<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Hi Lily,<div><br></div><div>Yes, if you want topography on your maps, you need to install and configure a GMT grid of topography. A Google search will lead you to various sources (use the terms "GMT" and "topography" in your search). If you can't find something that works for you, many people use the SRTM30 Digital Elevation Model (DEM). Attached is a program that will convert the DEM files to GMT .grd files. You can then use grdcut and grdpaste to stitch together a grid file that covers your region of interest. </div><div><br></div><div>Also, how are you providing your Vs30 grid? If you have a grid, great, but if not, you can use the USGS Vs30 server: </div><div><br></div><div><span class="Apple-tab-span" style="white-space:pre"> </span><a href="http://earthquake.usgs.gov/hazards/apps/vs30/">http://earthquake.usgs.gov/hazards/apps/vs30/</a></div><div><br></div><div>Note that the GMT grid you get may be have pixel-node registration, and ShakeMap requires gridline-node registration. You can fix the file using grdsample:</div><div><br></div><div><span class="Apple-tab-span" style="white-space:pre"> </span>grdsample your_vs30_grid.grd -Gnew_file_name.grd -T</div><div><br></div><div>Make sure your topography grid covers at least the area of your Vs30 grid.</div><div><br></div><div>Finally, you can combine both of these operations into one step (sort of) by getting the SRTM30 data, converting it to .grd with the attached program, configuring include/macros by setting DEMDIR to point to your SRTM30 directory, and configuring grind.conf so that "qtm_file" is unspecified. This will make a Vs30 grid on the fly. You will also then want to run the program "mapping" with the option -gsm, which will use the DEM data for topography.</div><div><br></div><div>Attached is <a href="http://dem2grd.pl">dem2grd.pl</a>. You will need to edit it and set a couple of paths at the top of the file to point to the right places.</div><div><br></div><div>Hope this helps,</div><div>Bruce</div><div><br></div><div></div></body></html>