GeoVisu - Georeferenced data viewer

V 5.0.1


Features Menus Appendix

Table of contents

  1. Display georeferenced data
    1. Data loading
    2. Localization into the graph (geographic) space
    3. Layer management
    4. Image display
    5. Cursor coordinates display
    6. Zoom / Interactive move
    7. Find a place
    8. Geodetic systems
      1. Available systems
      2. System selection screen
  2. Communicating with a GPS receiver
    1. Supported GPS receiver models
    2. Real time navigation (NMEA or Garmin USB)
      1. Manual lauching of navigation
        1. Selecting port and speed
        2. Protocol
        3. Settings to be done on GPS receiver
      2. Navigation log
      3. Automatic launch of navigation when starting
      4. How navigation works
      5. Display track during navigation
    3. Download data recorded by GPS receiver
      1. Download screen
        1. Selecting port
        2. Protocol
        3. Settings to be done on GPS receiver
        4. Selecting GPS receiver
        5. Selecting data to be downloaded and file name
      2. Data storing formats
  3. Graphics data export
  4. Printing
  5. Options and system parameters
    1. Drawing colors of GPS data and Shapefiles
    2. "Map Features" representation
      1. Select and define "features"
        1. OSM
        2. cGPSmapper polish format
      2. Select and define representations
    3. Configuration file
    4. Command line parameters
    5. Harddisk usage
      1. Temporary directory
      2. Reduced images usage
    6. Embedded mode

Geovisu is a program that displays georeferenced data. It also provides real time navigation and data download from GPS receiver.
GeoVisu is available for Windows 2000/XP/2003/Vista/Seven.
This program is free of charge.

I. Display georeferenced data

1. Data loading

"Open" menu is used to select a file for loading. Only files with an extension corresponding to a format that Geovisu can display are proposed.

Another way is to drag and drop either one or several files, or a directory.
When loading a directory, Geovisu loads every image files of this directory (and all sub-directories) that are georeferenced into the same geodetic system, and every graphic file.
The way graph space geodetic system is selected is documented in section 2. One way to efficiently load images, is to group all images having the same geodetic system in one directory, and load that. This directory may have many sub-directories.

You can give file names to GeoVisu using the command line. You can put in the command line file names, directory names or Web (HTTP or ECWP protocol) file addresses (cf. paragraphe V.4).

GeoVisu can load files even when the extension doesn't correspond to the format of the file. GeoVisu automatically recognizes file format.

GeoVisu also reads compressed files (Gzip and ZIP) directly.

2. Localization into the graph (geographic) space

Aim of GeoVisu is to display together georeferenced data coming from different sources.

Data are displayed with their exact geographic position. They are displayed using layers.

Display is done using a given geodetic system. (What we call a geodetic system, can either be a system of geographic coordinates OR projected coordinates.)

The geodetic display system is set

Bitmap transformation is not possible with GeoVisu. That's why, when an image is loaded, it is not possible to dynamically change the geodetic system. And thus, it is not possible to load images having different geodetic systems.

The size of the graph space is the one of the whole displayed data. The graph space is included in the geographic space.

3. Layer management

Graphic and image layers are managed in tree structure.

A file has always at least one layer.
For KML/KMZ files, sub-layers are defined in the file.
For OSM or Polish format, layers are created for each «Map feature».

Layers may be activated or deactivation using «Graphic layers management» screen.

Graphics are displayed over images. Images are displayed according to their resolution (most accurate on top).

4. Image display

"Monochrome" and "Negative" options can be applied to image display.
Monochrome option displays images in a given color, keeping luminosity values.
Negative option inverts luminosity values. Dark pixels become light, and light pixels become dark.

5. Cursor coordinates display

Cursor coordinates can be displayed into a geodetic system and unit selected by user (system selection screen).
Geodetic system and unit in which coordinates are given are displayed in the title bar of coordinate window.

6. Zoom / Interactive move

Menus and key functions give access to zoom change.

Double click on left button is a positive zoom. Double click on right button is a negative zoom.
In these cases, the point under the mouse position doesn't move.

Move around the graph space can be done using

7. Find a place

Find place name screen allows you to do a query on the name or comment of an object.

The object types on which the search applies are :

You can use '*' or '%' to replace any substring.
The query is not case sensitive.

Examples : to find "rue" or "avenue" "des Champs Elysées", you can enter, for example :
%champs%ELYSEE% or *ue*Champ*élÿse*

Attention : On the contrary, extra characters will cause the search to fail.
Example : avenue des champs elysees paris won't find Avenue des Champs Elysées in Paris, since paris in not part of the name of the street.

