Wednesday, 31 January 2018

2010 to Onward – The Open Source Explosion

2010 to Onward – The Open Source Explosion

With users getting accustomed to GIS software, this has sparked a new revelation in GIS – an open source explosion. Amazing projects like QGIS are providing any user with a computer with GIS software.

Processors are now in gigahertz. Graphics cards are crisper than they’ve ever been before. We now think of GIS data storage in terabytes. It’s no longer megabytes.

GIS data has become more ubiquitous. TIGER data, Landsat satellite imagery and even LiDAR data is accessible to download for free. Online repositories like ArcGIS Online store massive amounts of spatial data. It’s a matter of quality control and fitting it for your needs.

The range of commercial GIS software products out there seem endless.

But what stands out is the big shift of GIS users building their own GIS software in an open, collaborative way. This software is made available to the public and is called open source. The big plus is: they are for public use at no cost.

Open source is becoming mainstream today. We are gradually entering an era of open source GIS software. More light is shining on QGIS than ever before. Even though, there will always be a place for commercial GIS software. Software companies like Esri provide solutions to practically any spatial problem that exists today.

1990 to 2010 – User Proliferation

1990 to 2010 – User Proliferation

Users are starting to adopt GIS technology in different ways. Classrooms, businesses, governments around the world are starting to harness digital mapping and analysis.

All the ingredients were ready for the infiltration of GIS to the people:

Cheaper, faster and more powerful computersMultiple software options and data availabilityThe launch of new satellites and integration of remote sensing technology

1990 to 2010 was the period in the history of GIS when it really took off.

But advancements in the technology have surpassed the average user. GIS users didn’t know how to take full advantage of GIS technology. Companies were hesitant to adopt GIS software. Countries didn’t have access to topographical data.

But over time, these issues were laid to rest.

Gradually, the importance of spatial analysis for decision-making was becoming recognized. Slowly, GIS was being introduced to classrooms and companies. Software was able to handle both vector and raster data. With more satellites being launched into orbit, this data collected from space could be consumed in a GIS.

This in unison with the availability of global position systems gave users more tools than they’ve ever had before. Like the flick of a switch, GPS selective availability was turned off. Suddenly, accuracy has changed from the size of an airport to the size of a small shed. GPS has led the way to great innovative products like car navigation systems and unmanned aerial vehicles.

The floodgates for GIS and GPS developments began opening. This brings us to our next stage of development in the history of GIS: the open source explosion.

1975 to 90 – GIS Software Commercialization

1975 to 90 – GIS Software Commercialization

As governments realized the advantages of digital mapping, this influenced the work of the Harvard Laboratory Computer Graphics. In the mid-1970s, Harvard Laboratory Computer Graphics developed the first vector GIS called ODYSSEY GIS. Esri’s ARC/INFO used the technical framework from ODYSSEY GIS and this work led to the next stage of development in GIS – software commercialization.

In the late 1970s, memory size and graphics capabilities were improving. New computer cartography products included GIMMS (Geographic Information Making and Management Systems), MAPICS, SURFACE, GRID, IMGRID, GEOMAP and MAP. In the late 1980s, this segment of GIS history was marked with an increasing range of GIS software vendors.

One of these GIS software vendors was Esri – which is now the largest GIS software company in the world. In 1982, ARC/INFO for minicomputers was launched and in 1986, PC ARC/INFO was launched with the production of the Intel microcomputer. Esri is now the world’s leading experts in GIS software development and it has played a key role in the history of GIS.

At this point in the history of GIS, it also gained steam with some of the first conferences and published work. The first GIS meeting in the UK was in 1975. It included a small crowd of academics. The first Esri conference was in 1981 and attracted a crowd of 18 participants. GIS consultancies started sprouting. Roger Tomlinson first used the term “Geographic Information System” in his publication in 1968 “A Geographic Information System for Regional Planning”. That was a real lonely time for GIS.

But all of us users have made GIS what it is today. Especially for the next time period:

1960 to 75 – GIS Pioneering

1960 to 75 – GIS Pioneering

The early 1960 to 1980s was really the time period of GIS pioneering.

The pieces were coming together with advancements in technology:

Map graphics as outputs using line printers.Advances in data storage with mainframe computers.Recording coordinates as data input.

These initial developments in the world of computing is what propelled GIS its next step forward. But what GIS really needed was a brilliant mind to put the puzzle pieces together.

Enter Roger Tomlinson – the father of GIS.

