Very new to QGIS. I'm using it to analyse agricultural field microplots for research.
I need to give each field plot its own object which I've done so by using the "create grid" tool. But I need to assign a column and row number to each object in the attribute table to make it easier to sort the data. This should start in the bottom left (1:1) and ascend in row for objects above (2:1) and ascend in column for objects to the right (1:2).
I've orientated the grid to start in the bottom left and learned that by using #row_number, I can re-number the objects from 1 to the total number of objects. But I need to add column number and row number to the attribute table.
Is there a simple way of doing this?
I think the most accessible option here is using the field calculator to add two integer columns to the attribute table. For a rectilinear grid with cells_y cells in the y direction (24 in this case) the expressions are something like
floor(("id" - 1) / cells_y) + 1
where id is the attribute table column with the cell number (set automatically by Vector -> Research Tools -> Create grid or, in the OP's case, to #rownumber).
For the y index it's
cells_y + 1 - if(("id" % cells_y) = 0, cells_y, "id" % cells_y)
This is for the ones based indexing asked for here; remove the + 1 bits for zero-based. Similarly, subtracting (as is done with y here) or not subtracting (x here) the modulus part flips the directions in which the cells are numbered. This approach can also be used in PyQGIS.
There's a few grid plugins for QGIS and several similar StackOverflow questions (like this one) which may also be of interest.
Related
On one sheet, I have account code and in the cell next to it, I need to look up the account code on the next sheet to average the cost excluding those cells that are zero in col. b from the average calculation.
The answer for London should be: £496.33 but having tried various sumifs / countifs I cannot get it to work.
You probably need COUNTIFS which -- similar to the SUMIFS you are already using -- allows to define multiple critera and ranges.
So, if the column R contains the values, you want to build the average upon, and the column H in the respective row must equal $B$28 to be included in the sum, the respective COUNTIFS looks as follows
=SUMIFS('ESL Info'!$R:$R,'ESL Info'!H:H,$B$28)/COUNTIFS('ESL Info'!$H:$H,$B$28, 'ESL Info'!$R:$R, "<>0")
ie additionally to the value in the H-column to equal B28 it also requires the value R-column (ie the actual number you are summing up) to be different from 0
You could also add the same criteria 'ESL Info'!$R:$R, "<>0" to your SUMIFS, but that isn't necessary, because a 0 doesn't provide anything to you sum, thus it doesn't matter if it's included in the sum or not ...
And depending on the Excel version you are using, you may even have the AVERAGEIFS function available, which does exactly what you want
=AVERAGEIFS('ESL Info'!$R:$R,'ESL Info'!$H:$H;$B$28,'ESL Info'!$R:$R,"<>0")
Simplified example: column of 'measure' data is binary 0's and 1's. The sum of the column (all the 1's summed) is 3948. The length of the column is 4567. 3948 is 86% of 4567. How do I create a bar chart showing this percentage. All I can get is a bar adding up to 100%.
I've tried absolutely everything in the percentage of dropdown, calculated fields, online tutorials, etc.
Two approaches:
Right click on your measure field on whichever shelf you placed it. Choose Quick Table Calc -> Percentage of Total. Experiment with different settings for "Compute Using" and read about addressing and partitioning of table calculations to learn how to specify percent of "what".
Or create a calculated field specific to your problem defined as below:
sum(int([my measure field] = 1)) / count(1)
Be sure to set the default number format for your calculated field to a percentage, by right clicking on it in the data pane (left margin) and revising the default properties
Note, the second calculation works because the INT() function converts True to 1 and False to 0, which is useful in several contexts.
You can go about this using the following method
Add 'measure' to Columns and make it a Discrete Dimension
Add SUM(Number of Records) to Rows. This should give you the bar chart you need.
This would help achieve what you are looking to do. For more customization and a better look for the graph you are looking to build in Tableau.
Add 'measure' to the colour legend and make it a Discrete Dimension.
Add SUM(Number of Records) as a Label and do a '% of Total' quick table calculation.
