GPSeismic FAQs - General

GPSeismic FAQs

Google Earth Support

I don't know if you already have Google Earth but for the purpose of this FAQ, I'll assume you don't.

Google Earth is a free application from Google. Its about an 11MB download. You can use it to interactively zoom in to any location on earth. Using high resolution imagery on web servers, it allows you to get a great perspective on cities, countryside, etc. It relies on you having a fairly fast internet connection. Cable modem speed is fine. In short, its a really cool application.

What we have done in GPSeismic is to utilize Google Earth in a couple of applications, GPSQL and NGSearch. In NGSearch, you can read NGS data files, select a monument you want and press a button that launches Google Earth and 'flies' you to the point. In GPSQL, you can select a query and view the points in Google Earth.

Both applications rely on the fact that you have downloaded and installed Google Earth (again its free).

Now, a few technical facts. First, the imagery used in Google Earth is all based on latitude/longitude in the WGS84 datum. It works out well for GPSQL because your first prompt is for what fields you want to use for location, the default being your WGS84 coordinates. Second, the underlying mechanism for making Google Earth display locations is to construct what is called a KML file and pass that on to the application. The file has a very specific format that must be followed. You can save this file and email it to someone who has Google Earth installed. They can double click it and presto, he's flies to the prospect. Lastly, there is no real upper limit on points. 50,000 points doesn't seem to be too much of a burden.

For planning, it's a great tool. Most imagery I've seen is quite good. You could use your preplots for pre-planning and postplots for seeing where the final locations were placed.

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Protection Error 103

Q - I see Protection Error 103 when I try to run an application. What do I do?

A - This is a strange error we have not been able to get much information on. However, based on what we know, if you uninstall GPSeismic, then re-install, making sure that you have administrative privileges and absolutely nothing else running, it will cure the problem.

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Do you have a tutorial?

A - Yes. Download the GPSeismic Overview (2MB) which is in Word 2000 format. You can use the tutorial with the sample files that our installation program places in the Sample Data directory.'

If you just want a general overview of capabilities, you might wan to look at the GPSeismic Overview video from our FTP site, Overview of GPSeismic Applications (31 MB)

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How can I work in 2 zones?

A - GPSeismic has no capability of automatically transforming points into two different zones. Even if it did, you probably wouldn't want to do this since mapping would appear to show line 'bends' and mis-ties. You have two choices.

The first is to choose the zone in which the majority of the prospect or line exists and live with the resulting scale factor and convergence.

The second is to create your own TM projection and use a non-standard Central Meridian that falls along the center of the prospect or line and perhaps choose 1.0 for the CM scale factor value. If you choose the second option, you should make sure that the client has no problem with coordinates that have a non-standard CM. If they don't, this is your best choice since scale factor and convergence is minimized.'

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Network Capabilities Of Security Keys

The security keys we now use are network compatible. This implies that a user is not required to have the security attached to his computer and can access a key (license) across a local network and even via terminal services. Please note however that each security key tracks its use and ensures that only one user can access it at a time. So, multiple users can access the same security key ' the only restriction is that one user must finish using GPSeismic with the key before another will be granted access to it.

Each key has a hard limit of one license; however, we do have clients with multiple licenses (keys) who place all of their keys on a single server. Their office staff with local IPs and remote staff via terminal services regularly access licenses (as long as one is available) from the server. License restrictions are as follows:

1) For local users where the key is connected directly to the workstation or where the key is accessed from a server via a local area network, each license (key) allows multiple instances of any combination of the GPSeismic applications for the same user. Regardless of which applications are running, this user would consume one license.

2) For remote users via terminal services, a single instance of any GPSeismic application will consume one license (key).

Note that GPSeismic does not need to be installed on the server. The software that must be installed on the server is the security key driver and server software. This installer is available as a single executable which can be downloaded from our FTP site via:

ftp://ftp.gpseismic.com/security/

Download and run the sole file in this folder (Sentinel_Keys_Protection_Installer.exe) on the server. Once this is complete, you can then attach as many GPSeismic USB security keys to the server as you like. Then on each workstation which has GPSeismic installed, you will need to modify a small XML file in the GPSeismic installation folder (typically C:\Program Files\GPSeismic) called sntlconfig.xml. In this file, between the ContactServer tags you will need to replace localhost with the local IP address of your server. This will tell that installation of GPSeismic to look for a key (license) on the system with the entered IP address.

