How to draw the color distribution map of annual precipitation in China with ArcGIS?

What I do is a mobile network base station, which is a bit similar to yours. In fact, it is to color the geometry with different colors in the layer.

/* Check the layers in the base station by drawing arbitrary polygons by users. There are some layers and surface layers, and you only need to pay attention to the surface layer */

if(geometry.type == "polygon"){

? Var graphicPolygon = new esri. Graphics (geometry, fill symbol);

? base map . graphics . add(graphic polygon)；

? var bSUrl = baseStationUrl

? bs URL = bs URL . replace(“{ G }”，“2G”)；

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ?

? var query 1 = new ESRI . tasks . query()；

? var query task 1 = new ESRI . tasks . query task(bSUrl+"/0 ")；

?

? query 1 . geometry = geometry；

? query 1 . spatial relationship = ESRI . tasks . query . spatial _ REL _ CONTAINS；

? //query . text = search text；

? //Filter the fields contained in the result set properties.

? query 1.outFields =)， 1)；

var fill symbol = new ESRI . symbol . simple fill symbol(

? ESRI . symbol . simplefillmasymbol . style _ SOLID，

? Line symbol,

? New esri. Color ([205,0,205,0.5])

? );

var length 2 = evt 2 . features . length；

for(var I = 0； I < length 2; I++){// Cyclic coloring

? var geometry2 = evt2.features[i]。 Geometry;

? Var graphicPolygon2 = new esri. Geometry2 (fill symbol);

? base map . graphics . add(graphic polygon 2)；

}

}