- Open by:
- To download data
- Zoom to your area of interest;
- Click the Download tool on the right side of the title bar;
- Choose a reference area polygon; it is probably easiest to just
download the entire screen.
- Select available data products. The most useful will be:
- Land cover--but this does not have the 1992 data,
which you must get from MLRC.
- Elevation Products (3DEP): this is
3DEP/NED in 1", 1/3"
available nationwide; and 1/9", and the 1 m DEM
available in some locations.
- Elevation Source Data (3DEP): LAS files. These
- Names--Geographic Names Information System (GNIS, or
- Less useful
resolution imagery. WMS Maps
may be a viable alternative.
- Imagery--1 foot (HRO) .This imagery may have the choice of multiple dates, some of
which will include 4 bands with IR for vegetation
- Imagery--1 meter (NAIP)
- NHD: you probably want the shapefiles for Dynamic
Extract and Dynamic extract with flow table.
- Select format. If possible you want Geotiff or
Shapefile as the best formats for use in MICRODEM. In
particular avoid the Geodatabase, which is a
proprietary ESRI format for Arc. Some other formats will require
that that you have GDAL
downloaded and correctly set up.
For the elevation data there are three formats, all of which work
with varying challenges. All will be zipped initially.
- GridFloat will be the best option; select the .FLT file.
You also need the .HDR file, and must keep the two files together.
- IMG is the next best choice; you select the IMG file and
GDAL converts to a Geotiff
which will open.
- ArcGrid is the trickiest choice; you must use
GDAL and then pick the
correct "w001001.adf" file which will be in directory called
something like "grdn39w077_13".
Zoom map to show your area.
Pick the option for "Current extent" on the top of the mpa.
For download, you can:
- Download file by file, the easiest choice if you want just a few
- You must pick
the data you want and add to your cart (you use +All instead of checking
each individually). Then view cart. You can download all files
Download each layer individually.
You can try to use the
BDA (Bulk Download Application). It may have challenges, some of which
might be institutional security measures.
National Map Alternatives
The table below shows alternatives to the National Map if the site is down or unresponsive. These might
also be faster and easier to use. Most options now require you to
get pre-packaged tiles, instead of packaging the region on demand that was
possible with the Seamless Server model.
Last revision 11/2/2018