PHP - Need Help With Database Query (i Think?) Wordpress

<?php
if ( !class_exists( 'SM_XML_Search' ) ){
	class SM_XML_Search{
		// Register hook to perform the search
		function sm_xml_search() {
			add_action( 'template_redirect', array( &$this, 'init_search' ) );
		}

		// Inits the search process. Collects default options, search options, and queries DB
		function init_search() {
			if ( isset( $_GET['sm-xml-search'] ) ) {
				global $wpdb, $simple_map;
				remove_filter( 'the_title', 'at_title_check' );

				$defaults = array(
					'lat' => false,
					'lng' => false,
					'radius' => false,
					'namequery' => false,
					'query_type' => 'distance',
					'address' => false,
					'city' => false,
					'state' => false,
					'zip' => false,
					'onlyzip' => false,
					'country' => false,
					'limit' => false,
					'pid'	=> 0,
				);
				$input = array_filter( array_intersect_key( $_GET, $defaults ) ) + $defaults;

				$smtaxes = array();
				if ( $taxonomies = get_object_taxonomies( 'sm-location' ) ) {
					foreach ( $taxonomies as $key => $tax ) {
						$phpsafe = str_replace( '-', '_', $tax );
						$_GET += array( $phpsafe => '' );
						$smtaxes[$tax] = $_GET[$phpsafe];
					}
				}

				// Define my empty strings
				$distance_select = $distance_having = $distance_order = '';

				// We're going to do a hard limit to 500 for now.
				if ( !$input['limit'] || $input['limit'] > 500 )
					$limit = "LIMIT 500";
				else
					$limit = 'LIMIT ' . absint( $input['limit'] );

				$limit = apply_filters( 'sm-xml-search-limit', $limit );

				// Locations within specific distance or just get them all?
				$distance_select = $wpdb->prepare( "( 3959 * ACOS( COS( RADIANS(%s) ) * COS( RADIANS( lat_tbl.meta_value ) ) * COS( RADIANS( lng_tbl.meta_value ) - RADIANS(%s) ) + SIN( RADIANS(%s) ) * SIN( RADIANS( lat_tbl.meta_value ) ) ) ) AS distance", $input['lat'], $input['lng'], $input['lat'] ) . ', ';
				$distance_order = 'distance, ';

				if ( $input['radius'] ) {
					$input['radius'] = ( $input['radius'] < 1 ) ? 1 : $input['radius'];
					$distance_having = $wpdb->prepare( "HAVING distance < %d", $input['radius'] );
				}

				$i = 1;
				$taxonomy_join = '';
				foreach ( array_filter( $smtaxes ) as $taxonomy => $tax_value ) {
					$term_ids = explode( ',', $tax_value );
					if ( $term_ids[0] == 'OR' ) {
						unset( $term_ids[0] );
						if ( empty( $term_ids ) ) {
							continue;
						}
						$search_values = array( "IN (" . vsprintf( '%d' . str_repeat( ',%d', count( $term_ids ) - 1 ), $term_ids ) . ")" );
					} else {
						$search_values = array();
						foreach ( $term_ids as $term_id ) {
							$search_values[] = sprintf( '= %d', $term_id );
						}
					}
					foreach ( $search_values as $search_value ) {
						$taxonomy_join .= "
							INNER JOIN
								$wpdb->term_relationships AS term_rel_$i ON posts.ID = term_rel_$i.object_id
							INNER JOIN
								$wpdb->term_taxonomy AS tax_$i ON
									term_rel_$i.term_taxonomy_id = tax_$i.term_taxonomy_id
									AND tax_$i.taxonomy = '$taxonomy'
									AND tax_$i.term_id $search_value
						";
						$i++;
					}
				}

				$sql = "SELECT
						lat_tbl.meta_value AS lat,
						lng_tbl.meta_value AS lng,
						$distance_select
						posts.ID,
						posts.post_content,
						posts.post_title
					FROM
						$wpdb->posts AS posts
					INNER JOIN
						$wpdb->postmeta lat_tbl ON lat_tbl.post_id = posts.ID AND lat_tbl.meta_key = 'location_lat'
					INNER JOIN
						$wpdb->postmeta lng_tbl ON lng_tbl.post_id = posts.ID AND lng_tbl.meta_key = 'location_lng'
						$taxonomy_join
					WHERE
						posts.post_type = 'sm-location'
						AND posts.post_status = 'publish'
					GROUP BY
						posts.ID
						$distance_having
					ORDER BY " . apply_filters( 'sm-location-sort-order', $distance_order . ' posts.post_name ASC', $input ) . " " . $limit;

				$sql = apply_filters( 'sm-xml-search-locations-sql', $sql );

				// TODO: Consider using this to generate the marker node attributes in print_xml().
				$location_field_map = array(
					'location_address' => 'address',
					'location_address2' => 'address2',
					'location_city' => 'city',
					'location_state' => 'state',
					'location_zip' => 'zip',
					'location_country' => 'country',
					'location_phone' => 'phone',
					'location_fax' => 'fax',
					'location_email' => 'email',
					'location_url' => 'url',
					'location_special' => 'special',
				);

				$options = $simple_map->get_options();
				$show_permalink = !empty( $options['enable_permalinks'] );

				if ( $locations = $wpdb->get_results( $sql ) ) {
					// Start looping through all locations i found in the radius
					foreach ( $locations as $key => $value ) {
						// Add postmeta data to location
						$custom_fields = get_post_custom( $value->ID );
						foreach ( $location_field_map as $key => $field ) {
							if ( isset( $custom_fields[$key][0] ) ) {
								$value->$field = $custom_fields[$key][0];
							}
							else {
								$value->$field = '';
							}
						}

						$value->postid = $value->ID;
						$value->name = apply_filters( 'the_title', $value->post_title );

						$the_content = trim( $value->post_content );
						if ( !empty( $the_content ) ) {
							$the_content = apply_filters( 'the_content', $the_content );
						}
						$value->description = $the_content;

						$value->permalink = '';
						if ( $show_permalink ) {
							$value->permalink = get_permalink( $value->ID );
							$value->permalink = apply_filters( 'the_permalink', $value->permalink );
						}

						// List all terms for all taxonomies for this post
						$value->taxes = array();
						foreach ( $smtaxes as $taxonomy => $tax_value ) {
							$phpsafe_tax = str_replace( '-', '_', $taxonomy );
							$local_tax_names = '';

							// Get all taxes for this post
							if ( $local_taxes = wp_get_object_terms( $value->ID, $taxonomy, array( 'fields' => 'names' ) ) ) {
								$local_tax_names = implode( ', ', $local_taxes );
							}

							$value->taxes[$phpsafe_tax] = $local_tax_names;
						}
					}
				} else {
					// Print empty XML
					$locations = array();
				}

				$locations = apply_filters( 'sm-xml-search-locations', $locations );
				$this->print_json( $locations, $smtaxes );
			}
		}

		// Prints the JSON output
		function print_json( $dataset, $smtaxes ) {
			header( 'Status: 200 OK', false, 200 );
			header( 'Content-type: application/json' );
			do_action( 'sm-xml-search-headers' );

			do_action( 'sm-print-json', $dataset, $smtaxes );

			echo json_encode( $dataset );
			die();
		}
	}
}