VirtualSite: overlay Matterport scan on Google Maps (using point pairs)

The ability to overlay Matterport scans on Google Maps is a new feature for the VirtualSite platform. We provide users with two alternative methods to do this;

• Align using Drag and Drop: much easier and faster using a new drag and drop tool (see overlay Matterport scan on Google Maps using drag and drop for more info)
• Align using Point Pairs: more accurate but slower process (see below for more info).

Why point pairs?

The rationale behind mapping point pairs in this way is to provide Matterport users with a mechanism to "accurately" align scans without the guess work of manually overlaying a scan. This means ascertaining the correct latitude and longitude for a number of locations in your Matterport scan. The easiest way to do this would be to use a GPS while scanning your site to log latitude and longitude data of selected landmarks. If you do not have access to a GPS or GPS data, other alternatives include; using known coordinates from any construction documentation (e.g. floorplans); or even using Google Maps satellite view. For the purpose of this guide, we have chosen to  use Google Maps satellite view. 

Note: currently, mapping point pairs is the only way to align Matterport scans with Google Maps using the VirtualSite platform. Depending on user interest and feedback for this feature we may look at adding functionality to manually align scans in subsequent releases.

Example: overlaying an outdoor scan on Google Maps

For this example, we have chosen to use a scan of an outdoor area that includes a large pool. This will allow us to geolocate the same area using Google Maps and extract enough common points to accurately align the scan.

How to

Steps 1 - 3

1) Navigate to the "Home" page for your site located at https://cloud.veriscian.com/virtualsite/{your-site-id}/home. If you are logged in already, you can also navigate to the "Home" page via the drop down menu at the top right of the page.

2) The first step in the process is to choose a number of landmarks to use when mapping point pairs. When choosing landmarks it’s important to choose something that is prominent as it helps to minimise any chances of making a mistake. In this example, we are attempting to align a scan of an outdoor area, therefore we have chosen to use the four(4) corners of the pool as a landmark.

3) Hold down the "alt" key and the "p" key at the same time (alt + p) and move your cursor over the scan. This will cause a small box to appear in the bottom left corner of the viewer containing x-y coordinates. These values represent the local x-y coordinates of your Matterport scan. As you move the cursor, these values will update automatically. While holding the "alt" + "p" keys, move the cursor to your first landmark. Once the cursor is in position, release the "alt" + "p" keys to lock the x-y values. This will allow you to move the cursor again without the x-y values updating. Select the x-y values, copy the values to clipboard and then paste into a separate text file or spreadsheet for later use.

Steps 4 - 5

4) Open another browser window to Google Maps. Ensure you have google "earth" view selected and navigate to your scan location using the Google Maps search tool. 

5) Open the Google Maps menu options and ensure you have selected "3D off". Please note that this is an important step if you are using Google Maps to get latitude and longitude data. This will change the "earth" view to a flat 2D representation. If 3D mode is not turned off, you will likely get distorted latitude and longitude values.

Steps 6 - 7

6) Find the corresponding landmark in Google Maps (in our case, the corner of the pool) and right click to reveal a menu.

7) Within the options menu, select "What's here?"

Step 8

8) A marker will now appear over your selected landmark with a new window at the bottom of your screen showing latitude and longitude. Highlight the latitude and longitude values, copy to clipboard and then paste into your separate text file or spreadsheet (alongside matching x-y coordinate). Repeat the above steps a number of times until you have a list of point pairs. 

Step 9

9) Navigate to the "Models" page for your site (located at https://cloud.veriscian.com/virtualsite/{your-site-id}/models). Find your Matterport scan in the list and select the menu button (three dots icon). Then within the pop up menu, select the "Transform" option.

Steps 10 - 12

10) Within the "Transform" dialog, paste the point pairs you have collected from previous steps. The point pairs must be formatted such that each row corresponds to a new landmark with values in order of [X, Y, lat, lng] where X & Y refers to the Matterport scan coordinates from step 3 and lat & lng are the corresponding latitude and longitude from step 8. Values must be separate by comma, semicolon or tab with the mapping for each point on a new line. If you are having trouble with pasted values being properly parsed, the best option is to layout your mappings in a spreadsheet then copy the entire cell range to clipboard and paste into the dialog box. Please note that you must provide a minimum of three(3) point mappings to this feature. In this example, we used four(4) but there is no maximum to the number of mappings. We would recommend you provide as many point mappings as is practical. This will ensure an “averaged” transform is used to align your scan which will help to minimise the impact of errors from individual point pairs.

11) If the pasted values have been properly parsed, you will see a message below with an “example row”. This makes it easier to spot any mistakes in your input and will help you to sense check the pasted values.

12) If the input values look ok, select "Transform" to start processing.

Step 13

13) While your scan is being processed, you will see a loading icon in the "Transform" column. Processing typically takes around 15mins.

Step 14

14) Once complete, the loading icon will change to a "tick"

Steps 15 - 18

15) Navigate back to the "Home" page for your site (located at https://cloud.veriscian.com/virtualsite/{your-site-id}/home).

16) In the top left corner of the viewer, you should now see additional options to toggle between satellite, map and CAD mode. The satellite and map options will toggle the background between Google Maps satellite view and roadmaps view. The CAD option will revert back to the default view (i.e. without any Google Maps background). 

17) Select the globe icon in the info panel to toggle between Google Maps and CAD mode. Alternatively, you can select the desired mode from the drop down menu immediately below. 

18) If successful, the Matterport scan should now be overlayed on Google Maps. Please note that while satellite or map mode is selected, your zoom will be restricted to the maximum zoom allowed by Google Maps. If you wish to revert back to higher zoom levels, simply select "CAD" mode and this will hide the Google Maps background. If you find the scan has been poorly aligned, it is possible to repeat the process. A good approach is to first retrace your steps to see if a mistake has been made in any of the above steps. A few common pitfalls worth checking are; not turning of "3D mode" on Google Maps, errors made while copying and pasting values, not enough point pairs.