Help Help Help Help I am a GRASS beginner.
I need some help from the GRASS community concerning the following:
1. General overview of how to use GRASS 4.1
2. Data loading instructions for DMA (ITD) data
Please read on if you think you can enlighten me.
Acronyms
DMA Defense Mapping Agency
DTED Digital Terrain Elevation Data
ITD Interim Terrain Data
UTM Universal Transverse Mercator
Part 1. General overview.
I am new to GRASS and I would appreciate a general explanation of
how to use GRASS 4.1. An example that demonstrates the order in which
processing should be done would be helpful. I just requested the ftp
document grass4.0/documents/grass_doc.wp.Z in the hopes that the manual
is complete enough to walk a beginner like me through GRASS using the
sample Spearfish data.
I currently have the following tutorials:
Performing Boolean Operations in GRASS 4.0:
r.combine Program Tutorial (December 1991)
GRASS 4.0 Map Digitizing Manual: v.digit (December 1991)
GRASS Tutorial: DLG-3 Data Extraction (April 30, 1992)
GRASS 4.0 Tutorial: DTED and DEM Elevation Data Extraction
(December 1991)
GRASS Tutorial: Image Processing (undated)
GRASS 4.0 Inference Engine: r.infer (December 1991)
Performing Map Calculations on GRASS Data:
r.mapcalc Program Tutorial (December 1991)
A Tutorial for "TIGER in GRASS" (December 1991)
Please feel free to reference them or to suggest another document.
Do tutorials exist for GRASS 4.1?
Part 2. Loading DMA (ITD) data.
Last week I loaded GRASS and some DMA (ITD) data on our Sun from tape.
My long range goal is to load the DMA data into GRASS, perform Boolean
operations on the data, and extract the resulting DMA data from GRASS.
For now, I will settle for being able to load the DMA data into GRASS.
I reviewed the DMA data extraction tutorial; however, my data is not
in DTED or DEM format. I have the following data files in ITD format:
hyd_line.add obs_line.add
hyd_poly.add obs_poly.add
hyd_pt.add slope.add
loc_line.add surf_mat.add
loc_pt.add veg.add
According to the README file in my data directory,
% Each file contains data records which represent either points,
% lines or polygons (regions) with the following record format:
%
% 1. Record number
% 2. Polygon Attribute String
% 3. Number of Vertices
% 4. Vertices
%
% Vertices are given in UTM coordinates.
Is ITD format close enough to DTED format that I can trick GRASS into
thinking my data is in DTED format? Do I have to extract the data from
a tape? If the data is already on-line, do I still "extract" it for
GRASS?
Thank you in advance for your help.
Virginia Jackson
Engineering Research Associates
e-mail: jackson@era.com
phone: (703) 734-8800