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8429176e RN |
1 | <?xml version="1.0"?> |
2 | <!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" | |
3 | "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" | |
4 | [<!ENTITY appname "Viking">] | |
5 | > | |
6 | ||
7 | <section id="GeoRef" xreflabel="GeoRef"><title>GeoRef Layer</title> | |
8 | <para> | |
9 | This layer allows one to use any image as a map. You will need to tell it how to align the map to a position in the world and the scale of map. | |
10 | </para> | |
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11 | <para> |
12 | When a new image is selected the values from a <ulink url="http://en.wikipedia.org/wiki/World_file">World File</ulink> will automatically be tried to be found. | |
13 | (subject to the setting in <xref linkend="prefs_external"/>) | |
14 | </para> | |
15 | <note> | |
16 | <para> | |
17 | &appname; does not currently support skew values and since World Files do not contain what coordinate system the coordinate values are in - &appname; assumes they are in UTM. | |
18 | </para> | |
19 | </note> | |
20 | <para> | |
21 | If you do not know the scale of the map but know the coordinates of both upper left and lower right coordinates, | |
22 | you can enter these coordinates (Lat/Lon only) and then use the <guibutton>Calculate MPP values from coordinates</guibutton> button. | |
23 | </para> | |
24 | <para> | |
25 | The map once loaded can be repositioned via <xref linkend="georef_tools"/>, which may be easier than trying to edit the raw property values. | |
26 | </para> | |
27 | ||
b200bb91 | 28 | <section><title>Layer Properties</title> |
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29 | <para> |
30 | Configurable properties: | |
31 | </para> | |
32 | <itemizedlist> | |
33 | <listitem> | |
34 | <para>The map image file.</para> | |
35 | </listitem> | |
36 | <listitem> | |
37 | <para>X + Y Scales in metres per pixel.</para> | |
38 | </listitem> | |
39 | <listitem> | |
40 | <para>Coordinates of the upper left corner of the map (either UTM or Lat/Lon value).</para> | |
41 | </listitem> | |
42 | <listitem> | |
43 | <para>Alpha. Control the Alpha value for transparency effects using a value between 0 and 255 with the default being 255 for a fully solid image, whereas 0 is transparent.</para> | |
44 | </listitem> | |
45 | </itemizedlist> | |
46 | </section><!-- Prop END --> | |
47 | ||
8429176e RN |
48 | <section><title>Layer Operations</title> |
49 | <section><title>Zoom to Fit Map</title> | |
50 | <para> | |
51 | Automatically set a zoom level to see the entire map coverage. | |
52 | </para> | |
53 | </section> | |
54 | ||
55 | <section><title>Goto Map Center</title> | |
56 | <para> | |
57 | Center the viewport on this map. | |
58 | </para> | |
59 | ||
60 | </section> | |
61 | <section><title>Export to World File</title> | |
62 | <para> | |
63 | Opens a file save dialog to save the scale and position information as a <ulink url="http://en.wikipedia.org/wiki/World_file">World File</ulink>. | |
64 | </para> | |
65 | </section> | |
66 | </section> | |
67 | ||
68 | </section><!-- End GeoRef --> |