It was during Roger Tomlinson’s tenure with the Canadian government in the 1960s when he initiated, planned and directed the development of the Canadian Geographic System (CGIS). This was a key time in the history of GIS because many consider CGIS as the roots of Geographic Information Systems. CGIS was unique because it adopted a layer approach system to map handling.

Great discoveries and improvements invariably involve the cooperation of many minds. I may be given credit for having blaze the trail of GIS. But when I look at the subsequent development, I feel the credit is due to others rather than just myself.
-Roger Tomlinson

Because of the vast amount of territory Canada occupies, the idea for a Canadian Land Inventory was developed in 1964. But it wasn’t until 1971 that it became fully operational.

The Canadian Land Inventory used soil, drainage and climate characteristics to determine land capability for crop types and forested areas. It quickly recognized that accurate and relevant data was vital to land planning and decision making. Over the years CGIS had been modified and improved to keep pace with technology.

The CGIS wasn’t the only group adopting GIS:

The US Census Bureau were early adopters of some of the core principles of GIS. It was the pioneering work by the US Census Bureau that led to the digital input of the 1970 Census using the data format GBF-DIME (Geographic Base File – Dual Independent Map Encoding).

GBF-DIME became a file format that supported digital data input, error fixing and even choropleth mapping. Using this format, the US Census Bureau began to digitize Census boundaries, roads and urban areas. This was a huge step forward in the history of GIS.

The Ordnance Survey in the UK also started their routine topographic map development. To this very date, the Ordnance Survey is still producing many different GIS data products including every house, every fence, and every stream in every single part of Great Britain.

At this point in the history of GIS, it was in its pioneering stage. It was still on its training-wheels beginning to be fostered by only a select few national agencies around the world.

Where did GIS begin

Where did GIS begin?

Mapping has revolutionized how we think about location. Maps are important decision making tools. They help us get to places. And they are becoming more immersed in our everyday lives.

But where did it all begin?

Advancements in GIS was the result of several technologies. Databases, computer mapping, remote sensing, programming, geography, mathematics, computer aided design, and computer science all played a key role in the development of GIS.

Today, we’ll uncover some of the key moments in the history of GIS that has shaped it what it has become today:

Paper Mapping Analysis with Cholera Clusters

Dr. John Snow used mapping to illustrate how cases of cholera were centered around a water pump. Many people thought the disease was propagating through the air. However, this map helped show that cholera was being spread through the water.

The history of GIS all started in 1854. Cholera hit the city of London, England. British physician John Snow began mapping outbreak locations, roads, property boundaries and water lines.

When he added these features to a map, something interesting happened:

He saw that Cholera cases were commonly found along the water line.

John Snow’s Cholera map was a major event connecting geography and public health safety. Not only was this the beginning of spatial analysis, it also marked the start of a whole field of study: Epidemiology – the study of the spread of disease.

To this date, John Snow is known as the father of epidemiology. The work of John Snow demonstrated that GIS is a problem-solving tool. He put geographic layers on a paper map and made a life-saving discovery.

Thursday, 11 January 2018

Roles and Work of Surveyor in Construction

Roles and Work of Surveyor in Construction


Roles and Work of Surveyor in Construction

The surveyor is the person who is supposed to make precise measurement that will identify the boundary. Surveyors help in providing unique contours on the surface of the earth which will let the engineers to make maps and construction projects.

Table of Contents [hide]


1 What are the Duties of a Surveyor?


2 Work Characteristics of Surveyor

2.1 Field Work Conducted by Surveyors

2.1.1 The filed note consists of three parts:


2.2 Office Works Done By surveyor


2.3 Instruments Care and Adjustments by Surveyors


What are the Duties of a Surveyor?

The following are the duties of a surveyor.

The surveyors have to measure the distance and the angles between specific points on the earth surface.


Based on reference points, certain important features points are located by traveling.


Detailed research is carried out on the records related to the land, survey, and the titles of the land.


The boundary lines are to be located by searching for the past boundary present in the site.


The surveying is conducted and the obtained results are recorded. Later they are verified for accuracy and corrections.


Based on the surveyed records plots, maps, the respective reports of the surveyed site is prepared.


The findings obtained from the surveying is presented to the clients and the respective government agencies.


The official land needs and water boundaries are established. These are established either for lease or deeds.


Work Characteristics of Surveyor

The works performed by the surveyor can be divided into three different parts. They are:

Field Work


Office Work


Instruments Care and Adjustments


Field Work Conducted by Surveyors

As mentioned in the duties of surveyor, he has to determine the points and their respective distances and angles which have to be recorded in the form of field notes.

