OrientDB geolocation -


i´m using orientdb nosql database, , dont know how query in geolocation exactly. i´ve read specific documentation:

orientdb functions

but not understand significance of values.

the distance function:

distance() - computes distance between 2 points in globe using haversine algorithm. coordinates must degrees

example:

where distance(x, y,52.20472, 0.14056) <= 30

two questions:

  1. what x, y, , 30 values?
  2. are values (52.20472, 0.14056) latitude , longitude?

thanks!

distance(x, y,52.20472, 0.14056) <= 30

x , y longitude , latitude (variables) respectively of record/position calculating distance fixed coordinates 52.20472, 0.14056.

consider example:

select distance(longitude, latitude, 52.20472, 0.14056) <= 30 distance places order distance

this query loop through records in places class/cluster , each record injects longitude , latitude of record , calculate it's distance fixed position (52.20472, 0.14056) , return places within 30m.

where

places class/cluster contains records of places longitude longitude field of current record latitude latitude field of current record distance alias field name


Comments

Post a Comment

Popular posts from this blog

Why can rails not find a route created by a helper? -

i created member route in rails 4: resources :line_items post 'decrement', on: :member end and gave matching method in line_items controller: def decrement @cart = current_cart @line_item = @cart.line_items.find_by_id(params[:id]) @line_item.decrement_quantity respond_to |format| if @line_item.save format.html { redirect_to shop_path, notice: 'line item updated.' } format.js {@current_item = @line_item} format.json { head :ok } else format.html { render action: "edit" } format.js {@current_item = @line_item} format.json { render json: @line_item.errors, status: :unprocessable_entity } end end end but when try make button: <%= button_to 'x', decrement_line_item_path(item) %> i error: no route matches [post] "/carts/25" what gives? your error message is: no route matches [post] "/carts/25" but expectin...
Read more

javascript - jquery or ashx not working -

i using ajax file upload control. it creating html: <form action="/pages/handlers/asyncfileuploadhandler.ashx" method="post" enctype="multipart/form-data" target="ajaxuploader-iframe-1397144545"> <input type="hidden" name="type" value="mindvoice"> <input type="file" id="imagefile" style="display: block; width: 80%; margin-right: auto; margin-left: auto;"> </form> and target is: <iframe width="0" height="0" style="display:none;" name="ajaxuploader-iframe-1397144545" id="ajaxuploader-iframe-1397144545"></iframe> the form submitted using .submit() . my ashx handler: <%@ webhandler language="c#" class="asyncfileuploadhandler" %> using system; using system.web; using nettpals.core; public class asyncfileuploadhandler : ihttphandler { public void processre...
Read more

opencv - DataType<cv::detail::deriv_type>::depth what is it used for -

i wondering why line used in lucas kanade tracker in opencv: datatype<cv::detail::deriv_type>::depth can explain me? in opencv, depth of mat refers type of data contained in mat 's data buffer. represented integer values correspond given data type. these integers commonly abstracted appropriate macro definition (e.g. uchar data represented macro cv_8u ). cv::datatype type-traits class provides method obtain corresponding integer value without having memorize macro means data type. there few cases user code needs use datatype::depth . more common datatype::type . a simple example shows 1 possible use of datatype::depth : cv::mat uchar_data = cv::mat::ones(3, 3, cv_8uc1); cv::mat float_data; uchar_data.convertto(float_data, cv::datatype<float>::depth); // ^^ equivalently replaced // cv_32f macro float_data.at<float>(0,1) += 0.5f; std::cout << float_data << std::endl;...
Read more