GIS Scripting - Desktop GIS: Mapping the Planet with Open Source Tools - page 246

Now let's quickly test the GeoRuby install using the following script to
create a point and print it out in WKT format:

require 'rubygems'
require 'geo_ruby'
include GeoRuby::SimpleFeatures
p = Point.from_x_y(-151.25,61.75)
puts p.as_wkt

The output from the script is a whopping:

POINT(-151.25 61.75)

Although not very earth-shattering, it proves we have the environment
set up right and now can move on to doing something useful with our
PostgreSQL data and Ruby.

Remember in Section 8.2 , Importing Data, on page 122 , where we wrote
a little script to prepare the historic earthquake data for import? Well,
we're going to modify that a bit and use it to load the earthquake data
directly into PostGIS. Here's the script with the new bits added in:

Download load_earthquakes.rb

#!/usr/local/bin/ruby

Line 1

require 'rubygems'

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require 'postgres-pr/connection'

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require 'geo_ruby'

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include GeoRuby::SimpleFeatures

5

# load earthquake data into PostGIS

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conn = PostgresPR::Connection.new('gis_data',

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'gsherman',

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'',

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'tcp://madison:5432')

10

# create the database table

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conn.query('create table quake_demo (id int4 primary key, event_date date,' +

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'event_time varchar(10), latitude float, longitude float, depth float,' +

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'magnitude float, geom geometry)')

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# Open the file

15

f = File.open("db_search2291")

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# Skip the first two header records

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2.times{f.gets}

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# Member for the primary key

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key = 0

20

# process the earthquake records

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while not f.eof

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record = f.gets

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# used a fixed length approach to get the fields we want since

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# splitting on white space isn't feasible

25

event_date = record[1..10]

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event_time = record[13..22]

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latitude = record[26..32]

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