How to merge adjacent polygons automatically - attributes

I have a vector file which contains adjacent polygons and I want to merge or 'dissolve' it into one based only on their adjacency. Not having a common attribute field does not allow use of 'dissolve' feature. I do not want to dissolve non-adjacent polygons because later I want to filter features such as selection of features with > 100 sq. km and such. I have used QGIS's Join Attributes by nearest feature with a maximum distance of 0 to find feature adjacency.
Please follow the link below to download the polygon shapefile. This is just part of a large vector file. I want to do it automatically, manually doing it is my last resort.
https://drive.google.com/drive/folders/1G_irrjmzq19LljMtELT-B0tpX9gHfqD7?usp=sharing

Related

Excel - How to find intersection point of two lines on a graph

I have a graph which has two lines.
The graph is generated from "random" data. I.e. not based on a formula or pattern. But there is always a point where the two lines intersect.
I'm trying to provide exact point (on x and y axis) where the lines cross.
Ive tried using slope/intercept formulas
And what if analysis.
However these methods only seem to work if the data is based on a formula or pattern.
I can sort the data and find the point where they are at their closest then take an average using data around that point to get an approximate match.
However is there any way to do this more accurately, or does the nature of my data(random data points) make this not possible using formulas/equations

How to highlight specific data points in a scatterplot (Excel) based on certain conditions?

Suppose I have a data with two sets of xy coordinates, one pair for the customer side and one pair for the vendor side (so in total, there should be four columns, two x's and two y's). We can call Xc for customer and Xv for vendor and vice versa for Y. I know how to make a plot in excel and overlay the two pairs of coordinates, but I am stuck on how to present such plot with specific data points highlighted with a different symbol/color based on conditional statements. For example, if any data points in Xc or Yv have coordinates outside of a specific range (think of them as outliers), I would like to flag such points on the scatterplot. I know one way is to filter out the points first and create it as a separate series then plot, but wonder if there is a more streamlined procedure in doing so as I need to make a template for future references. Any help would be greatly appreciated.

How to calculate the percentage of total area of features having specific attributes' values with Qgis?

I'm working in QGis with different layers covering the same geographical extent. Taking the intersection of those layers, I generated a new one whose attribute table contains all the attributes from the different layers. I would then like to know if there is a tool in Qgis that would allow me to generate the percentage areas covered by features corresponding to specific attributes' value. Would it be possible to compare for example the areas in percentages of the features caracterised by value A and Value B of Attibute 1 and 2 with the one of the features caracterised by value C and D of the same attributes?
Thank you very much for your help.
Regards,

Paraview-Creation of 3D body from points

I want ask how to create an object (coherent body), if I have 3 excel files (approximately 1mil. Rows each) with X Y Z coordinate. After importing to Paraview I have ‘object’ as in figure below, it consist of 25 ‘planes’ which consist of points from excel files. I need to make from this planes one object with coherent body, basically wrap this planes with something. Is it possible with use of some filters in Paraview or do I need some programmable filter ? I have tried few things but the result was not satisfying.
Apply Table to Points filter to generate a point set and then apply the Delaunay 3D filter to get a surface from those points.

How to produce the data points for a circle in Excel using ROW INDIRECT

The page linked to here has been a great help to me. The method of using the named function (=(ROW(INDIRECT("1:361"))-1)*PI()/180) to produce the circle data points is very slick compared to my original method that was to calculate them individually, writing them in to rows.
My data set includes some 50k rows of data, each one defining a circle. The set is divided into 50 groups and I need to plot one circle from each group as selected via a scroll bar controlling a LOOKUP routine.
Please can someone suggest how I might modify the function (=(ROW(INDIRECT("1:361"))-1)*PI()/180) to reduce the number of data points it produces? I want to reduce the computing load and also, it's not practical to display & format data markers with such high data density. My existing circles are produced with just 18 coordinate pairs and are satisfactorily rounded.
Thanks in advance. Steve.
This would give you 19 data points, 0 and 360 as the start/end points with another every 20%
=(ROW(INDIRECT("1:19"))-1)*PI()/9

Resources