This Tutorial shows Geodetic and Cartographic Projection Functions of MensorGIS. You learn about
setting Reference Systems (Main, Import/Export)
importing Geo Data having Reference Systems different from the Main one
exporting Geographic Projections as SVG File
the Main System for the Project Data Set which is visualized in the Plot Area;
the Import/Export System for Data to be read from a File or to be written into a File.
the SVG (Scalable Vector Graphics) Format saves the Features only for Graphical Representation;
in MensorGIS different Cartographic Map Projections can be selected (Cylindrical/Azimutal/Conic).
Menu „File - Import - openCartoDB“
select „openCartoDBworld.xml“
answer the Question on Identity Check with „No“
-> 10 Object Classes get created, 3 of them are used (Points *):
„cities“ as red Points of different Size
„peaks“ as black Triangles (Icons)
„sanctuaries“ as black and white Icons
Remark: You may turn the Icons On / Off by using Menus „Cartography - Icons On“ / „Cartography - Icons Off“
Menu „Edit - Texts - Generate from Object Class“ -> Window „Create Text“:
select Object Class „* OCDB_cities“
select Attribute „name“
select Color „Red“
select Size „4“
select Layer „1“
press „Create Texts“
close the Window (OK)
Menu „Reference Systems - Import/Export System“ -> Window „Import/Export System“:
select Type „projected“
select Projection „StatePlane“ (USA)
type in I(dentification)CODE „2001“
select Unit „Meter“
select Datum „Int1980/NAD83“
press „Save“
select Color „Cyan“
Menu „File - Import - ShapeFile“ -> select „MBTA_ARC.shp“
-> Object Class „MBTA_ARC“ containing Railway Lines to Boston/MA gets created.
Menu „View - Limits - Fit Subset“ -> Window „Set Limits“ is shown:
choose the Name of the Regional Data Set just imported (ComboBox at bottom)
-> the Limits get displayed
press „Save“
-> the Region around „Boston“ in Massachussets gets displayed
-> the City Point Feature of Boston is from the World Data Set (no perfect coincidence because the World Data Set has limited accuracy)
You may Zoom in using Button Z+ or Cursor Menu „Zoom In“ to see all Lines in detail and picking a center Point
You may display the Attribute Data using Button Show Attr or Cursor Menu „Show Attr“ and picking a Line Feature
There is one General Projection for the whole World called UTM (Universal Transversal Mercator).
Each Country of the World uses its own local (plane) Projection. Some of these Projections are available in MensorGIS.
The UTM Projection and the Projections of some Countries use different Central Meridians for different Parts of the Country.
The States of the USA use different Projections with different Central Points indicated by I(dentity) Codes.
When you select a certain Projection the default Central Meridian/empty ICODE, the default Units and default Datum are shown.
According to the Data to be used you have to change these Elements; especially be aware that some States use Meter and some use Feet as Unit.
If you want to use a local (plane) Projection as Main System you should set this System appropriately before importing Data Sets.
In the Tools Bar under „Layers“ click into the CheckBox beneath Layer "1" (containing the Text Features) so that the check disappears
-> the City Names disapear
Menu „File - Export - SVG“ -> File Output Dialog of Windows is shown
enter „ProjTutor“ as the File Name (the Extension .svg is added automatically)
press „Save“
-> Dialog „Projection“ is shown:
enter „12“ for the Cylindric Lambert Projection
press „OK“
-> Export of about 3000 Points, Lines and Texts (the Attribute Warning does not matter in this case)
An SVG File can be displayed by many Browsers – at least after Installation of a Plug-In.
The most popluar Cartographic Projections are implemented in MensorGIS.
Cylindric Projections can be used for World Data Sets.
Azimutal and Conic Projections are best for Parts of the World.
Setting the Pole Distance of the Main Latitude and/or the Main Meridian you may adapt these Projections to your need;
You can make these adaptions in MensorGIS using the Menu „Extras - Set Preferences - SVG Map Projections“.
MensorGIS Version 1.1.1, 2012/03/29