The creation of cropped surface required atin surface. After opening the tin surface drawing go to the home the create ground data pannel. Dropdown the surface and select create cropped surface.
The most common digital data of the shape of the earth's surface is cell-based digital elevation models (DEMs). This data is used as input to quantify the characteristics of the land surface.
Fill in the Add XY dialogue box. Select the data table where placed. The data table should be .csv formate. Select the Xyz field. Edit the coordinate system. Then press OK.
All coordinates of the table are drawn on the drawing area in the form of the points.
After the create points in the drawing. Then go to the Arc toolbox.
Arc toolbox>click on 3D Analyst tools>Raster interpolation> click on kriging.
Select the point input point features,z value field, and output surface raster. Press ok.
Then a raster dataset is drawn on the drawing sheet.
you can also create the dem file the use of IDW and spline tool in arc gis
The triangular irregular network (TIN) surface is a consisting of triangular faces of the triangular surfaces in the digital formate. The vertices of the triangles are created from field recorded surveying data. The survey is done by like as Total station survey, GPS RTK,PHOTOGRAMMETRY, etc.
In this article, I describe methods of creating a TIN surface from two software.
HOW TO CREATE TIN SURFACE FROM AutoCAD CIVIL 3D.
Open the AutoCAD civil 3d > Go to the new > Select in the file name- Autodesk Civil 3D (Metric) NCS.
> Select in files of type- Drawing Template(* DWT) > open
Go Home tab>Create ground data panel>Surface>Create surface.
A creation surface dialogue box is open, In the creation surface, the dialogue box changes the name in the dialogue box. like as surface OGL then OK.
After the surface is created, the surface name is displayed in the surface collection in the prospector tree, So that you can perform other operations, such as adding data and editing the surface.
Go to in the prospector tree.
Click on surface>Surface OGL>Click on the surface OGL> Definition>Click on definition>Right click on point files> ADD
After clicking on the ADD an Add point file dialogue box opens. Click the +Add file and select your file in the .csv format.
1.DUMPY LEVEL:-The Dumpy Level is a simple, compact, and stable instrument to determine the elevation of points. The Dumpy level is an optical instrument used in surveying and building to transfer, measure, or set horizontal levels. In this instrument, the telescope is rigidly fixed to its supports and therefore can neither be rotated about its longitudinal axis. Nor can it be removed from its supports. It has greater stability of adjustment than the Y level.
Parts of Dumpy Level
It was invented around the 1830s.
2. AUTOMATIC LEVEL:-The Automatic level is a self-aligning level instrument The fundamental difference between the self-aligning level and the classic spirit level is that in the former the line of sight is no longer leveled manually using a tubular spirit level but is leveled automatically. The automatic level does not require any protection from the sun. Automatic level is a high precision instrument in the forward and backward leveling it has the error between +- 0.5 to 0.8 mm per km. The time required for leveling work is about 50% of that required with ordinary level. The accuracy of a single measurement is increased by an erect telescope image, the leveling rods with erect figures in proper sequence, freedom from fatigue, the possibility of forgetting to get the bubble in the center as well as simple and quick means of operation. The external influences like marshy ground, rain, wind, sun, loss of light due to clouds, magnetic fields, continuous vibration, transport vibrations, have no influence on the leveling work. The level can be used on medium and large-sized projects and setting bench marks of the 3rd to 1st order.
Meridian is the line of reference from which the bearing of the line is measured. There are three types of meridian. OR The imaginary vertical plane passing through the magnetic axis of the geomagnetic is called the magnetic meridian.
Magnetic meridian. The direction indicated by freely suspended and properly balanced magnetic needle, unaffected by local attraction force is called magnetic meridian, and the horizontal angle made with the object or line is called magnetic bearing. It is expressed in degrees minutes and seconds, to showing the magnetic meridian which device is called the magnetic compass. The other method is also used for showing magnetic meridians like gyroscopes, magnetometers, and GPS receivers.
The compass consists of (i) A magnetic needle (ii) A graduated circle (iii) A line of sight
There are three types of compass in common use.
1. The prismatic Compass:- The prismatic Compass may be held in the hand, but for better result, it is usually mounted on a light striped which carries a verticle spindle in the ball and socket joint to which the box is screwed. By means of this arrangement, the instrument can be quickly leveled and also rotated in a horizontal plane and clamped in any position.
The Surveyor's Compass was formerly much used in land surveying, but now it is little used.
The main difference between prismatic compass and surveying compass is east and west quadrants to reverse to each other.
