[SOLVED] What means "Polygons" in .landscape file xml?

[sergio.izquierdo]

Hi, 

I'm trying to make a program for .landscape file generation from .dem files folder. It loops each raster file and extracts information through gdal library.

I would like to know what means "polygons" tag located on each elevation layer:

<Layers>
        <Elevation>
            <heightmap00_00>
                <path>D:/_development_/unigine_projects_2.6/Complex3-Demo/src_design/cartagena_heightmap/heightmap00_00.dem</path>
                <mtime>1523511703534</mtime>
                <raster_count>1</raster_count>
                <raster_size_x>1025</raster_size_x>
                <raster_size_y>1023</raster_size_y>
                <density>4.9964693850869644</density>
                <raster_scale>1</raster_scale>
                <no_data_value>-32767</no_data_value>
                <offset>0</offset>
                <geotransform>-1.1683891806015976 5.6609166666666667e-05 0 37.554680385008979 0 -4.5050555555555556e-05</geotransform>
                <polygons>
                    <polygon size="22">
                        <latitudes>37.554680385008979 37.554680385008979 37.554680385008979 37.554680385008979 37.554680385008979 37.554680385008979 37.545490071675644 37.536299758342309 37.527109445008975 37.517919131675647 37.508728818342313 37.5086387172312 37.5086387172312 37.5086387172312 37.5086387172312 37.5086387172312 37.5086387172312 37.517829030564535 37.527019343897869 37.536209657231197 37.545399970564532 37.554590283897866</latitudes>
                        <longitudes>-1.1683891806015976 -1.1567843014349306 -1.1451794222682643 -1.1335745431015976 -1.1219696639349308 -1.110421393934931 -1.110421393934931 -1.110421393934931 -1.110421393934931 -1.110421393934931 -1.110421393934931 -1.110421393934931 -1.1220262731015975 -1.1336311522682643 -1.1452360314349308 -1.1568409106015973 -1.1683891806015976 -1.1683891806015976 -1.1683891806015976 -1.1683891806015976 -1.1683891806015976 -1.1683891806015976</longitudes>
                    </polygon>
                </polygons>
                <tl_border>37.554680385008979 -1.1683891806015976</tl_border>
                <br_border>37.5086387172312 -1.110421393934931</br_border>
                <description><![CDATA[USGSDEM]]></description>
                <projection><![CDATA[GEOGCS["WGS 84",DATUM["WGS_1984",SPHEROID["WGS 84",6378137,298.257223563,AUTHORITY["EPSG","7030"]],AUTHORITY["EPSG","6326"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4326"]]]]></projection>
                <scale>1</scale>
            </heightmap00_00>

...........

 

Thank you very much

 

 

 

[silent]

Hi Sergio,

That's coordinates of the source boundaries (LAT / LON) for preview generation. 

[sergio.izquierdo]

Ok, so, if my source raster files are projected in EPSG 25830, does it should be in Lat Lon Epsg:4326? What means "preview generation"? If is it a boundary...why polygon size is 22? Please, can you explain it more detailed? 

Thank you very much

[silent]

Size is just a number of elements in longitude and latitude arrays. These coordinates are used for preview generation in Landscape Tool UI and they are basically represent bounds of the source data (heights in your case). Bounds are non-rectangular due to earth curvature, so there are 22 points instead of just couple of them :)

[sergio.izquierdo]

Perfect! thank you very much!