Convex or Concave (MCP) in QGIS?

Many times in the Home range analysis (radiotracking data) , we want minimum convex polygon. Although this method includes more area than is actually required for analysis.  Read more in Analysis of Wildlife Radio-Tracking Data by  Gary C. White, Robert A. Garrott. This is where minimum concave polygon comes to our rescue. Making minimum convex hull and concave hull is possible in QGIS.

1.Goto Geoalgorithm> Vector geometry tool> Concave Hull

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The polygon is formed on the basis of cluster of point nearby. It reduces the actual captured area,rather than combining the holes in points placement.

2. Goto Geoalgorithm> Vector geometry tool> Convex Hull

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For the same set of point in image no 1, Convex hull is created.

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the resulting Concave (inner polygon) and Convex (the outer polygon) is shown in following image.

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to add XY coordinate, view in attribute table in QGIS

IF a file is provided in which one wants the XY coordinate in attribute, first step is to be sure in what projection it is. Whichever projection, coordinate of same will be added.

This is single step process.

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1.open the point layer. Goto> Vector>Add co-ordinate to points

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2. Select the point layer and give save output. You can save as temporary file too.Also if you want to run many files as batch, you can select that feature too.

 

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The output file will have XY coordinate in attribute table.

the bird delight

Mussorie is a delight for humans for the cool weather and pleasant walk in the mountain. But it is also a perfect playground for many birds. More so the way from Doon valley to Mussorie provide enchanted encounters of birds, butterflies and many more interesting small survivors. The heavy traffic and changing weather is creating problem for the hill station and its musical residents. Post a rainy night, I decided a trek to the Mussorie to explore bird which on vehicle gets too difficult and annoying.

From Rajpur road, a famous shop Hathi tea stall marks the identifying location if the trek. If one cannot figure out old route to Mussorie from Dehradun ask people about this shop! Its right next to the Christian Retreat and Study Center in Rajpur. the trek opposite to that will take you to Jharipaani and trek to Mussorie . The old toll of British India time is present ahead of which is  heritage route to Mussorie.

walking up the trail we encountered many birds and yes lots of lantana bushes. The prominent bids on the trek were Rufous sibia, Egyptian vulture,streaked laughing thrush, purple sunbird, crimson sunbird, oriental white eye. Further up on the trek as we reach Barlogunj, we encountered great barbet, Bar-tailed Treecreeper,Blue-throated Barbet,Chestnut-bellied Rock-Thrush,Russet Sparrow,Green-backed Tit,Black-lored Tit,Thick-billed Flowerpecker .

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Barlowganj is a small settlement which is mid-way to Mussorie. The famous location is Jharipani of this area where people can trek from the main town itself. Some nice place to stay and walk around if your are looking for peaceful environment. One could see the real birds as well as painted ones in the town and flowering of rhododendron can be witnessed in this small settlement. Bus travelling to this route is not very frequent.

The trek  was exactly how many kilometers we could never tell. Rain, running after birds, exploring trees and talks amongst the exploration of route might have added to 4-5 km extra to the total trek. We concluded that we might have walked some 12-13 km from Rajpur road to Mussorie in 7 hours. But all the bird sighting and beautiful landscape view made it a memorable and worthwhile trek.

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Will explore another route in the hills, till then happy birding!

the camouflaging one

the scaly thrush as observed in first week of march in Dehradun. A peculiar “khrrr khrr” sound drew me to investigate and found the bird sitting on the leaf litter. since it was first shower of winter, observing the camouflaged bird in brown and green leaves was difficult. the observation was made in slightly drizzling afternoon.

To convert multiple kml file (googleearth layer) to shapefile with QGIS.

 

If you have multiple point, polygon in kml format we can use QGIS to convert all as shapefile in single step.

  1. Following is example of kml point files, b1, b2, b3, b4, b5, b6kml-points
  2. Open Qgis Toolbox
  3. Goto  Geoalgorithms>Vector>General Tools> Save selected feature. Right click on it and select execute as batch processpicture1

 

  1. In the window of Batch processing , select your KML (google earth layer) from file system. The + sign is to increase the number of rows if you have many kml files.picture2

5.In the selection window,  give the output file name and location for shapefile that need to be created.picture3

6.In the autofill settings, preferably select fill with parameter value if you want to save the content of kml file.picture4

7.By default , keep yes in load in QGIS.

8.Once all the kml has been loaded in Input layer, click on run. Close window when batch process complete come.

9.Result will be displayed as followspicture5

Birds in backward

The winter rain invites the birds to enjoy the garden, when all us humans sit comfortably in our bed. This is my first sighting of red billed blue magpie robin in the campus and what a sighting! the blue whistling thrush was hopping in the garden , and both the birds were enjoying their lunch time in dehradun drizzle.

glimpses of periyar tiger reserve

The beautiful Periyar Tiger reserve is located in Kerala. The nearest airport is Kochi which itself is a beautiful place to be in. A short visit to this tiger reserve, yet so many memories for me to carry forward. Although Periyar is famous for elephants but the giants eluded me. Saw them in one of the resort who were catering to the joyride for tourists. Although lucky me got to see wild dog, sambar, gaur, wild boar. The major sightings were of tourists though :p