PostGIS助力地圖可視化

1、PostGIS助力地圖可視化GIS定義標準定義：空間數(shù)據(jù)采集（ 測繪、遙感、航測、G P S ）空間數(shù)據(jù)管理（ 空間數(shù)據(jù)庫）空間分析（ 空間統(tǒng)計、數(shù)據(jù)分析、算法）地圖可視化 （ w e b g i s , q g i s ）旁人定義：地圖可視化地圖底圖地圖引擎( m a p b o x , e c h a r t s , m a p v , L 7 )數(shù)據(jù)渲染速度數(shù)據(jù)渲染速度提供更合適的數(shù)據(jù) 給地圖渲染引擎是時候表演真正的技術(shù)了一些可視化樣例PostGIS助力地圖可視化PostGIS助力網(wǎng)格類可視化PostGIS助力距離類可視化PostGIS助力熱力圖與等高(時,勢)線類可視化PostGIS助

2、力Raster類可視化PostGIS助力其他可視化PostGIS助力網(wǎng)格類可視化網(wǎng)格可視化需求：1、各種類型網(wǎng)格的生成（六邊形、矩形、平行四邊形、圓形、扇形等）2、根據(jù)網(wǎng)格進行統(tǒng)計（求和、求平均、求中數(shù)、求總和）3、其他需求（空隙、旋轉(zhuǎn)、求交）PostGIS助力網(wǎng)格類可視化六邊形矩形、平行四邊形圓形旋轉(zhuǎn)ST_Scale ,ST_MakeEmptyRaster, hex_grid, ST_SetSRID , ST_PixelAsPolygons, ST_Rotate , st_centroid, st_geomfromtext、st_astextSELECT geom FROM (SELECT

3、(ST_PixelAsPolygons (ST_AddBand (ST_SetSRID ( ST_MakeEmptyRaster ( 50, 30, 119.96, 30.40, 0.01,- 0.01, 0.01, 0 ), 4326 ),8BSI :TEXT,1,0 ),1,FALSE ).geom ) T -矩形select ST_Rotate(geom,RANDOM()*3.14,st_centroid(geom) geom from (select st_geomfromtext(st_astext(ST_Scale(geom,POINT(0.80 0.80),st_centroid

4、 (geom),4326) geom from (SELECT hex_grid(5, 119.95, 30.03, 120.43, 30.43, 4326, 3857, 4326) geom) t) k; -旋轉(zhuǎn)select st_buffer(st_centroid(geom):geography,1000):geometry as geom from (select st_geomfromtext(st_astext(ST_Scale(geom,POINT(0.85 0.85),st_centroid (geom),4326) geom from (SELECT hex_grid(5,

5、119.95, 30.03, 120.43, 30.43, 4326, 3857, 4326) geom) t) k ; -圓形PostGIS助力網(wǎng)格類可視化扇形generate_series、ST_ExteriorRing、st_difference、st_buffer、lag、st_makeline、ST_AddPoint、ST_MakePolygon、st_reverse、st_intersection、st_startpoint、st_transform、ST_Centroid、st_x、st_y、st_geomfromtextPostGIS助力距離類可視化嘗試距離可視化需求：直線距離

6、網(wǎng)絡(luò)距離PostGIS助力距離可視化PostGIS助力熱力圖與等高(時、勢)線可視化St_npoints st_nrings st_numgeometries St_points St_generatepoints St_node St_segmentizePostGIS助力Raster類可視化PostGIS助力Raster類可視化Postgis:0.4s,1000點QSIS:5s,300點Arcgis:0.8s,1000點PostGIS助力raster類可視化PostGIS助力其他可視化PostGIS助力其他可視化st_expand, st_orientedenvelope結(jié)語PostGIS不只是個數(shù)據(jù)庫插件。PostGIS是一個深度