Datamine Discover KB - Grid Utilities

How do I reproject my data?

Josh Knight — Fri, 19 Nov 2021 07:21:42 GMT

MapInfo and Discover provides a number of different Reprojection Utilities, depending on the type of data to be transformed. Each of these tools will create a copy of the data in the specified output projection, typically with a default _reproject suffix added to the input file name. These tools are invaluable (for example) for ensuring all datasets are in the same Coordinate Reference System (projection).

Note: After reprojecting when you open in back in the map window, it will appear in exact same location. This is due to Mapinfo being a GIS system that reprojects on the fly. It will only appear in a different location when opened in a non-GIS program.

Vector data (i.e. points/polylines/polygons)

This is shown in the layer control with an icon -

There a numerous ways to reproject these -

1. Standard MapInfo way is to go to Home>Save>Save Copy As. Then on the save dialog, click the projection button and choose the new projection.

2. Use the Discover>Reproject>Reproject Coordinates. This uses the Discover projection engine with explicit NTv2 support. (note this doesn't support NativeX tab files).

3. Use the DISCOVER > Reproject > Multi-Table Reproject tool. This allows the current projections of multiple vector tables to be displayed and reprojected, either as new tables, or overwriting the existing tables.

Note with all of these methods only change the spatial vector data in the map. They do not update any coordinates in the browser table for say points. There ...

How do I clip my data to a polygon region?

kbadmin — Wed, 02 Sep 2020 00:36:15 GMT

Discover provides a number of tools to clip your map data to a area within a selected polygon -

1) Vector layers - QUERY>Map Object>Vector Clip
2) Images - IMAGES>Images Tools>Clip Image
3) Surface Grids - SURFACES>Utilities>Clip

Some raster images and raster grids may also be clipped with RASTER>Operations>Clip

How do I add a custom projection to MapInfo and Discover

kbadmin — Tue, 27 Aug 2019 00:10:24 GMT

Occurrence

I've added a custom projection line to my MAPINFOW.PRJ but it does not appear in the select projection dialog box's list.

Solution

If the projection is not appearing in MapInfo Pro, it will need to added to the default MAPINFOW.PRJ file located in -

C:\Program Files\MapInfo\Professional (64-bit)

C:\Program Files (x86)\MapInfo\Professional (32-bit)

Note that these are read only locations, so you will need to copy the file to your desktop, edit it, and then copy back to overwrite with the changes.

If it is still not listed check the format is exactly correct by copying the exact formatting -

"--- Custom name ---"
"Projection name", x, x, x

You should also use DISCOVER>Projection Editor to create the custom coordinate system string.

If using Discover 2017 Update version or later, you only need to update the 1 PRJ file. Other PRJ files are kept in sync. Also there is a new Projection Editor tool to add custom projections, and update both files.

If you wish to share the same PRJ file on a network drive for all users, this can be set using the MapInfo Workgroup directory setting in PRO>Options>Directories.

On older versions, Discover's reprojection tools and Discover3D use a separate projection file (to MapInfo Pro) which you will need to copy and paste the custom projection lines into It has the identical format as the Mapinfow.prj file..
It is located at-

C:\Users\USERNAME\AppData\Roaming\Encom\Common\Projections\Encom.prj

How do I clip my data down to a selected polygon or region boundary?

Josh Knight — Mon, 12 Nov 2018 01:04:25 GMT

Discover provides a number of tools that allow you to clip or cut your datasets down to selected regions/areas. An example would be to provide subsetted datasets to government organisations for lease relinquishment reports, or to a joint venture partner.

The tools are data type specific, i.e. vector, image or grid data:

Vector Data

(e.g. point, polygon or polyline data, such as soil sample or drillhole point locations, surface geology regions, traverse lines and track polyline data)

Use Discover's QUERY>Map Object>Vector Clip tool. This requires the user to select one or more bounding regions/polygons (e.g. the sub-blocks to be relinquished) before running the tool.

Raster Data (e.g. airphotos, landsat imagery)

The Images menu has a Clip Image tool. This provides 2 methods for defining the clip region/area:

1. Select one or more bounding regions/polygons (e.g. the sub-blocks to be relinquished) before running the tool. Within the tool, enable the 'Clip outside polygon' option, and ensure that the 'Polygon Table * Selection *' is selected

2. Within the tool, select the table containing the polygonal areas to clip the image to. All polygons in the specified table or selection will be used for clipping.

Gridded Surfaces

(e. ...

How do I convert an SRTM GeoTIFF image with embedded elevation data into a grid?

Josh Knight — Tue, 22 Sep 2009 06:44:43 GMT

Occurrence

SRTM GeoTIFFs often have elevation data embedded in the image file (e.g from http://srtm.csi.cgiar.org/SELECTION/inputCoord.asp).
Discover can extract this information, creating a grid that can be contoured and manipulated by the Surfaces menu (accessed via the Discover>Surfaces menu option).

Solution

Simply use File>Open>Grid Image .

Alternatively, download SRTM data in an Arcinfo ASCII format, which can also be opened directly from the File>Open>Grid Image.

When I Convert a gridded surface into a Geotiff file, it displays as grayscale

kbadmin — Wed, 15 Apr 2009 23:43:30 GMT

Occurrence

When I convert or export my grid file into a Geotiff, it becomes grayscale and loses it's colouring scheme.

Solution

This is due to the Geotiff grid format being�a multi-banded format.�

If a single banded grid is converted to this, it will become grayscale as it does not contain 3 RGB bands.

You can use the�Grid Utilties>Create RGB tool to create a multi-banded Geotiff grid.

Alternatively the surface grid can be saved as a standard Geotiff raster file using Discover>Map Window>Convert Map to Registered Raster.

How can I set a surface grid data range to display transparent?

kbadmin — Wed, 24 Dec 2008 02:57:26 GMT

Occurrence

The Surfaces>Modify Grid Display tool allows the transparency of an entire grid to be set.
But how can I set only a particular data range of a grid to be transparent?

Solution

You will need to select the option other then Full Grid; so you can clip by Value, Percentage or Percentile.

Enter your desired min/max value to apply Transparency. Then tick the option Set outside min/max to Transparent.