"Find" button displays the list of found names.
Once place names have been found, use «Localize» button to go to the place you selected in the list.

Localization is immediate, whithout exiting dialog box.
However, no zooming is performed.
If you don't see element you're looking for, you may have to click in the graphic window and do some zooming in (F1 or '+' or left double-click).

8. Geodetic Systems

a. Available systems

GeoVisu geodetic systems are described into files ellipsoi.txt, pmeridian.txt, datum.txt, gcentric.txt, cartproj.txt, ellipsil.txt, pmeridil.txt, datumil.txt, gcentril.txt, cartpril.txt. If any of these files are missing or incorrect, GeoVisu doesn't work.

Data Source :
GeoVisu integrates geodetic systems given by EPSG v6.11, Mapinfo v7.8, ERMapper v2, Garmin and has additional systems.
Parameters given by these editors have been validated by GeoVisu team. This validation is mainly based on documentation published by national geographics institutes.

Coordinates Conversion :
To transform coordinates from one system to another, GeoVisu uses the geocentric coordinates transformation (Helmert or Bursa-Wolf or Molodensky-Badekas) with 3, 7 or 10 parameters.

Cartographic Projections :
A global verification and validation of ellipsoids, datums and geocentric transformation has been performed. This verification has not been done yet for projections.
In appendix B there is a list of supported projection methods.

Display / Graph Space :
When working with geographics coordinates, graph space is included into the geographic space, i.e. the whole world. With projection coordinates, graph space is included into the area that corresponds to the projection. (Some projections transform some points to one infinite. We limit the domain of graph space).
Objects outside the graphic space are not displayed. (It is especially the case for UTM zones.)

b. System selection screen

System selection screen has three selection zones :

A selection in one of these zones is copied into a button. You have to click on this button to validate selection ("Enter" key has same effect).
In some cases, when opening this screen, the button contains the last selected system.

II. Communicating with a GPS receiver

1. Supported GPS receiver models

GeoVisu has been tested with the following models :

Data download Garmin GPS II Plus,Garmin Forerunner 301, Garmin Quest,
Magellan Sportrak, Emtac Trine, GlobalSat DG-100,
Transystem iBlue 747, SJA Travel Honey, Wintec WBT-201,
Locosys GT-11, Locosys GT-31, Royaltek RCD-1100.
PVT navigation Garmin Quest, Garmin GPS 18.
NMEA navigation Garmin GPS II Plus, Magellan Sportrak, Haicom Hi-204 III, Emtac Trine, GlobalSat DG-100,
Lowrance GlobalMap 100, Royaltek BlueGps RBT-3000, Evermore GT-600, eBontek eGPS-597, Transystem iBlue 747,
Wintec WBT-201, Locosys GT-11, Locosys GT-31, Royaltek RCD-1100, SJA Travel Honey.

2. Real time navigation (NMEA or Garmin USB)

a. Manual lauching of navigation

If Navigation option is already checked, Navigation menu stops navigation. Otherwise, it launches navigation screen.

i) Selecting port and speed

Proposed ports are :

For every USB GPS receiver whose driver creates a virtual COM port, or for a software like GPSGate emulating a virtual COM port, you must choose "COM port".

Port typeThings to do
COM Port
virtual COM port
(usb-serial or GPSGate)
User has to enter port number in the input box and must select speed that actually corresponding to GPS issue speed.
USB GarminUser can select GPS receiver if it is already connected.
UDP PortYou have to choose port number (predefined port 7551 or 7552, or number entered by user in the input box).
UDP ports are used by GpsDiffuser.

Only one GPS receiver or port can be selected at a time.

In all cases, you can start navigation even when GPS receiver is not connected or port does not exist.

ii) Protocol

Protocol is automatically set to Garmin PVT for Garmin USB, and to NMEA in all other cases.
Other protocols are not supported yet.

iii) Settings to be done on GPS receiver
GPS receiver model Settings to be doneRemarks
Serial Garmin Please select the right protocol : NMEA/NMEA 4800b
USB GarminThere is nothing to set. GeoVisu starts PVT emission.
MagellanSpeed must be the same as the one selected in screen. GeoVisu automatically starts NMEA emission.
Royaltek RGM-3800 Speed selected in screen must be 115200b. GeoVisu automatically starts NMEA emission.
Royaltek RBT-2300, RCD-1100 Speed selected in screen must be 57600b GeoVisu automatically starts NMEA emission.
Globalsat DG-100 1. Speed selected in screen must be 115200b.
2. It seems that, for Globalsat DG-100, navigation is no longer possible after downloading log ; you have to switch the GPS receiver off and then on.
GeoVisu automatically starts NMEA emission.
Other GPS receiversNMEA emission must be started by user (or by default).
Speed must the same as be the one selected in screen.

