[postgis-tickets] r16877 - St_AsMVTGeom: Handle type changes in geometry collections
Raúl Marín Rodríguez
rmrodriguez at carto.com
Thu Oct 4 01:12:02 PDT 2018
Yep, you are right. The functionality is almost the same (except that
`lwgeom_get_basic_type` fails for invalid MVT types.
I've created a ticket (#4195) to review these functions and unify them,
and also change the return type from a simple `uint8` to an enum which
should make the code more readable.
On Wed, Oct 3, 2018 at 6:08 PM Darafei "Komяpa" Praliaskouski
<me at komzpa.net> wrote:
>
>
>
> On ср, 3 кас 2018, 07:11 Raul <raul at rmr.ninja> wrote:
>>
>> Author: algunenano
>> Date: 2018-10-03 04:11:12 -0700 (Wed, 03 Oct 2018)
>> New Revision: 16877
>>
>> Modified:
>> branches/2.5/postgis/mvt.c
>> branches/2.5/regress/mvt.sql
>> branches/2.5/regress/mvt_expected
>> Log:
>> St_AsMVTGeom: Handle type changes in geometry collections
>>
>> References #4181
>>
>>
>> Modified: branches/2.5/postgis/mvt.c
>> ===================================================================
>> --- branches/2.5/postgis/mvt.c 2018-10-03 10:52:58 UTC (rev 16876)
>> +++ branches/2.5/postgis/mvt.c 2018-10-03 11:11:12 UTC (rev 16877)
>> @@ -727,6 +727,39 @@
>> POSTGIS_DEBUGF(3, "parse_values n_tags %zd", ctx->feature->n_tags);
>> }
>>
>> +/* For a given geometry, look for the highest dimensional basic type, that is,
>> + * point, line or polygon */
>> +static uint8
>> +lwgeom_get_basic_type(LWGEOM *geom)
>
>
> It looks like lwgeom_dimensionality which is also a copy of lwgeom_dimension?
>
>
>
>
>> +{
>> + switch(geom->type)
>> + {
>> + case POINTTYPE:
>> + case LINETYPE:
>> + case POLYGONTYPE:
>> + return geom->type;
>> + case MULTIPOINTTYPE:
>> + case MULTILINETYPE:
>> + case MULTIPOLYGONTYPE:
>> + return geom->type - 3; /* Based on LWTYPE positions */
>> + case COLLECTIONTYPE:
>> + {
>> + uint32_t i;
>> + uint8 type = 0;
>> + LWCOLLECTION *g = (LWCOLLECTION*)geom;
>> + for (i = 0; i < g->ngeoms; i++)
>> + {
>> + LWGEOM *sg = g->geoms[i];
>> + type = Max(type, lwgeom_get_basic_type(sg));
>> + }
>> + return type;
>> + }
>> + default:
>> + elog(ERROR, "%s: Invalid type (%d)", __func__, geom->type);
>> + }
>> +}
>> +
>> +
>> /**
>> * In place process a collection to find a concrete geometry
>> * object and expose that as the actual object. Will some
>> @@ -734,27 +767,12 @@
>> * draw it anyways.
>> */
>> static void
>> -lwgeom_to_basic_type(LWGEOM *geom)
>> +lwgeom_to_basic_type(LWGEOM *geom, uint8 original_type)
>> {
>> if (lwgeom_get_type(geom) == COLLECTIONTYPE)
>> {
>> - /* MVT doesn't handle generic collections, so we */
>> - /* need to strip them down to a typed collection */
>> - /* by finding the largest basic type available and */
>> - /* using that as the basis of a typed collection. */
>> LWCOLLECTION *g = (LWCOLLECTION*)geom;
>> - LWCOLLECTION *gc;
>> - uint32_t i, maxtype = 0;
>> - for (i = 0; i < g->ngeoms; i++)
>> - {
>> - LWGEOM *sg = g->geoms[i];
>> - if (sg->type > maxtype && sg->type < COLLECTIONTYPE)
>> - maxtype = sg->type;
>> - }
>> - if (maxtype > 3) maxtype -= 3;
>> - /* Force the working geometry to be a simpler version */
>> - /* of itself */
>> - gc = lwcollection_extract(g, maxtype);
>> + LWCOLLECTION *gc = lwcollection_extract(g, original_type);
>> *g = *gc;
>> }
>> }
>> @@ -776,6 +794,7 @@
>> double height = gbox->ymax - gbox->ymin;
>> double resx, resy, res, fx, fy;
>> int preserve_collapsed = LW_TRUE;
>> + const uint8_t basic_type = lwgeom_get_basic_type(lwgeom);
>> POSTGIS_DEBUG(2, "mvt_geom called");
>>
>> /* Short circuit out on EMPTY */
>> @@ -832,9 +851,7 @@
>> /* For some polygons, the simplify step might have left them
>> * as invalid, which can cause clipping to return the complementary
>> * geometry of what it should */
>> - if ((lwgeom->type == POLYGONTYPE ||
>> - lwgeom->type == MULTIPOLYGONTYPE ||
>> - lwgeom->type == COLLECTIONTYPE) &&
>> + if ((basic_type == POLYGONTYPE) &&
>> !gbox_contains_2d(&pre_clip_box, lwgeom_get_bbox(clipped_geom)))
>> {
>> /* TODO: Adapt this when and if Exception Policies are introduced.
