- Select available data products. The most useful will be:
- Elevation Source Data (3DEP): LAS files. These are large
- Names--Geographic Names Information System (GNIS, or gazetteer)
- Less useful
- High
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 analysis.
- 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.
Find products.
For download, you can:
- Download file by file, the easiest choice if you want just a few file.
- 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
together.
Download each layer individually.
- From the results of the search or the cart, export URLs to text
- Use Batch Download on Data Manipulation form if you get the TEXT file.