Download a grid

Download a grid in Eduard

To download a grid do one of the following:

• Choose File > Download Grid (at the top of your screen).

• Click on the “Download a grid” button at the center of a new document.

• Click on the Download button in the toolbar.

Specify the download area

Zoom in and out: Click the zoom buttons (– and +) in the lower-right corner of the map, use the scroll wheel of your mouse, use a pinch gesture on your trackpad, or double click to zoom in and option-double click to zoom out.
Move the blue knobs to adjust the size of the download area.
Move the background map to adjust the download area.
Click the map icon at the bottom of the window to change the map type.

Polar areas are not included by some elevation models. Polar areas without elevation data are indicated in red on the map.

Select the elevation model

ALOS 30 m: The ALOS Digital Surface Model with a cell size of one arc second or approximately 30 meter.
MERIT DEM 90 m: An error-removed version of the ALOS and SRTM elevation models with “geographic” coordinates and a cell size of 3 arc seconds or approximately 90 meter.
NASADEM 30 m: An improved version of the SRTM elevation model with a cell size of 1 arc second or approximately 30 meter.
SRTM 30 or 90 m : The NASA SRTM elevation model with a cell size of 1 or 3 arc seconds, or approximately 30 or 90 meter.
Mapzen Terrain Tiles: Elevation data at various resolutions compiled from various sources by Mapzen.

For more information about the elevation models, click on the links in the bottom-left corner of the download window.

Select the projection

ALOS, MERIT DEM NASADEM and SRTM elevation models are distributed in a “geographic” coordinates system using latitude and longitude coordinates. Mapzen Terrain Tiles use the web Mercator projection. Choose either “Mercator” or “Geographic”. Eduard transforms the downloaded grid when necessary with cubic interpolation.

Download and save the grid file

Click Download to request a grid from the OpenTopography server or an Amazon AWS server for Mapzen terrain tiles. Then save the grid in a GeoTIFF file.

OpenTopography API key

ALOS, NASADEM and SRTM elevation models are provided by OpenTopography and require a free API key to download. Create an account and request an API key at OpenTopography.org . When you attempt to download an elevation model from OpenTopography and you have not provided an API key, then the dialog below will guide you through the process of requesting and entering an API key.

The OpenTopography API key can also be changed with Eduard > Settings (from the Eduard menu at the top-left of your screen). This is useful if you entered a wrong API key or want to change your key.

MERIT DEM user name and password

A user name and a password are required to download MERIT DEM data. Request these at http://hydro.iis.u-tokyo.ac.jp/~yamadai/MERIT_DEM/ . When you attempt to download MERIT DEM data and you have not provided a user name and a password, then the dialog below will guide you through the process .

The MERIT DEM user name and password can also be changed with Eduard > Settings (from the Eduard menu at the top-left of your screen).

Mapzen downloads

Mapzen terrain data includes values below the mean sea level. Deep values can result in poor shaded relief. Eduard can replace all negative values with a zero value. To do so, select Eduard > Preferences (from the Eduard menu at the top-left of your screen), and activate Limit Mapzen Downloads to Mean Sea Level.

Download cache

Eduard caches downloaded MERIT DEM data and Mapzen terrain tiles. To adjust the size of the cache and to clear the cache, select Eduard > Settings (from the Eduard menu at the top-left of your screen) and click Download. The cached data is stored on the main drive and can be removed with the Clear Cache button. The cache never grows beyond the maximum size that you specify in the Settings dialog.