The USDA Geospatial Data Gateway can be used to download pre-processed collarless topographic maps in MrSid format. These will be compressed county mosaics. Quality varies from county to county, and these products may be of slightly poorer quality (resolution) than the USGS GeoPDF files. However, this method provides a greatly simplified workflow and a means for users to quickly and easily obtain collarless topographic maps of their area of interest without the need of a Global Mapper license.
To download these pre-processed topographic maps, please follow these instructions:
First, navigate to the USDA Geospatial Data Gateway webpage.
Next, click the Get Data button on the right side of the page (see below).
On the next page that comes up, please click the ‘HERE’ button to change the method for selecting the area. Once you have done this, please select the last option “Order by Interactive Map – Custom Area of Interest (AOI).” This allows you to select a custom area of interest by drawing a rectangle over the area. .
This will open an interactive map. Zoom to your AOI; here I will select Assateague Island National Seashore. Once you have zoomed into your area, use the Select Area button at the top of the interactive map to draw a rectangle. Once you have drawn your area, you will see the Finish Area button appear at the top of the interactive map. Click this to accept the area.
Next click Accept Area at the bottom of the dialog (see above). This will open a new page where you can select the data to be downloaded. Scroll down to the Topographic Images section and check all that you wish to download. In this case, I will select my only download option. Once you have finished selecting data, click the button at the bottom of the page.
On the next page, select the FTP download option at the bottom of the page and select .
This will prompt you to fill in some contact information. When you’ve finished filling in this information, click to move to the final step. On the next page you will have a chance to review your order before confirming by clicking . When your order is ready, you will receive an email and be able to download it.
Your data will be delivered as one or more compressed county mosaics in MrSid format. It may be necessary to clip the image(s) to your park’s area of interest.
This blog posting was developed with the support of a competitive grant (cooperative agreement number P09AC00212; task agreement number P13AC00875) from the National Park Service in partnership with the North Atlantic Coast Cooperative Ecosystems Studies Unit. It is part of a larger document available for download on the IRMA Portal.