creating a shapefile or geojson file

I have geopoints of a boat track and other vectors like dateTime vector, CourseOverGround(degree),Speed over Ground(in knots) . I am not able to write the shape file . Only geopoints are written. Please help.

[KSSV]

What error you are getting? Show us your code.

[Urmila Datta]

Shape=geopoint(latitude,longitude);
CourseOverGround=[0 ;beta]; % beta a vector angles
SpeedOverGround=[0 ;sog_knt];% sog_knt a vector of speed values
dateTime=timeInterp; % datetime vector 

dbfspec=makedbfspec(Shape);
dbfspec=struct('dateTime',timeInterp,'sog',SpeedOverGround,'cog',CourseOverGround);
shapewrite(Shape,'test.shp','DbfSpec',dbfspec);

Answer 1

[Siraj]

Hi!

It is my understanding that you have a boat track dataset consisting of geopoints representing the boat's locations at different times, along with other attributes such as timestamp, “CourseOverGround (in degrees)”, and “Speed over Ground (in knots)” and want to store data in a shape file but are facing some issues.

To address this, one alternative approach can be to use the "geopoint" function to create a container object that holds geographic point coordinates and attributes. By utilizing the dot notation, attributes such as “dateTime”, “CourseOverGround”, and “SpeedOverGround” can be dynamically added to the "geopoint" object. Subsequently, the enhanced object can be written to a shapefile using the "shapewrite" function. Refer to the following code for a clearer understanding.

% Define the range for latitudes and longitudes
latRange = [8, 37]; % Latitude range 
lonRange = [68, 97]; % Longitude range f

% Generate vectors of latitudes and longitudes
latitudes = linspace(latRange(1), latRange(2), 10);
longitudes = linspace(lonRange(1), lonRange(2), 10);

% Generating CourseOverGround
numPoints = 10; % Number of points, same as the length of latitudes and longitudes
minCOG = 0; % Minimum value for CourseOverGround
maxCOG = 360; % Maximum value for CourseOverGround

% Generate random values for CourseOverGround
CourseOverGround = rand(1, numPoints) * (maxCOG - minCOG) + minCOG;

% Generating SpeedOverGround 
numPoints = 10; % Number of points, same as the length of latitudes and longitudes
minSOG = 0; % Minimum value for SpeedOverGround
maxSOG = 10; % Maximum value for SpeedOverGround

% Generate random values for SpeedOverGround
SpeedOverGround = rand(1, numPoints) * (maxSOG - minSOG) + minSOG;

shape = geopoint(latitudes, longitudes);
shape.CourseOverGround = CourseOverGround;
shape.SpeedOverGround = SpeedOverGround;

dbfspec = makedbfspec(shape);

shapewrite(shape, "test.shp", 'DbfSpec',dbfspec)

S = shaperead("test.shp");
T = struct2table(S)

T = 10×5 table
    Geometry       X         Y       CourseOverG    SpeedOverGr
    _________    ______    ______    ___________    ___________

    {'Point'}        68         8       9.538          6.615   
    {'Point'}    71.222    11.222      182.54         1.8426   
    {'Point'}    74.444    14.444      338.76         1.5514   
    {'Point'}    77.667    17.667      312.84         9.3558   
    {'Point'}    80.889    20.889      292.82         4.1901   
    {'Point'}    84.111    24.111      311.94         5.4456   
    {'Point'}    87.333    27.333      33.675         4.2153   
    {'Point'}    90.556    30.556      100.61         5.0957   
    {'Point'}    93.778    33.778       193.2         3.1128   
    {'Point'}        97        37      242.11         1.8382   

Refer to the following links for more information about the "geopoint" and "shapewrite" functions.

https://www.mathworks.com/help/map/ref/geopoint.html

https://www.mathworks.com/help/map/ref/shapewrite.html

Hope this helps.