i

X

Intention

The vision of Maps-For-Free is to offer free worldwide relief maps and other layers which tin can easily exist integrated into existing map projects.

MFF-maps are released under Creative Commons CC0. You are gratis to adapt and use the relief maps and relief layer for commercial purposes without attributing the original writer or source. Although not required, a link to maps-for-free.com is appreciated.

SRTM

SRTM (Shuttle Radar Topography Mission) was developed to collect three-dimensional measurements of the Globe'southward surface to generate a near-global digital summit model (DEM). The mission was a cooperative projection between the National Aeronautics and Infinite Administration (NASA), the National Geospatial-Intelligence Bureau (NGA) of the U.South. Department of Defense (DoD), and the German and Italian space agencies.

SRTM flew on board the Space Shuttle Endeavour in Feb 2000 and used an interferometric radar organization to map the topography of Globe's surface. Endeavour was launched in an orbit with an inclination of 57 degrees which allowed to map all of the Earth's landmass that lies between 60 degrees North and 56 degrees South.

SRTM information was processed into geographic tiles, each of which represents 1 by one degree of latitude and longitude. A caste of breadth measures 111 kilometers Due north South, a degree of longitude measures 111 kilometers East West or less, decreasing away from the equator. Each tile of this dataset contains 1201x1201 samples which is equipollent to a 90 thousand filigree resolution at equator. All tiles together represent an prototype sized 432000 10 139200 pixel.

For technical reasons information are available between 60 degrees North and 56 degrees South latitud only. The relative horizontal accuracy is about ± fifteen m, the relative vertical accuracy nearly ± 6 1000. The original data came with data voids indicating bereft contrast in the radar data. These data voids tend to occur over water bodies (lakes, rivers, coasts, etc.), areas with snowfall cover and in mountainous regions.

The original SRTM data are bachelor from USGS.

GTOPO30

GTOPO30 is some other free geographic dataset with a resolution of 43200 x 21600 pixel used to embrace regions where SRTM data are not bachelor. Streaky regions denote areas where data voids were extrapolated or where SRTM data were replaced past the lower resolution GTOPO30 data.

The relief maps are elevation maps, i.e. the coloring does not reflect the natural colors of scenic objects. Because one color is used for each ground level, some rivers and other objects may appear in unnatural colors. Lowland areas containing only few elevation information announced most likely single-colored.

In some cases the SRTM or GTOPO30 dataset failed to include small islands, and in other cases the islands are slightly mispositioned.

The GTOPO data are also available from USGS.

VMap0

VMap0 provides worldwide coverage of geo-spatial data and is equivalent to a calibration of ane:meg. The data are structured post-obit the Vector Product Format (VPF) and tin be downloaded from GIS-Lab. Near of the MFF-layers are based on one of the thematic data vmap0 layer.

Hans Braxmeier, Donaustraße 13, 89231 Neu-Ulm, Frg, [email protected], 01-01-2017

DOWNLOAD HERE

Posted by: connierearach.blogspot.com