function varargout = zad_4(varargin)
% ZAD_4 MATLAB code for zad_4.fig
%      ZAD_4, by itself, creates a new ZAD_4 or raises the existing
%      singleton*.
%
%      H = ZAD_4 returns the handle to a new ZAD_4 or the handle to
%      the existing singleton*.
%
%      ZAD_4('CALLBACK',hObject,eventData,handles,...) calls the local
%      function named CALLBACK in ZAD_4.M with the given input arguments.
%
%      ZAD_4('Property','Value',...) creates a new ZAD_4 or raises the
%      existing singleton*.  Starting from the left, property value pairs are
%      applied to the GUI before zad_4_OpeningFcn gets called.  An
%      unrecognized property name or invalid value makes property application
%      stop.  All inputs are passed to zad_4_OpeningFcn via varargin.
%
%      *See GUI Options on GUIDE's Tools menu.  Choose "GUI allows only one
%      instance to run (singleton)".
%
% See also: GUIDE, GUIDATA, GUIHANDLES

% Edit the above text to modify the response to help zad_4

% Last Modified by GUIDE v2.5 30-May-2016 18:15:49

% Begin initialization code - DO NOT EDIT
gui_Singleton = 1;
gui_State = struct('gui_Name',       mfilename, ...
                   'gui_Singleton',  gui_Singleton, ...
                   'gui_OpeningFcn', @zad_4_OpeningFcn, ...
                   'gui_OutputFcn',  @zad_4_OutputFcn, ...
                   'gui_LayoutFcn',  [] , ...
                   'gui_Callback',   []);
if nargin && ischar(varargin{1})
    gui_State.gui_Callback = str2func(varargin{1});
end

if nargout
    [varargout{1:nargout}] = gui_mainfcn(gui_State, varargin{:});
else
    gui_mainfcn(gui_State, varargin{:});
end

% End initialization code - DO NOT EDIT

function zad_4_OpeningFcn(hObject, eventdata, handles, varargin)

handles.output = hObject;

guidata(hObject, handles);

% city Kamennomostskiy
lat = 44.300703;
lon = 40.183990;

terrain = getTerrain(lat,lon);
minHeight = -499;
maxHeight = 3500;

colMat = [
0.0 0.0 0.7
0.0 0.8 0.0
0.0 1.0 0.0
1.0 1.0 0.0
1.0 0.8 0.0
1.0 0.0 0.0
0.7 0.0 0.0
0.4 0.0 0.0 ];

delta = 0.8365;
lat_s = lat - delta;
lon_s = lon - delta;
latPoints = [ceil(lat) floor(lat)];
lonPoints = [floor(lon) ceil(lon)];

lat_diff = 201-(latPoints - lat_s)*100/delta;
lon_diff = (lonPoints - lon_s)*100/delta;

axes(handles.axes1);
imagesc(terrain, [minHeight maxHeight]);
colormap(colMat);
colorbar;

xLabelName='Longitude °';
yLabelName='Latitude °';
xlabel(xLabelName);
ylabel(yLabelName);

set(gca,'XGrid','on','YGrid','on','XTickLabel',lonPoints,'XTick',lon_diff,'YTickLabel',latPoints,'YTick',lat_diff);
hold on;
plot(101,101,'ko');
text(105,101,'Kamennomostskiy','Color','Black');


% --- Outputs from this function are returned to the command line.
function varargout = zad_4_OutputFcn(hObject, eventdata, handles)
% varargout  cell array for returning output args (see VARARGOUT);
% hObject    handle to figure
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

% Get default command line output from handles structure
varargout{1} = handles.output;


function terrain = getTerrain(lat, lon)
pixelsPerDegree = 120;
columns = 4800;

dLAT = 90 - lat;
dLON = 20 + lon;

x = round(dLON * pixelsPerDegree) - 100;
y = round(dLAT * pixelsPerDegree) - 100;

f = fopen('E020N90.DEM', 'r');
terrain = zeros(201, 201, 'double');

for i = 1 : 201
   fseek(f, ((y + i) * columns + x ) * 2, 'bof');
   terrain(i, :) = fread(f, 201, 'int16', 0, 'b');
end

fclose(f);