GIS Gallery

This page has different thematic images which are needed in hydrogeological studies. The data displayed on these figures are currently stored in the "Valley of Mexico Hydrogeological Database" (VMHDB), which comprises climatological information (e.g. rainfall, pan evaporation, minimum and maximum temperature) as well as run-off and borehole data (e.g. groundwater table elevation and lithology). This information was gathered from different sources and in differente formats which consisted of hard-copy maps and reports. The result of this work are maps at a 1:250,000 scale which are shown here, at a low resolution

The figures shown here were created by using GRASS, GMT, The GIMP and Inkscape. GRASS has been extensively used to import, georeference and digitize the original hard-copy maps as well as to build their topology.

The coordinates of these figures are on meters, UTM zone 14; the grid is displayed at every 10,000 meters.

Topography

The left image shows the Basin's topography. The Basin is enclosed by different mountain ranges with peaks as high as 5500 meters above sea level (masl). The thick black line represents the watershed limit, while the thinner black line represents the political boundaries between the five states located in the Basin: The State of Mexico, the Federal District, Hidalgo, Tlaxcala and Puebla. Coordinates are in UTM Zone 14.

Geology

The Basin is a closed basin, as explained and illustrated in the topography section. This figure shows the surface geology of the Basin and of the mountain ranges that enclose it. At its the southern part is located the Sierra Chichinautzin which is a structure of basaltic rocks from the Quaternary (Qv). At the southeast the Basin is enclosed by the Sierra Nevada which has snow capped peaks all year round; one of these peaks, the Popocatepetl is an active volcano.
This map was created from a hard-copy map at a 1:100,000 scale developed by Mooser et al (1996). The relief map was created from a Digital Elevation Model which was processed with GRASS in order to show the terrain's shadows. These two maps were then exported and processed with The GIMP in order to have a high resolution image with shadow effects inside and outside the watershed. The watershed boundary was created by subdividing the DEM (as it is a DEM at 30 m resolution) and using the r.watershed module of GRASS. The watershed map was converted to a polygon and then exported to The Generic Mapping Tools (GMT) to print it. The resulting files were merged with Inkscape which was also used to add the final touches to each map (e.g. legend and grid).

Extraction and monitoring wells

The Valley's aquifer system is the main water source to the Basin's inhabitants, thus a proprer identification of extraction wells is required in order to improve water management in the Basin.