The nature of has magnetic needle is aligned with the local magnetic meridian, then It is of great use in engineering for directional purposes. It is also used for finding the difference between the true meridian and magnetic meridian in surveying and mapping.
Use of magnetic meridian
1. To find the true meridian:- If you want true meridian or true north of a point then easily determined the true meridian by the use of magnetic declination which is given on the map.
2. For finding bearing of line:- If you want magnetic bearing of a line. the easily determined the bearing of line.
3. In underground mine surveying where the GPS is not working properly.
The national grid is a common reference point throughout the country with reference to the single prime meridian coincident with the point of origin at Greenwich.
The grid reference system of the map is the defined location in the map in the geographical coordinate system. The surface of the earth has nature in curved it is impossible to show on flat paper with the parallel meridian. It is shown on the map to a plane grid system coordinate system is referred to as a map projection.
The national grid reference system is different from the geographical coordinate system. It is referred to in the cartesian coordinate system. The grid reference system has required a datum for measuring the distance in a coordinate system.
The datum is defined as the reference datum is used to describe the location of unknown points on the earth.
The no of various datum is used for measurement. In India there are generally two datum is used for mapping WGS1984 and Everest 1956 or India Nepal datum. Now a day survey of India used Datum WGS 1984 and projection UTM.
`Projection is used to defined as the curved surface of the earth or part to represent a flat surface
There are three types of projection used in the mapping.
Conic projection
Cylindrical projection
Planar projection
India used generally two types of projection Lambert conformal conic projection and Universal Transverse Mercator(UTM).
1. WGS1984 DATUM
The National Grid is started 500 km by 500 km squares and has 25 squares. All squares are denoted by an alphabet from A-Z.
500 km grid reference
Each of these 500 km squares is then subdivided into a no. of squares 25, 100 km by 100 km squares, again each with a letter of the alphabet A-Z. It has a scale of 1:250000
100 km grid
It is represented by two alphabetical letters
The 100 km square is now divided by 100 in 10km by 10 km squares. These squares is represented by 0 to 99 numbers.
10 km squares grid
Now 10 square is divided into 1km by 1km squares & it has a scale 1:50000.
1 km by 1 km square grid map
How To Read National Grid reference numbers
In the National Grid Reference System, there are two types of numbers in use easting and northing. The number going toward the east is called the eastward number and the number going toward the north is called the northward number.
The digits used in locating a point as national grid reference numbers.
Ten digits..........23371 06519.....Locating a point within a 1m square
Eight digits.......2337 0651..........Locating a point within a10 m square
Six digits...........233 065........... Locating a point within a 100m square
Four digits.........23 06................Locating a point within a 1 km square
Two digits.........2 0 ....................Locating a point within a 1 km square
Generally used four figure and six-figure grid reference.
Four figure reference grid
In the above picture grid reference of
1=18 45
2=19 45
3=18 44
4=19 45
Six-figure grid reference
Grey box grid reference=187 448
Red dot grid reference=185 443
WHAT- IS- THE- NATIONAL- GRID -REFERENCE -IN- THE -MAPPING
In the above picture, one location is marked ⛰ Dhandhpur. Dhandhpur is located between 258 km and 259 km in the eastward direction and is located between 2726 km and 2727.
Then the grid reference on UTM will be 2584 27264.
WGS 1984 coordinate of Dhandhpur = Langitude=72°36'48.207" Latitude=24°38'1.318"
The Indian National Grid system uses the Everest Spheroid as a reference surface. It was originally defined in 1830 by Colonel George Everest (Surveyor-General Of India from 1830 to 1843) and updated in 1956. Kalianpur (Madhya Pradesh ) was chosen as the initial point of origin.
It is a local datum. The Centre of this reference surface is estimated to about 1 kilometer off from the center of mass of the Earth.
India Nepal datum the area of covered in nine zones.
Grid reference zone
1. Zone0:-India and Pakistan North of 35°35' North
2. Zone IA:- India and Pakistan 28°N-35°N
3.zone IB:-Unknown parts of china.
4. ZoneIIA:-India21°-28°N & west of 82° and Pakistan south of 28°N
5.Zone IIIB:-Complete Bangladesh, India North 21°N & East of 82° and Myanmar North of 21°N.
6. Zone IIIA:- India 15°N-21°N.
7.ZoneIIIB:-Myanmar 15°N-21°N
8.Zone IVA:-India south of 15°N
9.Zone IVB:-Myanmar south of 15°
Note: The Zones area for the Zones is from freely available sources and not the official specifications.