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GPSeismic FAQs

Several programs won't run

A - 2000 and XP is like Windows NT in that you log on with administrator privileges or as a user. If you log on as administrator and install the software,'you will experience no problems each subsequent time you log on as administrator. If logging on as a user on the same system, several programs will refuse to work. This is because these programs will look in the system's registry (you can think of this as a repository of system operating parameters) for the directory where GPSeismic is installed. This information, called the current user key, will be present when logged on as administrator but will have to be written to the correct registry key appropriate for the logged on user.'' There is a program in the GPSeismic folder called GPSeismicShortcutManager.exe. Its actually there so you can customize what you want to see on the desktop, etc. However, one thing that it does upon startup is to write the installation path to the current user key. So if you are experiencing the problems described here, log on normally as whatever user you are, then start this program and then exit. The application path will be written to the current user key and everything should then function normally.'

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Some tool buttons are missing

A - If tool buttons or menu items go missing, you could find the menu or miscellaneous setting that preserves your tool bar settings and turn this off. Re-starting the program should fix it. However, if the situtaion is so bad, you can't do this, you can simply delete the file that saves these changes.

Each applications creates and subsequently uses its own configuration files. If you need to, you can delete these files manually through Explorer, but make sure you delete the right ones. here are the applications and the file(s) you should delete:

QuikLoad - quikload.wsp
QuikView - quikview.wsp
QuikMap - quikmap.wsp
GPSQL - gpsql_mnu.xml and gpsql_dock.xml
QuikCon - quikcon_mnu.xml and quikcon_main_mnu.xml
GPArc - gparcnet_mnu.xml
GPNav - gpnav_dock.xml

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What is unit variance?

GPS systems guess at a position based on the ranges they observe. The ranges don't intersect at a common point. The differences between computed point and observed ranges are the residuals. Ignoring the specific math and talking in very general terms, the unit variance is the ratio of the residuals to their estimated noise.(...by the way, no one better email me and lecture me on the real formula..I know what it is.)

Now think about this. Shouldn't the average of the residuals always be about what the estimated range noise is? The answer is Yes which means the unit variance should always be about 1. A lower number would mean the residuals are less than the estimated noise, or in other words, the system is doing better than what is expected of it.

A higher number means the residuals are larger than the estimated noise. How can this happen. Multi-path is a possibility but there is another possibility. Perhaps the estimated range noise is much smaller than it really is! Herein lies the problem in using the unit variance as the last word in positioning. Its that one little word...'estimated'.

If the system can do this well, the unit variance is going to be a value you can hang your hat on. But if the system does not estimate noise well, then the statistic is meaningless.

Precision values are computed as a function of DOP and estimated range noise. DOP is quite accurately computed, but range noise is estimated. Again, quite meaningless unless the noise is accurately calculated.

Have you ever seen a '-1' for a 95% precision value in the database? Whenever QuikView opens a new file, it initializes all precision values to negative one immediately prior to importing the file. This means that whenever you see '-1.0' for the 95% precision value of a point in the database, there were simply no statistics associated with this point for QuikView to pass along.

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Uninstalling GPSeismic

When you uninstall GPSeismic, only the files that were installed will be removed. This means that if you created a project, every file that was created in the process will still be there after uninstalling. Also, after installing and using GPSeismic, various parameter files are created. These remain as well.

To completely remove all traces of GPSeismic from your system, you will need to do the following:

1) Choose Add/Remove Programs from Control Panel and select GPSeismic to uninstall. This will uninstall most all of the GPSeismic programs, libraries, documentation, sample data, and all registry entries.

2) Reboot so that any programs which were in use during the uninstall will be freed. If you have created projects and need to backup this, do it before the next step.

3) In Explorer, delete the GPSeismic installation folder which is typically C:\Program Files\GPSeismic.

4) Also in Explorer, go to the Windows folder (normally C:\Windows) and sort the files by Type. Scroll down to the files of type INI (Configuration Settings), and look for and delete QuikLoad.ini, QuikView.ini, QuikMap.ini, GPSQL.ini, QuikCon.ini, GPMap.ini, QuikEdit.ini, and Projman.ini.

At this point, your system will then be ready for a clean install of GPSeismic with one exception. T here is a registry section which also has GPSeismic parameters. You can remove this if you feel comfortable in doing it (the registry is a scary place). The section is

HKEY_CURRENT_USER/Software/DynamicSurveySolutions')

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Transferring projects

If you want to transfer all project settings (including queries) then we have to explain a bit about what files are important. When you create a project, there are 5 files created in the database folder. The rest of the folders are initially empty The files are as follows:

'LOG' ' a chronological history of every processing step with regards to that project
'MDB' ' the database
'SET' ' a compressed file of all application settings (including GPSQL queries)
'PRJ' ' a small binary file defining coordinate and datum selection for the project
'UHF ' used to construct a history of what has been uploaded

On the system that reflects the latest settings, you can do the following in Project Manager:

1) Click on the current project and select 'Backup Current Project Settings' Select the project SET file when prompted. This makes sure the latest settings are now contained in the SET file.

