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Graphic Processing

Updated 2026-03-07~ 18 min read
.md
ChatGPTClaudeKimiDoubao

Graphic processing is generally implemented in two ways:

  • Method 1: Compose into a new map with composeNewMap
 /**
 * Compose into a new map
 * @param param Compose parameters
 * @return {Promise<any>}
 */
composeNewMap(param: IComposeNewMap | IComposeNewMap[]): Promise<any>;
/**
 * Compose new map parameters
 */
export  interface IComposeNewMap {
    /** Map ID. */
    mapid: string;
    /** Map version (uses current open map version when empty). */
    version?: string;
    /** Map clip bounds, format [x1,y1,x2,y2]; empty means no clipping */
    clipbounds?: [number, number, number, number];
    /** Select contain or intersect (default false for contain, true for intersect) */
    selByCrossing?: boolean;
    /** Four parameters (x offset, y offset, scale, rotation in radians), optional, for final coordinate correction */
    fourParameter?: [number, number, number, number];
    /** Whether to use inverse four-parameter calculation, default false */
    isInverseFourParamter?: boolean;
    /** Layer names to display; empty means all layers */
    layers?: string[];
    /** Layer name prefix for the new map; if set to null, no default prefix. Without prefix, layer name conflicts may cause different rendering when layer attributes are set */
    layerPrefix?: string;
    /** Layer name suffix for the new map */
    layerSuffix?: string;
    /** Output file name; empty means auto-generated from parameters */
    savefilename?: string;
    /** Purge graphic data after generation to reduce DWG file size */
    purge?: boolean;
    /** When entities come from other maps, auto-rename block definitions if duplicated, default true */
    isRenameBlockNameIfExist?: boolean;
    /** Whether to zoom to extent after creation, default false (for multi-map merge, only set for the first map) */
    isZoomExtents?: boolean;
    /** CAD version for export. Use * for current CAD map version */
    cadVersion?: string | "*" | "cad2000" | "cad2004" | "cad2007" | "cad2010" | "cad2013" | "cad2018";
}

Example: Extract data from several layers of a CAD map and save as a new map

let svc = new vjmap.Service(env.serviceUrl, env.accessToken)

// js code
let res = await svc.composeNewMap({
    mapid: "sys_zp",
    vesion: "v1",
    layers: ["red line", "road"]
})
  • Method 2: Create a new map based on a template map
export  class DbDocument {
    /** Source map for modification or add/delete; format mapid/version, e.g. exam/v1 */
    from?: string;
    /** When from is set: select specified layers from source map; entities not in specified layers will not display */
    pickLayers?: string[];
    /** When from is set: select specified entity IDs from source map; entities not in specified IDs will not display */
    pickEntitys?: string[];
    /** When from is set: use expression to select entity IDs; union with pickEntitys results */
    pickExpr?: string;
    isClearFromDb?: boolean;
    /** Document environment for settings like line width display; LWDISPLAY: true to show, false to hide line width */
    environment?: Record<string, any>;
    /** Entity set. */
    entitys?: IDbEntity[];
    /** Layer set. */
    layers?: IDbLayer[];
    /** Text styles. */
    textStyles?: IDbTextStyle[];
    /** Dimension styles. */
    dimStyles?: IDbDimStyle[];
    /** Linetypes. */
    linetypes?: IDbLinetype[];
    /** Block definitions. */
    blocks?: IDbBlock[];
    /** When entities come from other maps, auto-rename block definitions if duplicated, default true */
    isRenameBlockNameIfExist?: boolean;
    /** Whether to zoom to extent after creation, default false */
    isZoomExtents?: boolean;

    //... other methods omitted
}

Example: Extract data from several layers of a CAD map and save as a new map

let svc = new vjmap.Service(env.serviceUrl, env.accessToken)
let doc = new vjmap.DbDocument();
doc.from = "sys_zp/v1";
doc.pickLayers = ["red line", "road"]
// js code
let res = await svc.updateMap({
    mapid: vjmap.getTempMapId(),// Temporary map auto-delete time in minutes when not browsed. Default 30
    filedoc: JSON.stringify(doc),
    mapopenway: vjmap.MapOpenWay.Memory,
    style: {
        backcolor: 0 // If div background is light, set to oxFFFFFF
    }
})

Clipping Graphics

let svc = new vjmap.Service(env.serviceUrl, env.accessToken)

// js code
let res = await svc.composeNewMap({
    mapid: "sys_zp",
    vesion: "v1",
    /** Map clip bounds, format [x1,y1,x2,y2]; empty means no clipping */
    clipbounds?: [x1,y1,x2,y2];
})

Coordinate Transformation

let svc = new vjmap.Service(env.serviceUrl, env.accessToken)

// js code
let res = await svc.composeNewMap({
    mapid: "sys_zp",
    vesion: "v1",
    /** Four parameters (x offset, y offset, scale, rotation in radians), optional, for final coordinate correction */
    fourParameter?: [number, number, number, number];
})

Merging Graphics

// --Graphic processing to compose new graphics--Process graphic list, then compose into a new graphic
let svc = new vjmap.Service(env.serviceUrl, env.accessToken)
// Compose into new map: process sys_world, then merge with sys_hello to generate new map file
let rsp = await svc.composeNewMap([
    {
        mapid: "sys_world", // Map id
        // Parameters below can be set as needed for layer, bounds, coordinate transformation
        //layers: ["latlon labels","COUNTRY"], // Layer name list to display
        //clipbounds: [10201.981489534268, 9040.030491346213, 26501.267379,  4445.465999], // Bounds to display
        //fourParameter: [0,0,2,0] // Four-parameter transformation for the map
    },
    {
        mapid: "sys_hello"
    }
])
if (!rsp.status) {
    message.error(rsp.error)
}
// Return result:
/*
{
    fileid: "pefbe7459b06",
    mapdependencies: "sys_world||sys_hello",
    mapfrom: "sys_world&&v1&&&&0&&&&&&&&&&&&10||sys_hello&&v1&&&&0&&&&&&&&&&&&2",
    status: true
}
 */
Runs in a sandbox against the VJMAP public demo service


Graphic arrangement and composition example

Extracting Layers

You can also use the layers parameter of composeNewMap to extract layers. Here DbDocument is used as an example:

Runs in a sandbox against the VJMAP public demo service


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