Scale factor gis
- 1. SCALE FACTORS IN PIPELINE ENGINEERING DESIGN Presented by Y.Muthuraman M.Tech PLE(R150214029)
- 2. What is Scale factor ? Scale Factor(SF) = 𝐀𝐂𝐓𝐔𝐀𝐋 𝐒𝐂𝐀𝐋𝐄(𝐀𝐒) 𝐏𝐑𝐈𝐍𝐂𝐈𝐏𝐋𝐄 𝐒𝐂𝐀𝐋𝐄(𝐏𝐒) SF-Scale factor AS-Distance between the two points on Map PS-Distance between the two points in the Earth
- 3. Cartographers Why we need Scale factor ?
- 4. Scale Factor in Pipelines Scale factor differs from one location to another. We need to cover the entire ROUTE OF PIPELINE (From Source Station to Transmission Station) by calculating the Scale Factor which varies with respect to Map Projection terrain or plane or valley or any location.
- 5. Distortion and Scale factor • Longitudes starts from 0 degree meridian line, all the longitudes forming same diameter circles on the earth. • Latitudes starts from 0 degree Equator line, all the latitudes forming the circles, whose diameter goes on decreases, towards North & South pole.
- 6. Distortion and Scale factor Earth has different Circumference(2πr) Distortion Scale factor differs for every latitude •
- 7. Map Projection • A plane is placed tangent to the Earth’s Surface • The points are projected from the centre of the earth to the plane gives us the parallel lines(lattitude). • Earth looks from centre point of view and projected on to the plane and creates the image on chart/map.
- 8. CYLINDRICAL/mercator PROJECTION Cylinder placed around the equator and makes tangent plane. Plane contains parallel lines(line at which cylinder is tangent to equator) and projections of meridians, both maintains the same diameter in all the circles of latitude No distortion in circumference of Earth’s Surface
- 10. Lambert Conformal Projection • Best method for mapping the pipelines mostly preserving the • Maxi. Scale Error of 2.5% Shape of the features Directions of the Route Distances between two points Areas to be located
- 12. Requirements for Scale Factor Pipelines having different scenario Elevation, Compresssor station, buried pipeline , subsea pipeline , forest, roads , streams 1. Positioning of respective elevation 2. Datum point , 3. Latitude coordinate, 4. Longitude coordinate , 5. Eccentricity from parallel lines
- 13. Steps to calculate the Scale factor for Routing the pipeline • Set the Central Meridian in your source station of pipeline. (Eg. Pipeline layed from 12degree WEST to 36 degree EAST) • Set the standard Parallel lines within the site starts from central meridian with the spacing of latitudes 6 degree interval. (Eg. 12W – 36E have the range of 24 degree) So, each latitude spacing = 24/6 = 4 degree of latitude
- 14. Steps to calculate the Scale factor for Routing the pipeline • Convert the latitude degree into Radians for calculating the scale factor(k). • k = ( sqrt(1.0 - e2*sin(lat)*sin(lat))/cos(lat) ) * ( cos(lat1)/sqrt(1.0 - e2*sin(lat1)*sin(lat1)) ) e2 = eccentricity lat = latitude of point lat1 = standard parallel
- 15. Map Scale & True Scale for Routing of Pipeline • Multiply the Scale factor with Map Scale and get the True Scale value of the real world • Scale Factor Distortion is minimized by getting scale factor from Lambert Conformal Map Projection
- 16. X,Y values from Map projection Central meridian value Height and width of routing area By typing the Scale Factor we can change the Scale ratio of :
- 17. Scale factor for different Areas
- 18. Conclusion • Hence the scale factor depends on the type of map projection for different areas, which are going to be considered for routing the pipelines. • Area may be having Elevation , Roads, Stream, Subsea, Terrain, Forest , Protected Areas, Valley , Rivers. • Scale factor varies and also scale distortion is reduced.