Transfer format between geodatabase and OpenLayers - php

Question

I was curious ab your opinions whats the most efficient transfer format between SpatiaLite and OpenLayers. Currently Im developing an application based on SpatiaLite (extension of SQLite) and OpenLayers and as a transfer format I use GeoJSON.
My procedure:
1) quering DB by php script, using SpatiaLite's function AsGeoJSON, thus obtaining geojson formatted data
2) using php's print() to transfer retrieved data from php variable to JS variable:
$result = $db->query($query);
$r = '{"type": "FeatureCollection","features": [';
while($row = $result->fetchArray(SQLITE3_ASSOC))
{
$r .= '{"type":"Feature","properties":{}, "geometry":' . $row['geometry'] . '},';
}
$r .= ']}';
print'<script> CadastreBorder = ' . $r . '; </script>';
3) creating the features for Vector Layer in OpenLayers by reading
var vectorLayer = new OpenLayers.Layer.Vector(name, {style: style, rendererOptions:
{zIndexing: true}});
var formatGeoJSON = new OpenLayers.Format.GeoJSON({});
vectorLayer.addFeatures(formatGeoJSON.read(CadastreBorder));
map.addLayer(vectorLayer);
Is there any way how to achieve the same goal more efficiently and more nicely?
Thanks!

Answer 1

Not sure about speed, but if you're using recent version of PHP (5.2 >=) you'd might consider using json_encode on php's arrays. Instead of creating string you'd create an array looking somewhere like this:
$geoJSON_array = Array(
"type" => "FeatureCollection",
"features" => Array()
);
And for each row of geometry, add new table to "features":
Array(
"type" => "Feature",
"properties" => Array(),
"geometry" => Array(... your geometry),
)
After creating such array, run json_encode over it and you're home. For safety I'd check it validates (e.g. using http://geojsonlint.com/). This may help you later on, when e.g. there would be need to support new information, or to add new kinds of elements to the map.
Question: Why are you not using fixed strategy for loading points? If you're creating this geoJSON to file/as script, you may also tell openlayers to download it automatically, likes this:
var vectorLayer = new OpenLayers.Layer.Vector(name, {
strategies: [new OpenLayers.Strategy.Fixed()],
protocol: new OpenLayers.Protocol.HTTP({
url: "json/my_geojson.json",
format: new OpenLayers.Format.GeoJSON()
}),
style: style,
rendererOptions: {zIndexing: true}
});