Attention : geodetic system information is generally not transmitted by standard NMEA protocol.
Non-Garmin GPS receivers must either be set to WGS84 system (recommended), or be configured to issue NMEA sentence $GPDTM.

If there is no data before starting navigation, GeoVisu automatically sets the graph space to that of the GPS receiver (generally WGS84).

b. Navigation log

There is an option to log sentences received from GPS receiver into a NMEA file.
This option can be switched on and off either using "Log navigation" menu, either by the same name checkbox in navigation screen.

The log files are stored in navigation log directory (see configuration file). Default log directory can be opened using GeoVisu Start menu.

In case of NMEA GPS receiver, these are raw sentences received from GPS receiver ; Garmin PVT protocol is converted to NMEA sentences, some of them being Garmin proprietary.

It is not possible to log data received on UDP port.

c. Automatic launch of navigation when starting

When GeoVisu is launched using command line, or by a shortcut, it is possible to start automatically real time navigation, with or without log.
To do this, you have to give an argument among the following :

Examples :

"C:\program files\geovisu suite\geovisu.exe" -NAVIGLOG COM3 -NAVIGPORTSPEED 9600
"C:\program files\geovisu suite\geovisu.exe" -NAVIG UDP7551

GPS receiver does not need to be connected, neither port needs to exist, before launching GeoVisu.
As soon as GeoVisu can open port and receives data, it will navigate.

It is therefore possible to launch automatically navigation (on a given port) when starting the computer, by placing such a shortcut in the "Startup" menu of Windows.

d. How navigation works

When 'Real time navigation' is checked, and GPS data with position are received, GeoVisu automatically sets current position at center of the window ("moving map"). All graphics and bitmap data are moved to keep the current position at the center of the window. A symbol (red circle) is displayed at the current GPS position.
Note : This function is not really compatible with interactive mouse move. But positive and negative zoom are still allowed.

If there is no data before starting navigation, GeoVisu will set graph space geodetic system to the one of the GPS receiver (generally WGS84).

Real time navigation disables downloading of waypoints, tracklogs, routes.

e. Display track during navigation

There is an option to display or not the track carried out during navigation.
Color can be modified dynamically using "Colors and fonts" menu.

4. Download data from GPS receiver

Waypoints, tracklogs and routes recorded by a GPS receiver can be downloaded and saved to files.

a. Download screen

Waypoint/tracklog/route download screen has 3 parts.

i) Selecting port

Proposed ports are :

For every USB GPS receiver which driver creates a virtual COM port, you must choose "COM port".

For COM port, user has to enter port number in the input box.
However, speed is automatically selected by GeoVisu according to the GPS receiver.

ii) Protocol

GPS protocol must be selected by user.

Supported protocols are :

ProtocolGPS receiver model Downloadable dataNotes
GarminEvery Garmin receivers waypoints, tracklogs, routes Garmin is automatically selected when choosing USB Garmin
MagellanEvery Magellan receiver without a memory card waypoints, tracklogs, routes 
Emtac TrineEmtac Trine datalog 
Globalsat DataLoggerGlobalsat DG-100 and BT-338 datalog 
Mediatek MTKEvery GPS receiver based on MTK chipset
including :
Transystem iBlue 747 and iBlue 757, Qstarz BT Q-1000, iTrek Z1
datalog (+ push-to-log points) 
SkytraqEvery GPS receiver based on Skytraq chipset
including :
Sja Travel Honey, iTravel-Tech, KeyMate STV-5, Navilock BT-455PDL, Canmore GT-730F(L)
datalog (+ push-to-log points) 
Navilink Locosys GT-11, BGT-11, GT-31 et BGT-31, Scytex NaviGPS, Amaryllo Trip Tracker waypoints, tracklogs, routes, datalog 
Wintec Wintec WBT-201 / G-Rays II, WPL-1000 et WGS-1000 / G-Trender datalog (+ push-to-log points) Downloading waypoints from WGS-1000 is not supported
Royaltek Royaltek RGM-3800, RBT-2300 et RCD-1100 datalog 1. Records of type "4 and 5" of the last RGM-3800 firmware are not supported
2. POIs from RCD-1100 are not downloaded

Nethertheless, tests have not been done on every existing GPS receiver models (see section 2.1).

iii) Settings to be done on GPS receiver
Protocol Settings to be done on GPS receiver
Serial Garmin Please select the right protocol : Garmin/Garmin 9600b in Host mode.
MagellanSpeed must be set to 4800b.
SkytraqSpeed must be set to 9600b.
Other GPS receiversThere is nothing to set.

