Ia. Creation of 1954 DEM

In the 1950’s basic topographic mapping of Guatemala was completed by the Instituto Geográfico Nacional (IGN) and country-wide 1:50,000 quadrangle maps were compiled.   The maps are based on aerial photography from January- March 1954, for Santiaguito and Pacaya (IGN, Guatemala, sheets Colombá (1860 II), Retalhuleu (1859 I), San Lorenzo (1859 II), and Amatitlán (2059 II)) had 20 m contour lines, which were digitized from clear film and exported to an ArcINFO export format (.e00) (USGS, 2001).  The United States Geological Survey (USGS) used these 20 m elevation contours to produce 10 m pixel DEMs (pers. comm. Steve Schilling, 2007) following Hurricane Mitch.   The 1954 data includes DEMs, hydrology, transportation, and contour lines.  The original data is in ArcINFO export format (.e00)  and was converted using  ArcToolbox in ArcGIS 9.0 .  All of the data except for the DEMs were converted using the import from interchange file (shown below):

 

 The DEM data was converted using Conversion Tools>To Raster> DEM to Raster found within the ArcToolbox as shown below.  

                 

The DEM to Raster menu allows users to specify float or integer data. The float data type is used when a number is positive or negative and has significant digits, while an integer data type is using an integer with no decimal places.  When importing additional DEM data the floating point option is best to use. Once the interchange and DEM files are converted you may add the data into ArcMap. For the 1954 dataset the coordinate system is UTM zone 15 NAD 1927.  The projection is already added to the DEM and coverage file in this case. The vector .e00 files which were converted to a coverage file format. This file format is slowly being phased out, so the coverage should probably be converted to a shapefile or a geodatabase which can be done in ArcCatalog (discussed later).

Note: The 1954 datasets for Santiaguito and Pacaya have already been converted and is available on the network.  In addition all of the original .e00 files are available on the network if needed. I have only converted the data for the quadrangles encompassing Santiaguito and Pacaya, therefore other quadrangles would need to be converted using the above steps to view the data in ArcMap.
Next the 2001 DEM were converted and these procedures can be found here.