Before you start Capturing

This is a collection of instructions and best practices to accurately capture your city environment.

How to Capture

https://drive.google.com/file/d/1Wys5tLhTbb14qlV26Xi9HSNb85Xj8w22/viewdrive.google.com

Positioning yourself and capturing locations

Terminology and concepts

Term	Meaning
Location	Street chosen to be photographed
Point	One point, in which you should capture photos, rounding
Passage	The path during which you capture photos in points, located at a certain distance to the facades. Every distance is another passage - 5 meters, 10 meters and more.
Lateral step	Displacement between each point along each passage
Visual Overlap	Adjacent images must capture at least 50% of the same area. You should take the next frame in such a way that it captures half of the area available in the previous frame. To simplify the task, mentally divide the area in the frame in the middle with a vertical line and turn until this line is at the left or right border of the screen

General Process

The general process is very simple. With Augmented City you can:

1. Capture a Location with a smartphone,

2. Add data objects, and

3. View them

Positioning yourself

Before you start capturing frames, you should choose the area in which you will be working. You should open your preferred map application (Google Maps for example), find the street you are going to scan and, if necessary, divide it into sections no more than 100 meters. This way each section will be a separate location. See image below

Each area in green and blue constitutes a section

What are Section Areas

• If your chosen area of the street is located between 2 crossroads and no more than 100 meters it will be one single location.

• Every crossroad should be captured as a separate location.

• You can see an example of choosing locations on the picture below (green rectangles – street, blue rectangle - crossroad):

• After you chose location, you can start capture photos.

General Recommendations

• You should practice before start shooting! If you shoot Typical, Wide streets, Crossroads or Squares - you should acquire photos with the horizontal orientation of the device (LANDSCAPE) (about 15 photos in a point), making a complete rotation at a point in at least 15 seconds at a constant speed.

• If you acquire photos with a vertical orientation of the device (PORTRAIT) for “narrow streets” – you should capture about 25 photos at the one point, making a complete rotation at a point in at least 25 seconds.

• If the distance from the central line of the street to the facade is closer than 2 meters, you should use a half-star approach described in paragraph 2, which is used for shooting very narrow pedestrian streets.

• You should try to get as little ground\sky on the photo as possible.

• You should try to take a photo so that the bottom border of the frame matches the base of the facade.

• If at any point a foreign object (pillar, road sign, public transport stop, trees etc.) blocks the frame, try to change your position to capture a large area of the facade of the building.

• You can additionally take a photo of the parts of the facade where signs and banners are placed with the vertical orientation of the device

• The visual overlap between adjacent frames must be at least 50%.

• Do not try to capture images where there are no facades of buildings or many trees (forest, parks etc.).

Capturing a Typical Street

A sidewalk width of around 5m

• 2 passages

• Lateral step of 3m

• Shooting with smartphone:

  • Landscape 15 photos for each point

Capturing a sidewalk with approx. width of 4m

A sidewalk width of around 3m

• 2 passages

• Lateral step of 1,5m

• Shooting with smartphone:

  • Landscape: 15 photos for each point

Capturing a sidewalk with approx. width of 3m

Pedestrian street

• 2 passages: one with the vertical orientation phone and the other one with the horizontal orientation phone along the central line of the street

• Lateral step of 4m

• Shooting with smartphone:

  • Portrait: 20-25 photos of each point

  • Landscape: 15 photos for each point

Capturing a pedestrian street

Capturing a Narrow Street

Non Pedestrian Narrow street

• Sidewalk width up to 3 meters (non-pedestrian narrow street)

• 4 passages (2 passages at each sidewalk): first passage in LANDSCAPE mode, second passage - PORTRAIT mode

• lateral step: half width of sidewalk

• Smartphone: PORTRAIT (20-25 photos for each point) & LANDSCAPE (15 photos for each point)

Capturing a non-pedestrian narrow Street

Pedestrian Narrow Street

• 2 passages: one with the vertical orientation phone and the other one with the horizontal orientation phone along the central line of the street.

• Lateral step: 3m

• Smartphone: PORTRAIT (20-25 photos for each point) & LANDSCAPE (15 photos for each point)

Pedestrian narrow street

Very Narrow pedestrian Street

• If the street width less than 4 meters – use half-star approach, by making two passages as close as possible with your back to each facade, rotating, but not capturing frames in the area that is directly behind you. Starting and ending shooting at a point with frames that capture both facades of a narrow street (including the one closest to you) Lateral step: 1-1.5 m

• PORTRAIT (about 20 photos for each point)

• You should additionally take a photos of the parts of the facade where signs and banners are placed with the vertical orientation of the device

Very Narrow Pedestrian Street

Capturing a Wide Street

Wide street is the type with a sidewalk width more than 5 meters (or with grass area and flowerbeds)

• You should make as many passages as required (3 and more), using horizontal orientation of the device: first passage at the distance from 5 meters from the building facade (at the border of sidewalk), second – from 7-10 meters (near the road), third and other – from doubling distance in relation to the previous passage, if there is wide area before the road. The distance from the facades to the road might be 10-15 meters and more.

• Lateral step: 4 meters at the first passage from each façade, 6 meters at the next passage, 10 meters at the third passage etc.

Wide Street Example

Capturing a Crossroad

For each corner of crossroad, you should acquire photos at least from 3 points near the road.

Besides, for the crossroad you should try to capture the facades of the both sides of the crossing street. In addition, you have to capture photos of buildings in the corners of the crossroad as if you were shooting a street. In the case of acquiring frames of the crossroad, it is necessary to take into account recommendations for acquiring buildings facades on the street (if the crossroad is wide – you should make as many passages as needed).

Crossroad example

Besides, for the crossroad you should try to acquire both facades (of the both sides of the crossing street). On the left image below – the bad example, because we have not photos with both facades. You must take photos in such a way as to capture the facades on both sides of the crossing street (right image below).

Capturing facades correctly in a crossroad

NOTE: If the cross contains “virtual corner” you should to take photos considering them like real corner.

Capturing a square

In the first passage, acquiring photos is carried out at a distance of 5 meters from the facade of all buildings around the area. The next passage is 10-15 meters from the facades. For every next passage the distance to the facades doubling. The distance between adjacent points in second and all next passages can be increased by 3-5 meters.

Street along the seaside

If you are shooting on a seaside street and there are no objects of interest on seafront, use the half-star approach described in paragraph 2, acquiring frames only in the area from 0 to 180 degrees in the direction of the facade, starting and ending with frames along the street, on which the facade occupies about 30%.

The first passage should be done from the distance 5m, the others – depending on the distance from the edge of the seaside to the facade of the building in accordance with the recommendations for shooting wide streets.