In the above picture
WGS 1984 coordinate of Dhandhpur = Langitude=72°36'48.207" = Latitude=24°38'1.318"
Land surveying is the process of determining the features and boundaries of a property.
It is also used for
Location of the points on the earth's surface.
The development of the land.
To determine encroachment.
Engineering, construction, archaeological, and mining projects, etc.
For government needs.
And any other requirements for the government and the public.
There are many types of instruments and methods is used in land surveying, But after came GPS in surveying then GPS survey is more accurate than hand measurement surveying methods.
The advantage of land surveying with GPS.
The fundamental of land surveying is the exact position of the point on the earth's surface. It is possible only surveying with GPS.
In the GPS method, the coordinates give very precise than other methods of survey due to human, instrumental and natural error.
GPS reading gives three coordinates which are important for land development and site planning work.
GPS survey is not completely replaced of theodolite, total station, and other survey equipment due to non-availability of satellite signals near tree and building.
Methods of the land survey with GPS
GPS or GLOBAL POSITIONING SYSTEM is a satellite-based navigation system. The no. of satellite communicates with GPS data receiver. The GPS receiver receives the data from the satellite in the form of the longitude, latitude, and height of the GPS receiver.
There are many methods available for surveying land with GPS.
1.STATIC GPS BASELINE METHOD:- This method is used to measure the baseline according to surveying done by triangulation. In this method, a minimum of three known and unknown points marked on the ground with the flag or peg. Set the two GPS receivers over the two marked points. Start the GPS to communicate the satellite. The observation took at least 20 minutes from both GPS receivers, then receivers collect data simultaneously. The time of observation depends on the distance of the baseline and requirements of accuracy.
shift the one GPS receiver and set on the other base point and took the observation. The process continues until requirements are completed. Process the data to determining the difference in longitude, latitude, and height in the software.
Advantage of statics GPS recevers
Due to a long period of data collection give more accurate data.
The data collections are not affected due to the visibility of each other baseline points.
2.REAL-TIME KINEMATIC OBSERVATION:-In this method, the receiver remains in one position over a known point. The base station and another receiver move between positions of the rover station. The position of the rover can be computed and within a few seconds. Using a radio link.
Continuously operating reference stations. In this method, the GPS receiver is permanently installed in the location as a starting point.
In the above picture, The GPS receiver set on the base station on the trijunction point, and another rover receiver take the data on the boundary of the plot.
3.Continuously Operating Reference Station(CORS).:- In this type of survey, the GPS receiver is permanently fixed on the starting point of location or government department. The survey data is collected with a combination of CORS.
4.ABSOLUTE METHOD OF OBSERVATION:- In this method, the single Gps receiver is fitted over the station, and data is collected on the basis of resection. The accuracy of data depends on the accuracy of time and position of the receiver. In this method minimum of four GPS is required during observation.
The digital elevation model in GIS describes as the elevation information of the earth's surface(relief), moon, and asteroid in the digital format. This digital format is called the digital elevation model(DEM).
The DEM is a computerized representation of the earth relief in different formate such as triangulated irregular networks (TIN), regular grids, contour lines, scattered data points. The digital elevation model is presented by wireframe model and image matrix.
The currently available digital elevation model exhibit discontinuities with respect to coverage resolution, accuracy, and reference datum, they are also inhomogeneous because they are derived through different methods. The currently best, most comprehensive, global data set comes with a horizontal resolution of one kilometer and elevation accuracy of 100 meters.
The no. of methods available for obtaining elevation data for DEM.
(a) LIDAR:-Lidar is a method for determining ranges by targeting an object with a laser and measuring the time for the reflected light to return to the receiver lidar can also be used to make a digital 3D representation of an area on the earth surface and ocean.
(b) Radar:-Radar is a detection system that uses radio waves to determine the object's range, angle, or velocity. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles.
(c)Ariel survey:-Aerial survey is a method of collecting imagery data by using airplanes, UAVs, and other aerial methods.
(d)Real-Time Kinematics GPS:-TheGlobal Positioning Systemis satellite-based navigation and surveying system to determine precise position and time.
It is work in three segments. 1. Space Segment. 2. Control Segment. 3. User Segment
(e)Topography Survey Map:-Topography survey is the process of determining the position, both in plan and elevation of the natural and artificial features of the region with conventional symbols.
(f) Total Station survey:-Total Station is an electronic or optical instrument for measure angle, distance, and coordinates. It is a combination of transit theodolite with an electronic distance meter.