The operations involved in the field works are:

Initial establishment of benchmarks and all the stations as the reference. Based on these operations the horizontal and the vertical control is established.


The angles between the survey lines created have to be measured.


All the details of the survey are explained and located based on the stations and the lines between the stations. The details are the streams, buildings, milestones, streets and any other natural or man-made features present in the area surveyed.


For the constructions works related to buildings, culverts, sewers, bridges, and water supply schemes the lines have to set out and the grades are established by the surveyors.


Height or the elevation of certain points are determined by surveying by the surveyor. Or in either case, specific points have to be established in required elevations.


Carrying out topographic surveying. This is the surveying of contour of the given land which involves both vertical and horizontal controls.


Parallel lines and perpendicular lines have to be established.


The inaccessible points have to be measured.


To conduct survey past the obstacles. Many miscellaneous field works based on the trigonometric and the geometric principles have to be conducted.


Determination of the meridian, latitude, and longitude or to determine the local time by carrying out observations on the sun or a star.


When dealing with field works, it is very important to understand the importance and the features of Field Notes.

Field notes are written notes that are prepared when the field work is carried out. There are situations when the whole precision of the survey and the field work becomes futile if the value recorded is wrong.

Hence the quality and competency of a surveyor’s work is more reflected in the field record when compared to the basic elements of surveying he performed.

The prepared field notes must be eligible, comprehensive, and Concise. The values and remarks have to be written in clean, clear plain letters and figures. There are certain basic rules to be keep while maintain a field note. They are:

As soon as the observations are made, the values are recorded in the field book


The pencil used must be sharp 2H or 3H. Never make use of a soft or ink pencil


It is recommended to have simple style of writing that must be consistent


Try to use liberal number of sketches


Each day of survey work must end up with a brief note. This must have the title of the work, the date of survey, the conditions of weather, the personnel involved, the list of the instruments and the equipment used.


It is recommended not to erase. If a mistake is made, rule through the mistake and the corrected value is marked above it.


The daily notes created must be signed.


The filed note consists of three parts:

1. Numerical Values

All the recorded measurements like length, angles, staff readings, offsets are recorded in this column on the field book. All the figures that are significant must be recorded correctly. Values nearest to 0.01 must be recorded. A value observed as 342.30 must be written as same and not as 343.3.

2. Sketches

The sketches will resemble the outlines, the topographic features, and the locations relative to each other. These are not made to the scale. If we plan to place the measurements on the sketches, correct belongings must be made while marking it. Always make a sketch which makes the interpretation easier. This must avoid maximum confusion. The sketches must be large, open as well as clear.

3. Explanatory Notes

All those that cannot be conveyed through the values and the remarks must be written in the explanatory note section. These remarks will help to proceed the later works.

Office Works Done By surveyor

Drafting, computing, and designing are the office works that have to be performed by the surveyor.

The drafting performed consists of the preparation of plans and the sections. These must be plotted to the measurement and to scale and prepare the topographic maps.

The computing process is done in two cases. Initially, it can be done for the plotting. Secondly, it can be constructed for the determination of the areas and the volumes.

Instruments Care and Adjustments by Surveyors

If there is good experience in handling the equipment, the works can be carried out with great experience and precision. This knowledge on handling will make us understand the limitations of the instrument and can take proper care of these equipment.

There are many instruments like the level, theodolite, etc. that requires great care with delicate handling. There are many delicate parts in the instruments, if any of the parts get affected, it will bring total complaint and total loss.

The relative positions of the instruments must be checked while taking out the instrument and during its placement back after the use. Straining the parts of the instrument will result in the incorrect measurements.

The precautions that must be taken are:

The instrument must not be lifted by holding the telescope or the circular plate. We must hold the foot plate or the leveling base.


The movement of the instrument from one place to another must be carried out by placing it on the shoulder. All the clamps are set tightly.


When not in use, the lens must be covered.


Setting up the instrument on a smooth floor without any kind of precautions must be avoided.


The instrument must not be exposed to dust and dampness or direct sun rays. A waterproof cover can be used to cover and protect it.


Not leave the instrument without any guard.


The steel tape after use must be cleaned and kept dry. While measuring, vehicles are not allowed to move over it.


In case of compass instrument, the compass must not be allowed to swing without any need. This is lifted off the pivot when not in use.