I'm tasked with creating a GUI solution using guide to the travelling salesman problem. It's to have a drop down menu allowing the user to select from 10,20,30...100 cities, then a button to generate a map from the cities and the unoptimized route. Another button is to optimize the solution using a simple method. I've built the code that generates the initial map onto a plot, using the drop down menu selection of cities.
My problem is the optimization. Initially, a random matrix with 2 columns and however many cities selected for rows is created, representing x, and y co-ordinates on a map. The method we are to use is split into 2 procedures, procedure 1 takes the start point, entry 1 of the matrix, and 2 other random vectors, then it's meant to take a random city, compute the distance betweeen it and all the other cities in the tour vector (the one that starts at 3 x+y co-ords), then insert itself next to the city with the shortest route. repeat the procedure until all cities are inserted into the matrix in a semi-optimized state. Procedure 2 takes the full tour matrix, and then attempts to look at each city in it and move it to the position with the least travelled distance between the two neighbouring cities.
The problem I'm seeing is that, whilst deleting a row of a matrix is an easy option, inserting and moving rows is something I've never encountered before. Are there any functions that do such a thing in the standard matlab library?
If I read the question correctly, you are just looking for basic matrix manipulation.
Suppose you have a matrix X and want to insert a row after the second row:
X = reshape(1:8,4,[])
myRow = [0 0];
X = [X(1:2,:); myRow; X(3:end,:)]
If you want to move a row:
1. Assign it to myRow
2. Delete it
3. Insert the new row with the code above
If you want to swap rows, you can take a more direct route, suppose you want to swap row 2 and 4:
X = reshape(1:8,4,[])
X([2 4],:) = X([4 2],:)
If you simply want to update a row, it gets even easier. Suppose you want to update the second row:
X = reshape(1:8,4,[])
myRow = [0 0];
X(2,:) = myRow
I have a challenge in Oracle Apex - I would to sum multiple columns to give 3 extra rows namely points, Score, %score. There are more columns but I'm only choosing a few for now.
Below is an example structure of my data:
Town | Sector | Outside| Inside |Available|Price
Roy-----Formal----0----------0----------1------0
Kobus --Formal----0 ---------0--------- 1------0
Wika ---Formal----0----------0--------- 1------0
Mevo----Formal----1----------1----------1------0
Hoch----Formal----1----------1----------1------1
Points------------2----------2----------5------1
Score------------10---------10---------10------10
%score-----------20---------20---------50------10
Each column has a constant weighting (which serves as a factor and it can change depending on the areas). In this case, the weighting for the areas are in the first row of the sector Formal:
Sector |Outside| Inside |Available|Price
Formal----1----------1 ----------1-----1
Informal--1----------0 ----------2-----1
I tried using the aggregate sum function in apex but it wont work because I need the factor in the other table. This is where my challenge began.
To compute the rows below the report
points = sum per column * weighting factor per column
Score = sum of no of shops visited (in this case its 5) * weighting factor per column
% score = points/Score * 100
The report should display as described above. With the new computed rows below.
I kindly ask anyone to assist me with this challenge as I have tried searching for solutions but haven't come across any.
Thanks a lot for your support in advance!!
i'm trying to draw a Graph with a user-friendly timeline having every day/week (to be decided by time range) as a label at x-axis. However, the datasource values are given on another basis - there might be 10 entries one day and the eleventh comes in a month.
See the photoshop image:
With the latest Core Plot drop I cannot find a way to do it, need your help.
Regards,
user792677.
The scatter plot asks the datasource for x-y pairs of data. There is no requirement that either value follow some sort of sequence or regular pattern. Other plot types work similarly, although the names and number of data fields can vary.
In your example, return 4 from the -numberOfRecordsForPlot: method. Return the following values from the -numberForPlot:field:recordIndex: method. The table assumes your y-values are calculated by a function f(x), but they can of course come from any source. Use the field parameter to determine whether the plot is asking for the x- or y- value.
Index X-Value Y-Value
0 1 f(1)
1 3 f(3)
2 9 f(9)
3 10 f(10)