REST API Map Image Export and Scale Dependency

Question

I have been able to documented unexpected (for me) behavior regarding scale dependency and the map export method of the REST API. I have 3 map services on an ArcGIS Server (I am not the administrator so I cannot access it). Tiled Imagery Tiled Thematic Dynamic Thematic Scale dependency of all 3 layers is respected in a map control. When I produce a map image of the service using the REST export method, scale dependency is respected for the Tiled and Dynamic Thematic Services. But scale dependency is not fully respected for the Tiled Imagery service. The REST call to the service (omitting http:): /ArcGIS/rest/services/Imagery3/MapServer/ produces: Imagery3 (MapServer) View In: ArcMap ArcGIS Explorer ArcGIS JavaScript Google Earth View Footprint In: Google Earth Service Description: Map Name: Layers2 Layers: . . . Description: Copyright Text: Spatial Reference: 2264 Single Fused Map Cache: true Tile Info: Height: 512 Width: 512 DPI: 96 Levels of Detail: (# Levels: 4) Level ID: 0 [Start Tile, End Tile] Resolution: 28.25 Scale: 32544 Level ID: 1 [Start Tile, End Tile] Resolution: 13.0208333333333 Scale: 15000 Level ID: 2 [Start Tile, End Tile] Resolution: 6.51041666666667 Scale: 7500 Level ID: 3 [Start Tile, End Tile] Resolution: 1.73611111111111 Scale: 2000 Format: JPEG Compression Quality: 75 Origin: X: -121841900 Y: 154024800 Spatial Reference: 2264 Intial Extent: XMin: 1837306.32463124 YMin: 370328.619961146 XMax: 1861403.57463124 YMax: 393465.369961146 Spatial Reference: 2264 Full Extent: XMin: 267000.005956989 YMin: -20998.7395168134 XMax: 3192999.8740899 YMax: 1100997.84466795 Spatial Reference: 2264 Units: esriFeet Supported Image Format Types: PNG24,PNG,JPG,DIB,TIFF,EMF,PS,PDF,GIF,SVG,SVGZ,AI I don't expect to see image data with a scale value greater than 32544. Again in a map control, I do not. === When I call the REST map export method: /ArcGIS/rest/services/Imagery3/MapServer/export?f=pjson&bbox=1648619.791666668,490746.52777777775,1811380.208333335,599253.4722222222&size=700,400&transparent=true&format=jpg&layers=show:0,1,2,3,4,5,6,7&layerDefs= I get the following PJSON { "href" : "http:///arcgisoutput/_ags_map4a786ff41f0a487eb3713316aa17e2ea.jpg", "width" : 700, "height" : 400, "extent" : { "xmin" : 1635056.42361111, "ymin" : 490746.527777778, "xmax" : 1824943.57638889, "ymax" : 599253.472222222, "spatialReference" : { "wkid" : 2264 } }, "scale" : 312500 } Note the scale. When I change f=pjson to f=image, I get an image of the tiled data. As I zoom in, I continue to get an image result. But if I zoom out, say to where scale is "1250000", I no longer get the image. So it is partially respecting scale dependency. I cannot tell if this is a bug in the REST API, or a server setting I can't see on the returned PJSON. Any suggestions would be greatly appreciated. TJ

AxelSchaefer · Answer

If you're using the JS API as a client, you can test and verify the requests by adding the cached service as an esri.layers.ArcGISDynamicMapServiceLayer. The request will be an exportImage request.

If you add it to the client as a ArcGISTiledMapServiceLayer, it will request the tiles. If you have one tiled layer in your js api client, you will have the zoom steps according to the cache scales and you can only zoom in theses steps.

So it would be appropriate to access the tiled service as a dynamic one with an interpolated image.

HTH.

TJBara · Answer

As far as i know "export" operation is not using tiled data. It generates new image according to bbox, size e.t.c. Tiled data may be accessed via url: /ArcGIS/rest/services/Imagery3/MapServer/tile/// In this case scale level is predefined and cannot be different than during tiles configuration Maybe this will be helpfull: http://resources.esri.com/help/9.3/arcgisserver/apis/rest/index.html?export.html http://resources.esri.com/help/9.3/arcgisserver/apis/rest/index.html?tile.html Regards, Vasyl Thank you for your input, Vasyl. I am not sure it gets to the issue - I am getting expected behavior for other tiled services, and I am getting expected behavior from the imagery tiled service at different scales. Because I am trying to produce a printable image of the map service as represented in a map control, trying to pull a specific tile doesn't seem like the right approach. I appreciate you taking the time to respond. TJ

VasylMelnychuk · Answer

As far as i know "export" operation is not using tiled data. It generates new image according to bbox, size e.t.c. Tiled data may be accessed via url: /ArcGIS/rest/services/Imagery3/MapServer/tile/// In this case scale level is predefined and cannot be different than during tiles configuration Maybe this will be helpfull: http://resources.esri.com/help/9.3/arcgisserver/apis/rest/index.html?export.html http://resources.esri.com/help/9.3/arcgisserver/apis/rest/index.html?tile.html Regards, Vasyl