ALI HAIDER

1. DATA COLLECTION AND TECHNIQUES
Department of Zoology
University of Narowal

2. Primary data Capturing techniques
1. Remote Sensing
“Remote sensing is a technique used to derive information about the physical,
chemical, and biological properties of objects without direct physical contact.”
Remote sensors can be used for this purpose ( Capturing Primary data). Remote
sensors can be either passive or active
1. Passive sensors respond to external stimuli. They record natural energy that is
reflected or emitted from the Earth's surface. The most common source of radiation
detected by passive sensors is reflected sunlight.
2. In contrast, active sensors use internal stimuli to collect data about Earth. For
example, a laser-beam remote sensing system projects a laser onto the surface of
Earth and measures the time that it takes for the laser to reflect back to its sensor.

3. Remote Sensing Applications
Remote sensing has a wide range of applications in many different fields:
1. Coastal applications: Monitor shoreline changes, track sediment transport, and map
coastal features. Data can be used for coastal mapping and erosion prevention.
2. Ocean applications: Monitor ocean circulation and current systems, measure ocean
temperature and wave heights, and track sea ice. Data can be used to better understand
the oceans and how to best manage ocean resources.
3. Hazard assessment: Track hurricanes, earthquakes, erosion, and flooding. Data can
be used to assess the impacts of a natural disaster and create preparedness strategies to
be used before and after a hazardous event.
4. Natural resource management: Monitor land use, map wetlands, and chart wildlife
habitats. Data can be used to minimize the damage that urban growth has on the
environment and help decide how to best protect natural resource

4. 2. Aerial photography
The term "photography" is derived from two Greek words meaning "light" (phos) and
"writing" (graphien). Aerial Photography means photography from the air. Aerial
Photography is one of the most common, versatile and economical forms of remote
sensing and it was the first method of remote sensing.Aerial photography is equally
important in medium-to large-scale projects.
 Photographs are normally collected by cameras, aircrafts or any other flying object.
 Aerial Photographs are usually collected on an adhoc basis.
 Aerial photography is used in cartography, land-use planning, archaeology,
environmental studies, commercial advertising, and other fields.
 Can provide stereo imagery

5. Advantages:
1. Consistency of the data
2. Availability of systematic global coverage
Disadvantages:
1. Resolution is often too coarse
2. Many sensors are restricted by cloud cover

6. 3. Surveying
Surveying is a technique and science of accurately measuring the distances and angles
between different points, on the surface of Earth.
Surveying equipments are theodolite, measuring tape, total station, 3D scanners,
Traditional equipment like theodolites have been replaced by total stations that can
measure both angles and distances.
A total station is an electronic/optical instrument used in modern surveying and
building construction that uses electronic transit theodolite in conjunction with
electronic distance meter (EDM).
Ground survey is a very time-consuming and expensive activity, but it is still the best
way to obtain highly accurate point locations.
Typically used for capturing buildings, land and property boundaries, man made holes
and other objects that need to be located accurately.

7. Theodolite

8. 4. LiDAR (Light Detection and Ranging)
Lidar is a surveying method that measures distance of a target by illuminating the
target with laser light and measuring the reflected light with a sensor.
 Relatively new technology that employs a scanning laser rangefinder to produce
accurate topographic surveys.
 Typically carried on a low-altitude aircraft that also has an inertial navigation
system and a differential GPS to provide location.
https://www.youtube.com/watch?v=uSESVm59uDQ&feature=emb_logo
https://www.youtube.com/watch?time_continue=64&v=EYbhNSUnIdU&feature=emb_logo

9. Secondary Data Sources
 Scanning coverts paper maps into digital format by capturing features as
individual cells, or pixels, producing an automated image. Maps are generally
considered the backbone of any GIS activity. These paper maps have to be first
converted into a digital format usable by the computer.
 Three main reasons to scan hardcopy media are:
1. Documents are scanned to improve access, provide integrated database storage, and
to index them geographically.
2. Film and paper maps, aerial photographs, and images are scanned and
georeferenced so that they provide geographic context for other data.
3. Maps, aerial photographs and images are scanned prior to USE

10. Scanner

12. Capturing Attribute data
• An attribute is a property or characteristic of an entity. Attribute data is
information appended in tabular format to spatial features. The spatial data is
the where and attribute data contains information about the what, where, and
why.
 Attribute data provides characteristics about spatial data.
 Attributes can be entered by direct data loggers, manual keyboard entry

14. Managing a data collection project
Most of the general principles for any GIS project apply to data collection:
i. the need for a clearly articulated plan, adequate resources, appropriate funding, and
sufficient time.
ii. A further important decision is whether data collection should use in-house or
external resources.