d.out.gpsdrive(1)

1d.out.gpsdrive(1)             Grass User's Manual            d.out.gpsdrive(1)
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NAME

6       d.out.gpsdrive  - Export display monitor to a GpsDrive compatible back‐
7       drop image
8

KEYWORDS

10       display, export, GPS
11

SYNOPSIS

13       d.out.gpsdrive
14       d.out.gpsdrive help
15       d.out.gpsdrive [-j] output=string  [--verbose]  [--quiet]
16
17   Flags:
18       -j
19           Make JPEG instead of PNG image
20
21       --verbose
22           Verbose module output
23
24       --quiet
25           Quiet module output
26
27   Parameters:
28       output=string
29           name for new map image (lives in ~/.gpsdrive)
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DESCRIPTION

32       d.out.gpsdrive exports the current GRASS display monitor to a  GpsDrive
33       compatible  backdrop image and updates the GpsDrive image list with the
34       appropriate geo-referencing information.
35
36       Use at your own risk. Do not use as  a  primary  means  of  navigation.
37       This software comes with absolutely no warranty.
38

NOTES

40       Maps  are  saved  in  the user's ~/.gpsdrive directory. Geo-referencing
41       information is added to the user's ~/.gpsdrive/map_koord.txt file.
42
43       JPEG output requires the  pngtopnm  and  pnmtojpeg  programs  from  the
44       NetPBM tools.
45
46       GpsDrive  assumes northings are not rotated compared to true-geographic
47       north.  If you are using a projection with significant  curvature  away
48       from the central meridian, or a map datum with a significant rotational
49       component, then you will likely end up  with  a  distorted  or  inexact
50       background  map!  Keeping the area small will lessen the error, but not
51       eliminate it.
52
53       Best output is created from a Lat/Lon location or by keeping the output
54       area  small  (1:50,000).  This  translates  to approx a 22.7km x 18.2km
55       image window in the GIS. [x_ext=scale*(1280/2817.95)]
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57       For your convenience (calculations are rough, but nominal):
58       1:50,000 uses a region 22.7km x 18.2km.
59       1:75,000 uses a region 34.1km x 27.3km.
60       1:100,000 uses a region  45.4km x 36.3km.
61       1:175,000 uses a region  79.5km x 63.6km.
62
63       Maps exported from lat-lon locations will be  given  a  "top_"  prefix.
64       Maps  exported  from  locations  of  other  projections will be given a
65       "map_" prefix. This is done so GpsDrive knows how to  scale  the  image
66       correctly.
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68       GpsDrive requires backdrop images to be 1280x1024 pixels in size. While
69       this script takes care of that automatically, to avoid  annoying  bands
70       on  the sides of your image you may want to set up your display monitor
71       at half-scale (same aspect ratio) and use d.zoom  to  select  the  full
72       frame. For example:
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74
75       export GRASS_WIDTH=640
76       export GRASS_HEIGHT=512
77       d.mon x0
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79       Map  scaling  is  set from the region settings so should work correctly
80       even when the display's aspect ratio does not match that of the  output
81       image.
82
83   Batch export
84       It  may be desirable to create a series of image tiles covering a large
85       area.  An easy way to do this is to run d.out.gpsdrive in a shell loop.
86       Here is an example Bash script contributed by Manuel Morales:
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88
89       #!/bin/bash
90       # map scale is determined by "panels" by dividing the N-S
91       # region extent into that number of maps. Note that the
92       # generated maps overlap by 1/2 along the N-S axis and by
93       # approximately 1/2 along the E-W axis.
94       panels=3
95       iter=$((panels*2-1))
96       eval `g.region -eg`
97       eval `g.region -g`
98       north=$n
99       south=$s
100       west=$w
101       east=$e
102       unit_ns=$(echo "scale=8; $ns_extent / $panels" | bc)
103       unit_ew=$(echo "scale=8; $unit_ns * 4/3" | bc)
104       panels_ew=$(echo "((2*$ew_extent / $unit_ew +.5 ) -1) / 1" | bc)
105       for i in `seq 1 $panels_ew`;
106       do
107         east=$(echo "scale=8; $west+$unit_ew" | bc)
108         for j in `seq 1 $iter`;
109           do
110           g.region  n=$(echo  "scale=8;  $north-($j-1)  *  $unit_ns/2"  | bc)
111       \
112               s=$(echo "scale=8; $north-($j-1) * $unit_ns/2-$unit_ns" | bc  )
113       \
114               w=$west e=$east ewres=$ewres nsres=$nsres
115               d.redraw
116               d.out.gpsdrive -j tile_${i}_${j}
117           done
118         shift_west=$(echo  "scale=8;  ($ew_extent-$unit_ew)/($panels_ew-1)" |
119       bc)
120         west=$(echo "scale=8; $west+$shift_west" | bc)
121       done
122
123       Note that to get a  smoother  transition  between  backdrop  maps  this
124       script creates overlapping tiles.
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AUTHOR

133       Hamish Bowman
134
135       Department of Marine Science
136       University of Otago
137       New Zealand
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139       Last changed: $Date: 2007-09-26 02:12:40 +0200 (Wed, 26 Sep 2007) $
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141       Full index
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143       © 2003-2008 GRASS Development Team
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147GRASS 6.3.0                                                  d.out.gpsdrive(1)

NAME

KEYWORDS

SYNOPSIS

DESCRIPTION

NOTES

SEE ALSO

AUTHOR