In this article we will learn various concepts related to maps, mosaics and photographs. We will also compare and list the differences present between map and mosaic.
What is a Map?
Map is a graphical representation of an area, where all details are present at a specific scale.
There are different types of maps classified based on several criteria.
What is a Photograph?
Photograph can be defined as an instantaneous record of features and objects present in an event. In a photograph scale is not constant throughout.
You may Read: Different types of Aerial Photographs
What is Mosaic?
A mosaic is a photographic product. It is prepared by cutting and removing the common area in one of the 2 adjacent photographs taken during the aerial photography, then joining them together. Compared to photograph a mosaic represents large amount of area.
Types of Mosaics:
Mosaics are mainly classified into 2 types as given below.
- Controlled Mosaics
- Uncontrolled Mosaics
Controlled mosaics contain ground control points. These points are marked at various locations on the photograph and are transferred into the mosaic while preparing. These ground control points help in understanding or estimating the distance between various locations on the mosaic.
Uncontrolled mosaics doesn’t contain any control points. The photographs are simply joined together for the sake of continuity only. It is normally used for understanding or visually inspecting various features of the terrain. Measures cannot be made from this type of uncontrolled mosaics.
A map and mosaic have many contrasting characteristics. Most of such differences are also present between mosaic and map.
Following section distinguishes between map and mosaic.
Differences between Map and Mosaic:
- Map contains uniform scale through out. Whereas mosaic doesn’t have a fixed scale, it varies with location.
- Map is created using orthogonal projection of rays. As mosaic is photographic product, one can say a mosaic contains the rays drawn in perspective fashion in each segment of photograph used for creating it.
- Map contains symbols and labels. A raw mosaic doesn’t show any labels or symbols. It shows terrain as a whole.
- Map contains coordinates and assumed data. Mosaic shows only real features of the area.
- Mosaic can be prepared in very less time compared to map.
- Mosaics are less costly and requires less resources compared to map.
- A mosaic can be easily understood by layman than map, as symbols are not meaningful to such people.