(g) Doppler Radar:-A Doppler radar is a specialized radar that uses the doppler effect to produce velocity data.
Relation between DEM and Geographical Information Systems
DEM can be used together with other spatial data, image data in a geographic information system. The DEM provides a basic spatial reference system to the GIS spatial data set images or vector information can automatically be draped over and integrated with the DEM for more advanced analysis.
Application of data elevation model
Nowadays DEM has played an important role in the analysis result, product development, and decision making.
1. Scientific application:-The scientific application of DEM is about the surface of the earth.
DEM has used for the study of topography and the shape of the earth. Another area of application is global land cover classification, precise mapping of and classification of the earth surface.
A. Climate impact studies
B. Water and wildlife management
C.Geological and hydrological modeling.
D. Geomorphology and landscape analysis.
E. Mapping purposes
F. Educational programs.
2. Commercial application:-Commercial applications are more market and business-oriented applications related to the sale and distribution of DEM and DEM products.
A.Telecommunication
B.Air traffic routing and navigation
C. Planning and Construction
D.Hydrological and meteorological services.
E.Geo-coding of remote sensing
F.Market of multimedia applications and computer games.
3.Industrial Applications:-For industrial applications digital elevation models are used for the development of the market-oriented product technology, improved services and to increase the economic outcome of productions.
A. Telecom
B.Telimatics
C.Mining
D.Engineering
4.Operational Applications:-The geo-information data is used in all types of government planning, administration, and management. The DEM is used for the improvement of planning and management of natural resources and within the area of regional planning, environment protection, hazard reduction, military, and other security-relevant application, insurance issues, health services, agriculture, forestry, and soil conservation.
The data structure for a continuous surface model of three-dimensional shape. The surface model is used for creating a grid at regular intervals, random points, contour lines, and surface profile making.
Data are units of information. The data are collected through observation. Data are used in scientific research, engineering, surveying, transport, business management, finance, governance, etc. The Data are measured, collected, reported, and analyzed. The data are visualizations and produced such as graphs, tables, and images. In the GIS the data stored information about the world. In the GIS the data are collected through thematic layers and linked with the geographical information system.
There are two types of basic data using in the GIS.
1. Spatial Data.
2.Attribute Data.
1. Spatial Data:- Spatial data describe as which has the absolute and relative location of a geographic feature on the earth's surface. In the GIS spatial data has physical dimensions on the earth. The spatial data explained in the form of point, line, area, and surface on a map. The spatial data explain in tabular form, a geographical map, a digital map, and a remotely sensed map. The spatial data are stored in a graphic file and managed by the file management system
. The spatial data are represented in two basic models in the GIS.
(i) Vector Data Model
(ii)Raster Data model
(i)Vector Data Model:- In the vector data model location of geographic feature is stored in the form of vectors or dimensional lines. All vertex of the geographic feature has ( x,y) coordinates or longitude and latitude.
One pair coordinates and vertex represent a point feature. The polygon feature contains no. of closed coordinate pair and vertices. Vector lines are consist of a string.
Vector data map
(ii) Raster Data Model:-Raster data model is defined as the model that incorporates the use of grid cell.
In the raster model data of geographical area is divided into row and column. The size of a cell depends on the tessellated data structure based on the data accuracy and the resolution needed.
point raster
polyline raster
polygon raster
2.Attribute Data:-Attribute data is used in GIS for describing the map features. Any geospatial data has three major components such as position, attributes, and time. The attributes data are linked with spatial data or geometric data.
The storage and management of GIS data are four models.
(I) Tabular:- In the tabular model the data are stored in sequential data files with fixed formates.In this model the location attribute values in a predefined record structure. It has limited indexing capability for records.
TABULAR MODEL
(II) Hierarchical Model:-The hierarchical dataset organizes data in a tree structure. Data is structured downward in the hierarchy of tables. Any level in the hierarchy can have unlimited children. But any child can have only one parent. A hierarchical model is a tree structure. The advantage of the hierarchical model has a high-speed dataset and ease of updating.
Hierarchical Model
(III) Network Model:-The network database organizes data in a network. The network DBMS have not much more acceptance in GIS than the hierarchical DBMS. The more powerful structure for representing data relationships allows for more realistic modeling of geographic phenomena.
(IV) Relational Model:-The relational database organizes the data in the table form. Each table is identified by a unique table name, and it is organized by rows and columns. Each column within a table also has a unique name. There are many different DBMS designs, but the relational design has been the most useful in a GIS. In the relational design, data are stored conceptually as a collection of tables. Common fields in different tables are used to link them together.
