New function of SuperMap iserver11i -- release and use of legend

author ：yyy

Preface

        A map legend is a symbol that represents geographical things on a map , It is the description of the contents and indicators represented by various symbols and colors on the map , Focus on one corner or side of the map . The legend shall conform to the principles of completeness and consistency . The legend has a dual task , When compiling a map, it serves as a criterion for diagramming the contents of the map , As an essential reading guide when using drawings . It helps users to use the map more conveniently 、 Understanding map content .

         Currently in SuperMap iServer11i In the new version, the map service has added legend Sub resources , It supports obtaining the legend information of all map layers at one time , You can also return the specified range 、 Specify the legend information of the layer , Next, we will try it out SuperMap 11i Beta Version of the series products to realize the application of the legend .

One 、 Make and publish legend

adopt SuperMap iDesktop When making the map of the product, we were “ Layer manager ” Create a new layer group in , Layer control , Change the layer style 、 Create thematic maps, etc. to build a default or custom legend map ; Then save the map 、 Save the workspace . The picture below is through SuperMap iDesktop 11i Beta Two maps produced by version , One of them is through custom layer groups 、 legend 、 A map made by means of thematic maps ; The other is that only the layer group is set , The legend uses a map made by default , The display effect of the two maps is as follows ：

         When the map is made, we can go through SuperMap iServer 11i Beta Version publishes the above workspace as a map service , Then in the map service “ The following operations are supported ” There will be one in the list “legend” Figure example resources , When you click to access “legend” Then we can see in “ Layer legend list ” The legend objects of all layers in the current map are displayed one by one , Here you can find that the effect in the currently displayed legend object follows iDesktop in “ Layer manager ” The effect is consistent in , Both contain layer group content .

Two 、 Application of legend

         When we get the legend information, how can we get its specific style and use it ？ Here's how to get the legend details and style content by request . Through the above service address , We can see that the request header format of the legend object has a default fixed content , Such as ：" Map service address "+"legend"+"?"+"​bbox=xmin,ymin,xmax,ymax"; The representation format of the legend object by changing is rjson after , We can more clearly see the description of a legend object by default ：

{"layerLegends": [{
    "subLayerLegends": [
        {
            "subLayerLegends": [{
                "subLayerLegends": null,
                "layerType": "UGC",
                "legends": [{
                    "imageData": "iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAAJUlEQVQ4jWNMS0v7z0ABYAERVZk1ZBvARIntowaMGjBqABUNAABexQOygF8COgAAAABJRU5ErkJggg==",
                    "values": null,
                    "width": 16,
                    "label": "[email protected]",
                    "contentType": "image/png",
                    "url": "http://localhost:8091/iserver/output/resources/testcountries/SYMBOLFILL/0_-58026551.png",
                    "height": 16
                }],
                "maxScale": 0,
                "layerName": "[email protected]",
                "minScale": 0
            }],
            "layerType": "UGC",
            "legends": [{
                "imageData": "iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAAVElEQVR42mNgGBRA3rP2CBD/x4LPKLtVyxJjwH88+D4QG1JiABquO0yhAbVHcBog51lrTW4ggg0gEKC4vYJmANHeGWYGHIFFD1kGwAAoGilKDwMCAG1C9/N/2myFAAAAAElFTkSuQmCC",
                "values": null,
                "width": 16,
                "label": "LayerGroup#1",
                "contentType": "image/png",
                "url": "http://localhost:8091/iserver/manager/static/Theme/image/layerGroup.png",
                "height": 16
            }],
            "maxScale": 0,
            "layerName": "LayerGroup#1",
            "minScale": 0
        },
        {
            "subLayerLegends": null,
            "layerType": "UGC",
            "legends": [{
                "imageData": "iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAAJUlEQVQ4jWNMS0v7z0ABYAERPT0hZBvARIntowaMGjBqABUNAACQNAO/KgaADgAAAABJRU5ErkJggg==",
                "values": null,
                "width": 16,
                "label": "[email protected]",
                "contentType": "image/png",
                "url": "http://localhost:8091/iserver/output/resources/testcountries/SYMBOLFILL/0_858832806.png",
                "height": 16
            }],
            "maxScale": 0,
            "layerName": "[email protected]",
            "minScale": 0
        }
    ],
    "layerType": "UGC",
    "legends": [{
        "imageData": "iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAAVElEQVR42mNgGBRA3rP2CBD/x4LPKLtVyxJjwH88+D4QG1JiABquO0yhAbVHcBog51lrTW4ggg0gEKC4vYJmANHeGWYGHIFFD1kGwAAoGilKDwMCAG1C9/N/2myFAAAAAElFTkSuQmCC",
        "values": null,
        "width": 16,
        "label": "LayerGroup",
        "contentType": "image/png",
        "url": "http://localhost:8091/iserver/manager/static/Theme/image/layerGroup.png",
        "height": 16
    }],
    "maxScale": 0,
    "layerName": "LayerGroup",
    "minScale": 0
}]}

          Through the request, we got the json Format content , Now, let's introduce in detail what each parameter means . among url The parameter is the legend image we need to use .

