3. About Brian Hogg
@brianhogg WordCamp Buffalo Sep 2013 3
Software Engineering & Management
Started and sold DrawBINGO.com
Lived in Montréal, England, now Cambridge
(Ontario)
PHP/JS since 2003
4. Why Geolocation
@brianhogg WordCamp Buffalo Sep 2013 4
Events blog
Recommendations
Mapping
Store locations
… anything with content + latitude/longitude
6. Capturing the Data
@brianhogg WordCamp Buffalo Sep 2013 6
“Official” Geolocation plugin
http://wordpress.org/extend/plugins/geolocation/
WP-Geo
http://wordpress.org/extend/plugins/wp-geo/ (for
custom post types)
WordPress native apps
… other plugins / themes
Inserting a latitude and longitude for posts.
9. Capturing the Data
@brianhogg WordCamp Buffalo Sep 2013 9
Inserts a latitude and longitude for each post in the
post meta data.
http://codex.wordpress.org/Geodata
11. Capturing the Data
@brianhogg WordCamp Buffalo Sep 2013 11
Translating address string to lat/lon (geocode)
http://maps.googleapis.com/maps/api/geocode/xml?
address=Hamilton+ON&sensor=false
<geometry>
<location>
<lat>43.2500208</lat>
<lng>-79.8660914</lng>
</location>
<location_type>APPROXIMATE</location_type>
</geometry>
12. Using the Data
@brianhogg WordCamp Buffalo Sep 2013 12
Simple front-end pop-up
Using WP_Query (meta_query)
Hooks to store in separate, indexed table
Custom feeds
…
14. Using the Data
@brianhogg WordCamp Buffalo Sep 2013 14
Database query
Get location of user
Restrict posts using a “bounding box”
Ordering by distance from a lat/lon
21. Using the Data
@brianhogg WordCamp Buffalo Sep 2013 21
SELECT SQL_CALC_FOUND_ROWS wp_posts.ID FROM wp_posts INNER JOIN
wp_postmeta ON (wp_posts.ID = wp_postmeta.post_id) INNER JOIN
wp_postmeta AS mt1 ON (wp_posts.ID = mt1.post_id) LEFT JOIN
wp_geo geo ON wp_posts.ID = geo.post_id WHERE 1=1 AND
wp_posts.post_type = 'post' AND (wp_posts.post_status =
'publish' OR wp_posts.post_status = 'private') AND
( (wp_postmeta.meta_key = 'geo_latitude' AND
CAST(wp_postmeta.meta_value AS DECIMAL) BETWEEN '42' AND '43')
AND (mt1.meta_key = 'geo_longitude' AND CAST(mt1.meta_value AS
DECIMAL) BETWEEN '-79.9999' AND '-78') ) GROUP BY wp_posts.ID
ORDER BY wp_posts.post_date DESC LIMIT 0, 15
Sample WP_Query SQL (bounding box)
22. Using the Data
@brianhogg WordCamp Buffalo Sep 2013 22
WP_Query method very inefficient especially with
larger amounts of data
Separate table can be used with an index,
numeric data format
23. Using the Data
@brianhogg WordCamp Buffalo Sep 2013 23
Create a new indexed table in the database
Create a WP hook to store in the new table
CREATE TABLE IF NOT EXISTS `wp_geo` (
`post_id` bigint(20) unsigned NOT NULL,
`lat` float NOT NULL,
`lon` float NOT NULL,
PRIMARY KEY (`post_id`),
KEY `latlon` (`lat`,`lon`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
Not really the mapping side, but storing and using the data and making it easy for end-user to maintain… can talk after
… but relatively new to Wordpress
There are limits to how many times you can call this per day, API key, etc
pre_get_posts
URL of theory there (Java code example) – “GREAT CIRCLE” approximation/projection -- Any mistakes? Let me know
Template tag or something.. -- IF ALREADY HAVE POSTS - Problem with sorting on PHP side – 1000’s of records, getting just one page? Have to sort all of them each time --- especially if no distance.
Create a hook on activation of the plugin, and to import existing post meta values… 2) can drop on deactivation, too
Other conditions to save geolocation can add… Assumes post meta data is already saved, works alright if only using the WP UI, otherwise need to use updated_post_meta
Don’t have to add the WHERE necessarily – and COULD just use $wpdb and a custom query depending on where you’ll be using the data
LIMIT and other clauses stay the same, so integrates into existing site / feed
Could do something as simple as an is_admin() check --- return $clauses !!! If this is FALSE (Mo)
CUSTOM FEED “CACHING” – clear your browser! /// Google Maps API, Open Street Map (open source alternative)
Don’t even necessarily need a front-end website – easy way for clients to maintain the geographic data (WP posts)
Geo data store --- one meta key, but gives the idea
