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Training Reports for TWF Investigators




















Rodriguez photo

Americo Rodriguez, M.S.

Affiliation

Instituto Nacional de Salud Publica
Centro de Investigacion de Paludismo (C.I.P.)
Tapachula, Mexico

Project and Training Dates

Insecticide resistance in the malaria vector Anopheles albimanus in the coastal plain of Chiapas, Mexico
April - May 1997

Goal

Generate "crop-insecticide resistance risk", insecticide wash-out corridors, and susceptible/resistant gene flow maps for Chiapas study area. This final products will be useful in decision making for the selection of new insecticidies for malaria control, as well as for the selection of the most appropriate resistance management program.

Background

As a result of a selection process, insecticide resistance appears after several generations of mosquitos have been exposed to insecticide chemicals. This resistance can vary depending on the spraying dose and the frequency of applications. Therefore, resistance levels detected at the present time are the result of applications carried out over several years. Considering this, the historic cropping pattern needs to be established. Archived Landsat scenes are to be used to map historic crop cover.

Objectives of CHAART Visit

  1. Receive Training in Image Processing and GIS
  2. Develop land cover classifications of the Chiapas study area for two dates of Landsat TM data

Accomplishments during Visit

Sections of the ERDAS Imagine tutorial were worked through to learn the use of this software for image processing. Subsequently, two Landsat scenes of the southern portion of the study area from August 1989 and October 1993 (originally acquired by the Di-Mod Project and currently archived at Ames) were co-registered using control points. Supervised and unsupervised classifications were performed. For these preliminary products, broad vegetation classes were identified because detailed ground data that would allow more specific landcover labeling were not available at the time. In addition, the entomological data were organized for input into a GIS.

Future Activities

Classifications will be transferred to TNTMips, an image processing software used at C.I.P. in Tapachula. The final labeling of classes will be conducted using historic information on land use from the Secretary of Agriculture in Mexico. Images for the northern portion of the study area must also be acquired to map the entire study area.

Last updated: 9 Feb 1998.