Response Schema: application/json
{
	layerLegends	//Array of object Legend information of each layer 
		Array [
			layerName	//string  Layer Name 
			layerType	//string  The layer type 
			minScale	//number  Layer minimum visible scale 
			maxScale	//number  Layer maximum visible scale 
			legends		//Array of object  Each legend item information of the layer 
				Array [
					label		//string  Legend label 
					imageData	//string  Legend picture content base64 Express .
					url			//string  Legend picture url
					contentType	//string  Type of legend picture , Only for now png
					width		//string  The width of the legend picture , Default 16 Pixels 
					height		//string  The height of the legend picture , Default 16 Pixels 
					values		//object If it is a segmented thematic map ,values={start:startValue,end:endValue}, The default segment range is [start,end); If it is a single value thematic map ,values={unique:uniqueValue}
				]
			subLayerLegends LayerLegend[]	// Legend of each sublayer .subLayerLegends  The type is  LayerLegend[].
		]
}

         So in other cases , How to customize the request header method to obtain the legend information that meets the conditions ？ According to the help documentation , adopt “mapLegend” Resources represent the collection of legend information of each layer of the map to obtain the legend information of each layer of the map . 

path Parameters（ Path parameter ）	mapname （ Required ）(string)	Map name
query Parameters（ Request parameters ）	bbox (string)	Query the legend of the layer that intersects with this rectangle , When layers When the parameter is not set ,bbox Is a required parameter . Format ：bbox=xmin,ymin,xmax,ymax
	layers (string)	Layer filtering , When bbox When the parameter is not set ,layers Is a required parameter . grammar ：layers=[show|hide]:[layerName]@@[layerGroupName]@@[mapName].show Indicates that only the legend of the specified layer is returned ,hide Indicates that the specified layer legend does not return , Other queried layer legends are returned . Support multiple layers , The layers are separated by commas . Such as show:[email protected]@@World, To return only World Map [email protected] Legend for layer .
	transparent (boolean)	Whether the background of the legend image is transparent . The default is true.
	returnVisibleOnly (boolean)	Whether to return only the legend of the visible features within the current map range . The default is false.
	mapScale (number)	Map scale . When returnVisibleOnly by true when ,mapScale Is a required parameter .
	width (integer)	Returns the width of the legend . Default 16 Pixels .
	height (integer)	Returns the height of the legend . Default 16 Pixels .

         Request parameters through the above request header , We can customize the request content , To return the legend information that meets the custom requirements , For example, here we return to the specified layer "world" and "LayerGroup#1 Medium Countries" Two legends for , Then the content of the request header should be like this ：

http://localhost:8091/iserver/services/map-testmap/rest/maps/testcountries/legend?layers=show:[email protected]@@[email protected]@testcountries,[email protected]@@[email protected]@[email protected]@testcountries

among “[email protected]@@[email protected]@testcountries” and “[email protected]@@[email protected]@[email protected]@testcountries” For the contents of the map sublayer set , We can pass in "layers" Object , By customizing “layers” object , We can get the legend information of the specified layer set , The results are as follows ：

​

3、 ... and 、 matters needing attention

What should be paid attention to during the use of the legend ：

        1、 stay 11i beta In the previous version , We can also use the layers Object to get the legend of a single layer , Such as ：http://localhost:8091/iserver/services/map-testmap/rest/maps/testworld/layers/[email protected]@@[email protected]@[email protected]@testworld/legend, among “[email protected]@@[email protected]@[email protected]@testworld” Name the layer , However, only one legend can be obtained at a time , And for the thematic map layer, the legend of a specific value or range cannot be obtained ;

        2、 For the legend , Only the legend object of the map service published in the workspace has content , Because the legend information is saved in the map , For the map service of tile Publishing , Its legend is empty ;

        3、 In the layer legend list , The display order and level of each legend are the same as that of the map iDesktop In the layer manager , If there is a problem with the display , Please update iServer To the latest version .