Using Elevation Services in ArcMap
Topics in this section:
- 1 Adding and using the elevation services in ArcMap
- 2 Application of Elevation services in GIS analysis
- 3 Extracting height information at a point
- 4 Convert 2D features into 3D features
- 5 Raster image draped on elevation service
- 6 Generating Contours Dynamically Using Elevation Service
- 7 Integrating Hillshade into 2D Maps to Add Readability
- 8 Aspect and Slope
- 9 Extract an elevation profile of a line
- 10 Cut and Fill
- 11 Visibility analysis
- 12 Viewshed Analysis
- 13 Rendering Rules
- 14 Exporting Elevation Service Data for offline use
- 15 Canopy Height Model service symbology
Adding and using the elevation services in ArcMap
Please add the Public or Restricted elevation web services in ArcMap as described above in sections:
To apply function templates such as Aspect, Hillshade, Slope in Degrees or Slope Percent_rise to the elevation services, when the service is in a dynamic state with the tile_cache turned off, right-click on the elevation layer and open the Properties -> Processing Templates tab. Choose a function from the Function dropdown menu then Apply and OK:
To apply renderers to tile_cached elevation services please follow the instructions in Rendering Rules.
Application of Elevation services in GIS analysis
Elevation services provide a baseline for the GIS analyses and visualisations that support many common GIS elevation tasks. In many maps and GIS applications Elevation Services are used as a base height source. Some basic uses of Elevation Services are explained below with examples.
Extracting height information at a point
To obtain height information at a point, use the Identify tool when the DEM service is using the Default (None) renderer (not the Aspect, Hillshade, Slope or other renderers).
This tool returns an elevation value at that point. If more than one height source is available, then the returned value will be from the best resolution DEM project available and will display at the top of the elevation service window. In the following example where two elevation projects are available the Pixel Value (= Height), in this case the Anakie_2013_Twn project, is on top: it has the highest resolution of the two projects:
Convert 2D features into 3D features
It is often useful to have features with 3D geometry. Although you can display 2D features by draping them over a surface, 3D features are displayed more rapidly, and they can be shared with others without having to send along the surface data. There are also many 3D analytic operations that can take advantage of 3D geometry, including complementary technologies such as the ArcGIS Network Analyst extension. Using elevation services 2D features can easily be converted into 3D features. There are two geo-processing tools in ArcMap that allow you to obtain 3D properties from a surface: Interpolate Shape and Add Surface Information. Both tools require an ArcGIS 3D Analyst extension license and can be found in the Functional Surface toolset in the 3D Analyst:
Raster image draped on elevation service
This functionality is only available in ArcGIS Pro. Please see the workflow below in the ArcGIS Pro section of this document.
In the ArcScene stand-alone client, image and elevation services are not supported
Generating Contours Dynamically Using Elevation Service
This functionality is only available in ArcGIS Pro. Please see the workflow below in the ArcGIS Pro section of this document.
Integrating Hillshade into 2D Maps to Add Readability
If you place a Hillshade layer underneath the existing 2D layers in your map it gives viewers an impression of 3D. See the Topographic map below which is sourced from the Department of Resources QTopo Application. The Hillshade layer has been placed beneath the other layers giving a visual sense of the map contours:
In the elevation services, when the service is in a dynamic state with the tile_cache turned off, embedded raster functions as Processing Templates are available enabling visualisation of the DEM Hillshade. Users can use Hillshade in maps or models to make them look more realistic. Right click on the elevation service in the Table of Contents in ArcMap to open its Layer Properties and under the Processing Templates tab choose the Hillshade function and OK:
Aspect and Slope
As per the previous section, in the elevation services the Aspect and Slope functions can also be applied in the same way as the Hillshade function via the Processing Templates dropdown menu in the Layer Properties window, when the service is in a dynamic state with the tile_cache turned off. Or for further instructions see Rendering Rules.
Extract an elevation profile of a line
Profile graphs allow you to visualise elevation change over a continuous distance using 3D line geometry. In ArcMap you can make a profile graph for any line layer in the Table of Contents pane whether it is a line graphic converted using Graphics To Features via the Draw menu or a polyline feature class that has been converted to 3D using the Interpolate Shape tool in conjunction with the elevation service.
