQL object-relational database system that allows GIS objects to be stored and allows querying for information and location services. The aim of this book is to help you master the functionalities offered by PostGIS- from data creation, analysis and output, to ETL and live edits. The book begins with an overview of the key concepts related to spatial database systems and how it applies to Spatial RMDS. You will learn to load different formats into your Postgres instance, investigate the spatial nature of your raster data, and finally export it using built-in functionalities or 3th party tools for backup or representational purposes. Through the course of this book, you will be presented with many examples on how to interact with the database using JavaScript and Node.js. Sample web-based applications interacting with backend PostGIS will also be presented throughout the book, so you can get comfortable with the modern ways of consuming and modifying your spatial data.

Preface

Preface

What this book covers

What you need for this book

Who this book is for

Conventions

Reader feedback

Customer support

Free Chapter

Importing Spatial Data

Importing Spatial Data

Obtaining test data

Importing flat data

Importing shape files using shp2pgsql

Importing vector data using ogr2ogr

Importing data using GIS clients

Importing OpenStreetMap data

Connecting to external data sources with foreign data wrappers

Loading rasters using raster2pgsql

Importing data with pgrestore

Summary

Spatial Data Analysis

Spatial Data Analysis

Composing and decomposing geometries

Spatial measurement

Geometry bounding boxes

Geometry simplification

Geometry validation

Intersecting geometries

Nearest feature queries

Summary

Data Processing - Vector Ops

Data Processing - Vector Ops

Primer - obtaining and importing OpenStreetMap data

Merging geometries

Slicing geometries

Buffering and offsetting geometries

Reprojecting geometries

Spatial relationships

Summary

Data Processing - Raster Ops

Data Processing - Raster Ops

Preparing data

Processing and analysis

Analytic and statistical functions

Vector to raster conversion

Raster to vector conversion

Spatial relationship

Metadata

Summary

Exporting Spatial Data

Exporting Spatial Data

Exporting data using \COPY in psql

Exporting vector data using pgsql2shp

Exporting vector data using ogr2ogr

Exporting data using GIS clients

Outputting rasters using GDAL

Outputting raster using psql

Exporting data using the PostgreSQL backup functionality

Summary

ETL Using Node.js

ETL Using Node.js

Setting up Node.js

Handshaking with a database using Node.js PgSQL client

Retrieving and processing JSON data

Geocoding address data

Consuming WFS data

Summary

PostGIS – Creating Simple WebGIS Applications

PostGIS – Creating Simple WebGIS Applications

ExtJS says Hello World

Configuring GeoServer web services

Making use of PgRaster in a simple WMS GetMap handler

Consuming WMS

Enabling CORS in Jetty

Consuming WFS in ol3

Outputting and consuming GeoJSON

Outputting and consuming TopoJSON

Implementing a simple CRUD application that demonstrates vector editing via web interfaces

Summary

PostGIS Topology

PostGIS Topology

The conceptual model

The data

Installation

Creating an empty topology

Importing Simple Feature data into topology

Inspecting and validating a topology

Accessing the topology data

Topology editing

Topology-aware simplification

Topology output

Summary

pgRouting

pgRouting

Installing the pgRouting extension

Importing routing data

pgRouting algorithms

Consuming pgRouting functionality in a web app

Summary

Geometry bounding boxes

A bounding box, often abbreviated into BBOX, is a list of the extreme coordinates of a geometry. Bounding boxes play a big role in spatial queries, as they allow for fast coarse computations; If two geometries' BBOXes do not intersect, there's no point in wasting CPU cycles for intersecting them precisely. In PostGIS, bounding boxes are computed and cached internally. There are specialized data types for bounding boxes: box2d, which can be visualized as a rectangle, and box3d, which forms, well, a box.

Accessing bounding boxes

A bounding box of a geometry can be accessed in two ways. The first is to create a Box2D type from a geometry (or a set of them):

SELECT ST_Extent(
ST_GeomFromText('POLYGON((391390 5817855,391490 5817955,391590 5818055, 319590 5817855,391390 5817855))', 32633)
);
             st_extent              
------------------------------------
 BOX(319590 5817855,391590 5818055)

Then to create one for a set of geometries:

SELECT ST_Extent(geom) FROM sometable...

Visually different images

CONTINUE READING

83

Tech Concepts

36

Programming languages

73

Tech Tools

Unlimited access to the largest independent learning library in tech of over 8,000 expert-authored tech books and videos.

Innovative learning tools, including AI book assistants, code context explainers, and text-to-speech.

50+ new titles added per month and exclusive early access to books as they are being written.

Mastering PostGIS

Search

Your notes and bookmarks