Before downloading, GeoVisu automatically stops NMEA sending from GPS receivers, and sets it back at the same status at the end of downloading.

iv) Selecting GPS receiver

Then, user has to click «Probe GPS» button.
A list containing detected GPS receivers is then filled for selected protocol(s).

GeoVisu proposes a list containing every connected GPS receivers that are able to transfer waypoints, tracklogs, routes.

Choosing a GPS receiver in the list sets activable checkbox(es) for data types (waypoints / tracklogs / routes) that this GPS is able to provide (some GPS receivers don't store data).

v) Selecting data to be downloaded and file name

When at least one of the waypoints / tracklogs / routes checkboxes is checked AND a file name is filled, «Download» button becomes active.

User can then click «Download».

A progressbar shows download progress. Displayed information depends on GPS receiver model.

After downloading, data are displayed ; if data deletion has been chosen, a confirm message is displayed before.

As said above, downloading is not available during real time navigation.

b. Data storing formats

Generated file formats are :

Garmin GVW, GVT, GVR GeoVisu proprietary described in appendix C.
GVN GeoVisu proprietary described in appendix C.
Emtac Trine
Raw logs, in NMEA format.
Raw logs, containing NMEA sentences and also binary data.

For more information, see Appendix C.

For Garmin and Royaltek GPS receivers that store several tracklogs, GeoVisu will generate one file per tracklog downloaded from GPS receiver, and also one complete file containing all tracklogs.
For the first ones, name chosen by user will get a suffix which is _t followed by the number of the track.

III. Graphics data export

Geovisu can export

A file is generated for each layer (or loaded file). The name of saved file is the name of the loaded file with the new extension (.mif .kml .gpx .nmea) added.
Example : file1.gtm exported to file1_gtm.nmea

Note : you can upload GPX files generated by GeoVisu to OpenStreetMap site, and also used them with editor JOSM.

IV. Printing

Printing function prints all data displayed in GeoVisu window.
Note that if only one part of the document is displayed in the window, only this part is printed and not the whole document.
The document is printed in full page mode.

Print options are :

Printer name This is used to select the printer.
Printer resolution (dpi) This is used to select the printer drawing smoothness.
This doesn't change the size of the printed document.
(applies to bitmaps only)
This is used mainly when printing document that contains bitmaps and vector graphics, to emphasize them.
Ratio This is used to reduce the size of the printed document. Range value is 1 - 100.
Font size This is used to modify the size of all printed texts by applying a multiplying factor.
Thickness This is used to modify all graphics thickness by applying a multiplying factor.

V. Options and system parameters

1. Drawing colors of GPS data and Shapefiles

Some file formats (SHP and some GPS files) don't contain color and/or font size information. User can choose colors and/or font sizes that will be used to display data coming from files loaded afterwards.

On the other hand, for real time navigation, it is immediately taken into account.

2. "Map Features" representation

Map features representation screen is made of two parts.

Attention :
1) In this version, changes are not saved (they are lost when exiting GeoVisu).
2) Changes do not apply to file that where loading before calling the screen.

a. Select and define "features"

Words "map features" applies to objects from formats OSM and Polish format (cartographic elements).

i) OSM
In the case of OSM objects, you can associate to each couple (keyword, value) a "node" (point representation) and/or a "way" (line or surface representation).
ii) cGPSmapper polish format

In the case of oPolish format objects, you can associate to each couple (type, subtype) a "POI" (point representation), a "POLYLINE" (line representation) or a "POLYGON" (surface representation).

b. Select and define representations

Right area of this screen allows you to modify display attributes of point, line or area representations.

Point, line or area representations are defined by default by GeoVisu in XML files.
They do not depend on the file format from which are the objects.

Every change in display attributes of a representation applie to every objects that are associated with this representation.
(For example, every OSM objects of type "highway/primary" and every Polish Format objects of type 0x300.)

However, it doesn't modify display of files that are already loaded.

