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Aggregation: Extract the query to get the grid data

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This commit is contained in:
Raul Marin 2019-07-04 17:15:53 +02:00
parent 892479d9b9
commit 8454eef6e9
1 changed files with 22 additions and 14 deletions
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36
lib/cartodb/models/aggregation/aggregation-query.js
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@ -300,7 +300,7 @@ const havingClause = ctx => {
// We limit the the minimum resolution to avoid division by zero problems. The limit used is
// the pixel size of zoom level 30 (i.e. 1/2*(30+8) of the full earth web-mercator extent), which is about 0.15 mm.
//
// NOTE: We'd rather use !pixel_height!, but in Mapnik this value is extent / 256 for raster
// NOTE: We'd rather use !scale_denominator!, but in Mapnik this value is extent / 256 for raster
// and extent / tile_extent {4096 default} for MVT, so since aggregations are always based
// on 256 we can't have the same query in both cases
// As this scale change doesn't happen in !scale_denominator! we use that instead
@ -309,6 +309,26 @@ const gridResolution = ctx => {
return `${256/ctx.res} * GREATEST(!scale_denominator! * 0.00028, ${minimumResolution})::double precision`;
};
// SQL query to extra the boundaries of the area to be aggregated and the grid resolution
const gridInfoQuery = ctx => {
return `
SELECT
res,
CEIL (ST_XMIN(cdb_full_bbox) / res) * res AS cdb_xmin,
FLOOR(ST_XMAX(cdb_full_bbox) / res) * res AS cdb_xmax,
CEIL (ST_YMIN(cdb_full_bbox) / res) * res AS cdb_ymin,
FLOOR(ST_YMAX(cdb_full_bbox) / res) * res AS cdb_ymax
FROM
(
SELECT
${gridResolution(ctx)} AS res,
!bbox! cdb_full_bbox
OFFSET 0
) _cdb_input_resources
`;
};
// Function to generate the resulting point for a cell from the aggregated
const aggregatedPoint = (ctx, aggregated) => {
const placement = ctx.placement || DEFAULT_PLACEMENT;
@ -387,19 +407,7 @@ SELECT * FROM
((cdb_ymax - cdb_ymin) / res)::int as cdb_limit_y
FROM
(
SELECT
res,
CEIL (ST_XMIN(cdb_full_bbox) / res) * res AS cdb_xmin,
FLOOR(ST_XMAX(cdb_full_bbox) / res) * res AS cdb_xmax,
CEIL (ST_YMIN(cdb_full_bbox) / res) * res AS cdb_ymin,
FLOOR(ST_YMAX(cdb_full_bbox) / res) * res AS cdb_ymax
FROM
(
SELECT
${gridResolution(ctx)} AS res,
!bbox! cdb_full_bbox
OFFSET 0
) _cdb_input_resources
${gridInfoQuery(ctx)}
) _cdb_grid_bbox_margins OFFSET 0
) __cdb_src_params
WHERE the_geom_webmercator && cdb_point_bbox OFFSET 0