Developers Club geek daily blog

How to draw curve diagrams in XKCD style

1 year, 4 months ago
Recently I published article on Habré about the guitar tuner, and the animated diagrams which I used for an illustration of sound waves, including technology of creation of such diagrams interested many. Therefore in this article I will share the approach and a bibliotechka on Node.js which will help to build similar diagrams.



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We configure a linking of Apache Zeppelin + Oracle

1 year, 5 months ago
Long ago I look for the convenient tool for execution of ad hoc SQL queries in Oracle DB, with a possibility of fast creation of different types of diagrams on data retrieveds. Everything that can facilitate operational creation of reports, as they say "on the fly". Quite recently came across here such tool as Apache Zeppelin. The short overview of opportunities on the website and a demo video showed in documentation that it is piece rather interesting and it makes sense to investigate more densely it and to configure access from Apache Zeppelin to Oracle DBMS.


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Approach to implementation of the big formatted reports in SAP BW

1 year, 5 months ago
On projects of implementation of the reporting with use of the data storage of SAP BW many architects and consultants should solve problems of preparation of the big formatted reports: various sheets, statements, etc. Such reports are usually characterized:

  • Requirements to formatting, non-standard concerning tools of SAP;
  • The fixed number of columns;
  • Significant amount of columns and lines (respectively, tens and tens of thousands and more);
  • Requirement of existence of Excel-representation;
  • Requirement to runtime no more than several minutes

Unfortunately, quite often it is necessary to observe a situation when architects of BW projects select approach of implementation of such reports, standard for BW. Briefly the essence of this approach is stated below.

The consultant creates the workbook of BW-BEx which contains one or several BW - BEx - reports. Reports are unloaded on single sheets of this book which usually hide from users. Visible leave only one leaf of the book containing a target form of the report with necessary formatting.

Work of the user with such report looks as follows:

  • depending on the used SAP BW Excel-tool, the user starts BW-BEx Analyzer or SBOP Analysis for Office, is connected to the SAP BW server, selects the workbook from a role and starts it on execution.
    In several seconds (sometimes – ten seconds) the selection screen appears.
    On the screen the user selects values of parameters. For example, year-month, balance sheet unit, group of material, etc. Then clicks "to execute".
  • Now queue came "to work" for SAP BW: in total BW - BEx - reports of the workbook are executed consistently, the report behind the report, transferring the data to work sheets of Excel.
  • After obtaining in Excel of data of each report the VBA macro is started. Logic of work of a macro such is that it does nothing until data of all reports are obtained on Excel-sheets.
  • When data of the last report arrived on an Excel-leaf, the VBA macro performs the main work on preparation of formatting of the report.
  • When the VBA macro completed work, the user can see result of the report in the Excel.

Standard approach has a number of benefits: it is simple in implementation and it most of specialists in the market well own. But certain restrictions do not allow to implement big reports effectively. And inefficient implementation turns out (if at all it turns out) very inconvenient in work that negatively affects the relation of users to the project of implementation in general and to SAP BW in particular. The main restriction – the maximum quantity of cells (the number of lines increased by number of columns) in the report. If their number comes nearer to empirical 750000, then probability of failure because of memory contention of nearly 100%. I.e. the report from only 18 columns and a little more than 40000 lines already gets under this restriction. And limits Excel have much more.

What is only not thought out by consultants that, remaining within standard approach, qualitatively to make the big report. But almost always nothing is impossible. "Almost" means compromises, eases in requirements. Business users or agree to use more limiting filters and the report returns less data, or to wait for execution longer, or to manually reduce several fragments of the report in one.

After all not to speak to the client "is not present, we cannot implement it at such requirements", it is necessary to draw for a start the correct conclusions from obvious: each tool is intended for the task.

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The analysis combined by ABC and XYZ in the Retail

1 year, 5 months ago
Once long ago the owner of shop, it is seller, could remember all goods of the range easily. To tell about features of everyone, history as far as the goods are effective, knew precisely as it is on sale when to order still …

With development of retail traffic control of goods demands other approaches. Systems of accounting and analytics of sales, managements of the range supplement experience of employees of shop or distribution network.

Serious solutions, for example, on removal of goods from the range, are accepted not so simply. Both the category manager, and the managing director of shop needs justifications for such actions.

Therefore one type of the analysis insufficiently. Apply combination of several types (in a different way, the cross-analysis).

In article we on the example of commodity group of "Confectionery" will consider basic approaches to the organization of the cross-analysis. And still we learn who is guilty that Rafaello — goods with unstable sales.

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Visualization of static and dynamic networks on R, part 6

1 year, 5 months ago
In the first part:
  • visualization of networks: what for? how?
  • visualization parameters
  • best practices — esthetics and productivity
  • data formats and preparation
  • the description of data sets which are used in examples
  • the beginning of work with igraph

In the second part: colors and fonts in diagrams R.

In the third part: parameters of graphs, tops and edges.

In the fourth part: placements of network.

In the fifth part: emphasis of properties of network, tops, edges, ways.

In this part: interactive visualization of networks, other ways of representation of network.

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Thematic cartography: general questions

1 year, 5 months ago


I want to share with you transfer of the guide to thematic cartography from children from axismaps.

I recommend for reading to information designers, journalists (data), analysts, the beginning cartographers, and also everything who wants to learn to read thematic maps and to distinguish the good card from bad, misleading the reader. I invite all become interested under kat.

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We look for stability in retail, the XYZ analysis of the range

1 year, 5 months ago
The XYZ analysis — one of forms of the analysis of the commodity range of shop, network or separate commodity group in retail.



The XYZ analysis defines stability of sales of goods for certain period. It is useful to management of the range and deliveries of goods, the organization of work with suppliers. Results allow to separate goods on categories and to select for them place in warehouse, stock rate and the organization of delivery.

As the separate method of the analysis in retail of XYZ is used not so often, more often he can be met as combined with ABC analysis.
But, anyway, as the method for decision-making on management of the range of commodity group or shop can bring undoubted benefit.

Let's begin with consideration of its features and opportunities of application.

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Visualization of static and dynamic networks on R, part 5

1 year, 6 months ago
In the first part:
  • visualization of networks: what for? how?
  • visualization parameters
  • best practices — esthetics and productivity
  • data formats and preparation
  • the description of data sets which are used in examples
  • the beginning of work with igraph

In the second part: colors and fonts in diagrams R.

In the third part: parameters of graphs, tops and edges.

In the fourth part: placements of network.

In this part: emphasis of properties of network, tops, edges, ways.

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The redirection of data from COM port in web. Completion

1 year, 6 months ago
Recently I have published the article "Perenapravleniye of Data from COM Port in Web" in which has described prototype of the system broadcasting lines from serial port of the computer in the web browser. I have specified the directions in which it is necessary to finish prototype in that article to approach it to prodakshen-stage:
— any design of the web page
— in each timepoint data will be obtained only by one web client
— very limited set of browsers by means of which it is possible to get access. For example, does not work neither in Internet Explorer 8, nor in the browser from Android 2.3.5
— the python installation is required

After a while I have decided not to leave it in such look and to finish. Under cat result of completion and the description of how I have eliminated all listed defects.

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Design of the card: as well as why

1 year, 6 months ago
It is possible to find enough materials on creation of styles of cards in network (and on Habré including), but generally they show technical aspect of creation of style in tilemill/mapbox studio. And here with the theory of business are much worse, generally write about any separate aspects of design, and not always explain that why it is necessary to do so, but not differently. In this article I will try to correct this situation and to share experience with the beginning kartostroitel.


I ask all interested under kat.

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