3. Configuration File

Configuration File contains some GeoVisu parameters.
These parameters are:

Parameter SyntaxUse
Screen background colorBACK_COLOR_RGB 255 255 255 This parameter determines the red, green and blue levels of the background color. Possible values are integers between 0 and 255.
A gray level is obtained by three identical values.
Default value is 200 200 200.
Temporary directoryTEMP_DIR c:\temp\geovisu This parameter sets GeoVisu temporary directory
(cf. paragraph V.3.a).
Reduced images directory REDUCE_IMAGE_DIR c:\geovisusmall This parameter gives reduced images location (see section V.3.b).
GeoVisu language
(english or french)
This parameter allows to change GeoVisu language (english or french).
By default, GeoVisu takes into account operating system language.
Real time navigation log directory LOG_DIR c:\nmea This parameter allows you to modify navigation log directory.
Embedded mode EMBEDDED TRUE This parameter activates embedded mode (cf. paragraph V.6).
Memory limitation MAXMEM value This parameter limits the memory size to be used. Value is in megabytes (Mb).
Example : MAXMEM 200
Web access method HTTP PROXY proxyname portnum
Examples :
  • GeoVisu uses specified proxy and port number to connect to the Web.
  • If line HTTP is not present, GeoVisu connects to the Web without using proxy.
  • If line HTTP is present with something else than PROXY, GeoVisu does not connect to the Web.
    Example : HTTP NOT

geovisu.cfg file is available from GeoVisu Start menu. It can by modified using a text editor.
Lines beginning with # are comments.
An example file (geovisu_exemple.cfg) is provided in the GeoVisu install directory.

4. Command line parameterse

When run using command line or shortcut, GeoVisu can have the following parameters :

Parameter SyntaxUse
Load file-LOAD "file_name" Use this parameter to load a file or a directory.
The name may be a web address (http or ecwp).
This parameter may be used as many times as there are files to load.
Example : -LOAD "c:/directory" -LOAD ""
Navigation automatic launch -NAVIG port_name
-NAVIGLOG port_name
-NAVIG launches navigation on selected port.
-NAVILOG launches navigation and log on selected port (except UDP).
Port name syntax is : COMx UDPx USB where x is the port number.
Example : -NAVIG UDP7551
(cf. paragraph II.2.c).
COM port speed -NAVIGPORTSPEED speed Use this parameter to set COM port speed in baud. It is an integer value.
This parameter is mandatory for COM ports when using -NAVIG COMx or -NAVILOG COMx.
This value must be equal to the GPS issue speed (cf. paragraph II.2.a.i).
Embedded mode -EMBEDDED TRUE This parameter activates embedded mode (cf. paragraphe V.6).
Log directory -LOG_DIR "directory" Use this parameter to set log directory.
Example : -LOG_DIR "c:/nmea"
Max memory usage -MAXMEM value Use this parameter to limit memory usage. Value is in mega-bytes.
Example : -MAXMEM 200
Configuration file path -CONFIG_FILE "file_name" Use this parameter to set absolute path of the configuration file, if different from the default one.
Example : -CONFIG_FILE "G:/geovisu/geovisu2.cfg"

If the first string of the command line is a file name, it is interpreted as a load file parameter.
Example : "C:\program files\geovisu suite\geovisu.exe" "c:\fichier1.shp" means "C:\program files\geovisu suite\geovisu.exe" -LOAD "c:\fichier1.shp"

5. Harddrive usage (except in embedded mode)

a. Temporary directory

GeoVisu writes some temporary files into the directory TEMP_DIR (from geovisu.cfg). This is done whilst there is space available on the disk. Files are deleted when GeoVisu exits.
This temporary directory can be modified by TEMP_DIR declaration in configuration file (geovisu.cfg).

b. Reduced images usage

Reduced images improve display time of undersampled images.
These reduced images are built automatically by GeoVisu.
For the reduced image function to be used by GeoVisu, you must declare the REDUCE_IMAGE_DIR directory in the configuration file.
This function creates, in the REDUCE_IMAGE_DIR directory, directories, sub-directories and files which name is a number and the 'mof.sot' file. In case of problem or to do cleaning, you just have to completely empty the REDUCE_IMAGE_DIR directory. This operation should only be done when GeoVisu is not running.
The size of the created files is 1/100 of the size of uncompressed image.
Only images in format GeoTIFF are concerned by this function.

6. Embedded mode

When running in embedded mode, no data are written to disk, except for real time navigation log.
All data are kept in memory. You have to take care that you have enough RAM quantity for your usage. If there is not enough memory, application will be stopped.

Embedded mode is especially suitable for netbooks.

Features Menus Appendix