Connecting a WMS server to AutoCAD Map (the Greek Cadastre example)

For those of you not familiar with the subject, the entirety of Greece has been photographed by airplane during the years 2007 and 2008 on behalf of the Greek Cadastre (Εθνικό Κτηματολόγιο in greek). The resulting orthophotomaps are divided into Very Large Scale Orthomaps with pixel size in the scale of 20 cm (primarily covering urban areas) and Large Scale Orthomaps  with pixel size in the scale of 50 cm (which cover the rural areas and are the majority of the produced maps).

I have extensively worked on the quality checking of these images using GPS receivers during my time at the company SIMA S.A. and I can say that the resulting achieved horizontal accuracy is pretty high and can be used to complement the process of topographic mapping or urban/rural design on most cases.

The orthophotomaps are stored on a WMS server and can be inserted into AutoCAD Map as an overlay. To achieve this, you will need:

• AutoCAD Map 3d or Autodesk Civil 3d,
• a working internet connection as the map will be loaded in real time and
• the address of the Greek Cadastre WMS sever (http://gis.ktimanet.gr/wms/wmsopen/wmsserver.aspx).

First of all, you must open your drawing and define the coordinate system by entering the ADESETCRDSYS command in the AutoCAD command line.The "Assign Global Coordinate System" window will appear and you should press the "Select Coordinate System" button. Then proceed to select the 1987 Greek Grid.

Selecting a coordinate system

Confirm your choice and return to the AutoCAD command line. Issue the MAPCONNECT command which activates the Data Connect module. This function as it allows you to connect databases and spatial databases to your drawing, especially useful if you are working on a large or complex project.

On the Data Connect screen, choose "Add WMS Connection" on the left and then proceed to fill in the blanks on the right. The "Connection name" field is not important but you should enter the WMS address given above in the "Server name or URL" field and choose 1.3.0. from the dropdown menu "Version". Press "Connect" when you are done.

The Data Connect window

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Next, you will be prompted for a username and password. These are not important as the data is available to the public for free (for more information on this, please visit geodata.gov.gr, page in greek) so you should press "Login" to proceed.

On the next screen, make sure you click on the check-box next to "THE BASEMAP OF KTIMATOLOGIO" and that you validate the Map Coordinate System to avoid disastrous results. When you are done, click on "Add to Map" twice to connect the data. You should refrain from clicking again on "Add to Map" as it will make a new connection and load the data again, resulting in your RAM memory overloading with data. 

Notice the "Disconnect" button on the lower part of the dialogue box. You should keep it in mind In case you need to remove the connection from your drawing.

Finalizing the connection

Exit the Data Connect dialogue box and issue a ZOOM EXTENTS command in order to switch to an overview of the mosaic as it is transformed in the Universal Transverse Mercator projection. Zoom in to achieve better resolution and get to your area of interest. 

An orthophotomap of the city of Athens inserted in the workspace of AutoCAD Civil 3d 2011

  

You are done here.