MICRODEM is described as 'freeware microcomputer mapping program written by Professor Peter Guth of the Oceanography Department, U.S. Naval Academy. MICRODEM displays and merges digital elevation models, satellite imagery, scanned maps, vector map data, and GIS databases' and is a GIS Software in the Travel & Location category. There are seven alternatives to MICRODEM for a variety of platforms, including Windows, Linux, Online / Web-based, Mac and Android. The best alternative is QGIS, which is both free and Open Source. Other great apps like MICRODEM are GRASS GIS (Free, Open Source), SAGA GIS (Free, Open Source), what3words (Freemium) and Equator (Freemium).
QGIS, formerly Quantum GIS, is a user friendly open source Geographic Information System (GIS) licensed under the GNU General Public License that runs on Linux, Unix, Mac OSX, and Windows and supports numerous vector, raster, and database formats and functionalities.
GRASS GIS (Geographic Resources Analysis Support System) is an open source, free software (FOSS) Geographical Information System (GIS) with raster, topological, vector, image processing, and visualization functionality.
Spatial Feature Server by MapET is an ESRI Geoservices REST Implementation and works with all ESRI Rest API's. The source of published data is the spatial extension of the major RDBMS, such Oracle, Microsoft SQLServer, MySQL, PostgreSQL.