Connect and import imagery from a Web Mapping Service: FEMA National Flood Hazard Layer Example

A very unique feature of Plex.Earth 3.3, is the ability to connect to any Web Mapping Service may be useful for you to work on, and accordingly import imagery to your AutoCAD project.

 

A vast database of such WMS's is readily available for free, especially from government sources (United KingdomUnited States of America etc.) or agencies (e.g. FEMA) relating to useful information for companies and professionals (e.g. flood hazard maps, topographic maps)

 

In this tutorial, we are going to utilize this feature to connect to FEMA's National Flood Hazard Layer WMS and import imagery into our AutoCAD project, where further editing can take place. Here is how:

 

Step 1: Add a background Map Template from the Map Explorer window

Adding a template, will serve as a background map to the WMS we will import later on. You can choose any of the readily available templates (e.g. Bing Maps Aerial).

Add_Bing.jpg

 

Step 2: Select Add Content -> Web Map Service (WMS) from the Map Explorer window 

Click on the "Add content" function of the Map Explorer Window and select "Web Maps Service (WMS)"

Add_Content_WMS.jpg

 

Step 3: Copy the URL of your selected WMS 

Plex.Earth 3.3 will now prompt you to add a WMS server. All you need to do is copy the URL address of your preferred WMS and paste it to the text box provided. In this example, we are going to use FEMA's National Flood Hazard Layer WMS URL, which can be found in the following link, by scrolling down:

https://hazards.fema.gov/femaportal/wps/portal/NFHLWMS/

 

FEMA_URL.jpg

 

If you wish to try out this WMS, simply copy and paste the following URL, which is specific for FEMA's NFHL WMS Server:

https://hazards.fema.gov/gis/nfhl/services/public/NFHLWMS/MapServer/WMSServer

2017 Update: Due to a recent change in security settings, https links might not work. In that case you can use this link: http://hazards.fema.gov/gis/nfhl/services/public/NFHLWMS/MapServer/WMSServer

 

Step 4: Select the layers you wish to view 

 WMS's may contain numerous layers for you to view. It's up to the user to select the desired content of the resulting map.

In this example, we will select the "Flood Hazard Zones", "Flood Hazard Boundaries" and "NFHL Availability" layers

Layer_Selection.jpg

 

Step 5: Edit layers to make them transparent 

WMS layers are usually non-transparent, thus obscuring the view of the background Map Template. In order to make the layers transparent and achieve the desired result, you have to do the following, through the options that are available in our WMS Layer Properties Window:

1. Image Format: Make sure that a /png format is selected. If not, then change the Image Format to /png manually. This is essential, as /png formats alone offer the transparency attributes.

2. Layer Color: Make sure that the color selected is set to Transparent. If not, then use the Use Τransparent option on the right.

Make_Transparent.jpg

 

Step 6: Import imagery 

The resulting image in your Map Explorer window, after zooming, should look like this:

Resulting_image_with_both_WMS.jpg

 

If we zoom even closer to the Manhattan area, we can see the Flood Hazard Zones and Boundaries (see Note):

Zoom_Manhattan.jpg

 

Now you can utilize Plex.Earth's capabilities and import georeferenced images by following this tutorial.

 

Step 7: Manage layers 

In case you want to select different layer of the WMS to view, or even edit them, the process is pretty simple.

In the Map Explorer Window, simply right-click the WMS whose layers you wish to edit, and select the "Source Properties" option. This will open the WMS Source Properties window.

Manage_layers.jpg

 

Click the "Manage Layers" button and the familiar WMS Layer Properties window will open (see Steps 4 & 5).

 WMS_Source_Properties.jpg

 

From there, you can select or deselect the layers you wish, or even edit their attributes.

 

Conclusions: 

With thousands of Web Map Services available through Open Data sources, containing valuable information for companies and professionals, Plex.Earth 3.3 offers the capability to view them within AutoCAD, and even import them for further editing and usability.

 

 

Note 1: 

Don't be alarmed if the WMS layers you have selected are not showing straight away. Certain layers appear only when you have reached a specific zoom. This information is usually stored within the capabilities file of the WMS.

If you wish to access information about the layers you have selected, certain attributes are directly available through the WMS Layer Properties Window

Scale_Denominator.jpg

For example, in the FEMA NFHL WMS we just covered, the "Flood Hazard Zones" layer is only available when the zoom (Max Scale Denominator) is set to 1:47247.023810 or lower. 

If we had selected only this layer, we wouldn't have been able to view it, unless we zoomed to an acceptable scale value.

 

Note 2: 

It is generally advisable, especially if the WMS is not working properly (see Note 1), that you look into the capabilities file for information about the WMS and its parameters.

Should you wish to access the Capabilities file, you can simply select the corresponding tab, in the WMS Layer Properties window. 

WMS_Capabilities.jpg

 

Often, the capabilities file can also be found in the location from which you obtained the WMS Server URL.

 Capabilities_URL.jpg

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