CREATING A RASTER

CREATING A RASTER - CREATING A RASTER consider laying a...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
CREATING A RASTER consider laying a grid over a geologic map o create a raster by coding each cell with a value that represents the rock type which appears in the majority of that cells areas o when finished, every cell will have a coded value in most cases the values that are to be assigned to each cell in the raster are written into a file, often coded in ASCII o this file can be created manually by using a word processor, database or spreadsheet program or it can be created automatically o then it is normally imported into the GIS so that the program can reformat the data for its specific processing needs there are several methods for creating raster databases Cell by cell entry direct entry of each layer cell by cell is simplest o entry may be done within the GIS or into an ASCII file for importing o each program will have specific requirements the process is normally tedious and time-consuming o layer can contain millions of cells o average Landsat image is around 7.4 x 106 pixels, average TM scene is about
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 2

CREATING A RASTER - CREATING A RASTER consider laying a...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online