Use the output polyline in the 3D analyst extension Stack Profile tool
Making use of the output table of the Stack Profile tool allows an elevation profile to be viewed using View -> Graphs -> Create Graphs. The result can be customised by double clicking on the graph in the Elevation Profile window:
Cut and Fill
The Cut Fill tool is available in ArcMap to calculate cut and fill analysis of a ground surface involved in engineering projects. This tool requires two raster surfaces. The input before raster surface is an actual ground surface before construction, which is represented by an elevation service. The input after raster surface is a surface after construction which is an assumed surface or a surface to be constructed. In the example below a final surface with constant height of 170m is to be constructed with an outline as defined by the feature:
When we run the tool it gives a final output with Net Gain, Net Loss and Unchanged areas, plus the calculated Volume values are available in its attribute table:
Visibility analysis
What is visible from a location is an important element in determining for example the value of real estate, the location of telecommunications towers, or the placement of military forces. The shape of the terrain surface affects which parts of the surface someone standing at a given point can see. By using an elevation service layer you can check visibility from a point to its surroundings. The 3D Analyst extension Line of sight tool in ArcMap can be used to check visibility from a point:
Viewshed Analysis
A Viewshed is the area visible from a specific location. This analysis uses the elevation value of each cell from a DEM to determine the visibility from a particular cell or observation. Viewshed analyses are used to determine visibility to and from particular observation locations. Some examples may include determining visibility from roads, trails and fire observation stations. In ArcMap you need to have the Spatial and or 3D Analyst extensions licensed and enabled to access the Viewshed tools.
An example output image of a Viewshed analysis:
The use of a Digital Elevation Model (DEM) elevation in hydrology is very well established. Many hydrological analyses require an accurate DEM as an input; examples include watershed delineation, flood modelling, stream network extraction, river catchment delineation and flow modelling. Authorities responsible for performing hydrological analysis can use elevation services to perform GIS analysis on demand using the Hydrology toolset available in the Spatial Analyst toolbox in ArcMap.
Rendering Rules
In addition to applying Processing Templates functions in the Properties of the elevation services in their dynamic state, Rendering Rules can be applied via the Image Analysis window to all services in ArcMap. The difference is that Rendering Rules create an extra rendered layer in the Table of Contents. There are multiple ways of adding rendered layers to your map and one of the is described:
In ArcMap add an elevation service as described in Using Imagery Services in ArcMap
Open the Image Analysis Window from the Windows menu.
Click on the DEM service’s checkbox, and then select the “Image Analysis Options” button.
Click the Hillshade tab.
Make the following adjustments - Azimuth = 315; Altitude = 45; Z Factor = 2.5. Click OK.
Change the colour ramp to the grayscale colour ramp
If you do not change the colour ramp, the image generated will use the Shaded Relief function and NOT the Hillshade function.
Click the Shaded Relief button.
This adds a temporary raster dataset layer to the table of contents. You should now see the Hillshade as is shown in Queensland Globe.
Further adjustments can be made, in the Image Analysis window:
Right-click the new Hillshade in the table of contents and click “Properties” (or double click the layer).
Click the “Functions” tab.
Right-click Hillshade Function and click Properties.
Click the Hillshade tab and edit the properties, i.e. Multidirectional.
Click OK to close the Raster Properties Function dialog box and click OK again to close the Layer Properties dialog box.
Another way to add a rendered layer via the Add Function icon in the Image Analysis window to then Insert Function
Exporting Elevation Service Data for offline use
There is no option to clip from an elevation service in ArcMap, but you can export a tiff file from a Dynamic elevation service for offline use in the field and still obtain the height value of the topmost project in the service.
In ArcMap add a tile_cached (make sure to turn the tile_cache off), or dynamic elevation service to the TOC and make sure to apply the DRA in the Image Analysis window.
Zoom in to the area of interest.
Right click on the service layer in the TOC -> Data -> Export Data, which opens the Export Image Service Data window and apply the following settings:
Extent: Data Frame (Current)
Spatial Reference: Data Frame (Current)
Format: Tiff or Img
Check Cell Size
Check Uncompressed Size – if the output size is too big you may need to zoom in further.
It will also throw a warning when the size is too big.Save
In the TOC select the exported tiff layer and apply DRA on it
Using the Identify tool inspect its height. It will be the height value of the topmost project in the service.
Canopy Height Model service symbology
You’ll notice when you add the CHM service into ArcMap the symbology does not give a lot of difference in canopy height differences, and the height range of the layer is from 1 - 69.683 which is not quite right.
Change the Symbology by right-clicking on the layer in the Table of Contents, then choose the Symbology tab, choose a Stretch colour range, and OK. Open the Image Analysis window via the Windows menu, select and highlight the “Elevation\CanopyHeightModel” layer and tick the DRA box, you’ll see the display changes and the height range as well to 0.236 - 31.107 which are more realistic height values.
In the Symbology you can also choose Classified, but which puts the height values back to 1 - 69.683, but the DRA tick box is greyed out.