>> @@ -870,22 +887,11 @@
>> return NULL;
>>
>>
>> - if (lwgeom->type == POLYGONTYPE ||
>> - lwgeom->type == MULTIPOLYGONTYPE ||
>> - lwgeom->type == COLLECTIONTYPE)
>> + if (basic_type == POLYGONTYPE)
>> {
>> /* Force validation as per MVT spec */
>> lwgeom = lwgeom_make_valid(lwgeom);
>>
>> - /* Drop type changes tp play nice with MVT renderers */
>> - if (!(lwgeom->type == POLYGONTYPE ||
>> - lwgeom->type == MULTIPOLYGONTYPE ||
>> - lwgeom->type == COLLECTIONTYPE))
>> - {
>> - lwgeom_free(lwgeom);
>> - return NULL;
>> - }
>> -
>> /* In image coordinates CW actually comes out a CCW, so we reverse */
>> lwgeom_force_clockwise(lwgeom);
>> lwgeom_reverse_in_place(lwgeom);
>> @@ -893,8 +899,15 @@
>>
>> /* if geometry collection extract highest dimensional geometry type */
>> if (lwgeom->type == COLLECTIONTYPE)
>> - lwgeom_to_basic_type(lwgeom);
>> + lwgeom_to_basic_type(lwgeom, basic_type);
>>
>> + if (basic_type != lwgeom_get_basic_type(lwgeom))
>> + {
>> + /* Drop type changes to play nice with MVT renderers */
>> + POSTGIS_DEBUG(3, "mvt_geom: Dropping geometry after type change");
>> + return NULL;
>> + }
>> +
>> if (lwgeom == NULL || lwgeom_is_empty(lwgeom))
>> return NULL;
>>
>>
>> Modified: branches/2.5/regress/mvt.sql
>> ===================================================================
>> --- branches/2.5/regress/mvt.sql 2018-10-03 10:52:58 UTC (rev 16876)
>> +++ branches/2.5/regress/mvt.sql 2018-10-03 11:11:12 UTC (rev 16877)
>> @@ -273,6 +273,14 @@
>> 16,
>> true));
>>
>> +-- Geometry type change of one geometry of the multipolygon used to fallback to multilinestring
>> +SELECT 'PG46', St_AsEWKT(ST_AsMVTGeom(
>> + 'SRID=3857;MULTIPOLYGON(((-8230324.85567616 4984496.35685962,-8230307.1114228 4984654.46474466,-8230285.21085987 4984959.60349704,-8230324.85567616 4984496.35685962)),((-8230327.54013683 4984444.33052449,-8230327.23971431 4984450.39401942,-8230327.26833036 4984449.87731981,-8230327.54013683 4984444.33052449)))'::geometry,
>> + 'SRID=3857;POLYGON((-8238077.16046316 4989809.20645631,-8238077.16046316 4980025.2668358,-8228293.22084265 4980025.2668358,-8228293.22084265 4989809.20645631,-8238077.16046316 4989809.20645631))'::geometry,
>> + 4096,
>> + 16,
>> + true));
>> +
>> -- geometry encoding tests
>> SELECT 'TG1', encode(ST_AsMVT(q, 'test', 4096, 'geom'), 'base64') FROM (SELECT 1 AS c1,
>> ST_AsMVTGeom(ST_GeomFromText('POINT(25 17)'),
>> @@ -433,11 +441,11 @@
>> FROM (SELECT NULL::integer AS c1, NULL AS geom) AS q;
>>
>> -- Ticket #3922
>> -SELECT '#3922', length(bytea(ST_AsMVTGeom(
>> +SELECT '#3922', St_AsEWKT(ST_AsMVTGeom(
>> st_geomfromtwkb('\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
>> 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
>> 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'),
>> 'SRID=3347;POLYGON((3658201 658873,3658201 5958872.97428571,8958201.49428571 5958872.97428571,8958201.49428571 658873,3658201 658873))'::geometry,
>> 4096,
>> 0,
>> true
>> - )));
>> + ));
>>
>>
>> Modified: branches/2.5/regress/mvt_expected
>> ===================================================================
>> --- branches/2.5/regress/mvt_expected 2018-10-03 10:52:58 UTC (rev 16876)
>> +++ branches/2.5/regress/mvt_expected 2018-10-03 11:11:12 UTC (rev 16877)
>> @@ -48,6 +48,7 @@
>> PG43 - OFF|MULTIPOLYGON(((5 5,-1 -1,11 -1,5 5)),((5 5,11 11,-1 11,5 5)))
>> PG44|
>> PG45|
>> +PG46|SRID=3857;MULTIPOLYGON(((3245 2224,3262 2030,3253 2158,3245 2224)))
>> TG1|GiEKBHRlc3QSDBICAAAYASIECTLePxoCYzEiAigBKIAgeAI=
>> TG2|GiMKBHRlc3QSDhICAAAYASIGETLePwIBGgJjMSICKAEogCB4Ag==
>> TG3|GiYKBHRlc3QSERICAAAYAiIJCQCAQArQD88PGgJjMSICKAEogCB4Ag==
>> @@ -97,4 +98,4 @@
>> TU2
>> ERROR: pgis_asmvt_transfn: parameter row cannot be other than a rowtype
>> TU3|
>> -#3922|91
>> +#3922|MULTIPOLYGON(((2613 3664,2615 3662,2616 3662,2617 3665,2615 3665,2615 3664,2613 3664)))
>>
>> _______________________________________________
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>> postgis-tickets at lists.osgeo.org
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>
> --
> Darafei Praliaskouski
> Support me: http://patreon.com/komzpa
> _______________________________________________
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--
Raúl Marín Rodríguez
carto.com
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