2) Click on the current project and select 'Backup Project'. This prompts with a dialog that allows you to basically make a zip file containing a parent folder and all sub-folders. You can accomplish the same thing by just clicking on the project folder and using Window's utility.

3) Unzip the project folder on the computer(s) you want. There's a utility for that in Project Manager as well.

4) On the new computer, start Project Manager and select 'Import Project' from the project menu. It requires you to select the MDB file.

5) Click on the project that now appears on the list and select 'Restore Project'. This action makes the project the current one on that computer with all relevant settings.

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GPSeismic FAQs

TM Snyder projection

Q - A client is asking for a Transverse Mercator Snyder projection as distinct from a standard TM projection. My understanding is that OGP (EPSG) guidelines recommend formulae for projections to be used are from John Snyder's paper, Map Projections- A working manual. So I assume the TM projection in GPseismic use these formulas and therefore the TM and the snyder TM are basicaly the same thing. Can you please confirm.

A - Our transformation libraries do support the Synder projection as defined in the paper 'Map Projections ' A Working Manual'. You will need to create a new System within a Group and use the Space Oblique Projection. Do not use the standard TM projection type. Here is some additional documentation on using this projection:

The Space Oblique Mercator (SOM) projection is a modified cylindrical projection with the map surface defined by a satellite orbit. The SOM is an extremely complicated projection. The SOM projection was designed especially for continuous mapping of satellite imagery.

The ellipsoidal form with a non-circular satellite orbit is implemented . You will need to define the following parameters:

False Northing and False Easting
Longitude of the Central Meridian
Semi-major Axis of the Satellite Orbit
Eccentricity of the Satellite Orbit
Longitude of the Ascending Node
Length of Time of the Earth\'s Rotation
Time of Revolution of the Satellite
Inclination of the Satellite Orbit
Longitude of Perigee relative to the Ascending Node')

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How do I find missing points?

1) QuikMap Method - Start QuikMap. Use 'Open Initial File' on File menu to input your preplot QLD file. Then use 'Open Secondary File' on File menu to input your postplot QLD. Next select 'Compare/Offsets' from the File menu to perform a comparison of the two layers. This results in all preplots which have matches turning red. The green represents all points which have no match (i.e., have not been surveyed). Also, a line will connect all points that have matches.

3) You can create a file of points of any category of points (green, red or blue) by choosing the 'Outputs' item from the File menu. On the resulting dialog, select the file option (default) and press OK. Note on the next file dialog, you can drop down the list at the bottom and create any type of file you want including a QLD. Also, on the Outputs dialog, there is a reports button, press it and you will get a spreadsheet of offset information.

1) GPSQL Method - Assuming your postplots are in the database and you have selected a query representing the sources that have been surveyed, choose 'QuikLoad UHF' from the Query menu. Create a UHF file in the same directory as the preplot QLD file and with the same name. Then start QuikLoad. Before importing your preplot QLD file display the Miscellaneous dialog and check the option to 'Use the UHF file to flag QLD points as being uploaded'.

3) Now import your preplot QLD file. All points which have a match (are surveyed) will be green and cannot be selected for upload. All red are selectable (and represent unsurveyed). On a day by day basis you can replace the UHF file with a new current one from GPSQL. This method provides a efficient way of uploading just what has been surveyed.

Note that you put the preplots in the database by opening the preplot QLD file in QuikLoad. You can cancel all prompts to create any upload file. Finally, select 'Database' on the File menu. On the resulting dialog, choose the option to place the preplots in the database. The UHF method does NOT rely on this, but there are other GPSQL routines that are available if the preplots are present.

QuikLoad Method - On the UHF History File tab page of the Miscellaneous dialog, check the 'Auto create UHF file...' item and design a query that selects your postplot points

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Tell me about Tiff Images

We create world files according to the ERSI spec as described in the following:

Esri world file document

ArcMap and ArcView handle registration differently as described in:

Esri registration document

Image registration data can be in one of two places:

1) In a world file whose extension for a TIFF image is TFW,

2)In the header of what is known as a GeoTiff. All the GPSeismic applications use the data from the world file to register an image regardless of whether the image is a GeoTiff.Curiously, ArcMap will attempt to locate the GeoTiff data first and only use the world file if the GeoTiff info is not present, whereas ArcView will look to the world file first. If for example ArcMap correctly renders an image while ArcView does not. We suspect that these images are GeoTiffs and that the world file that is being created is in a different system than the embedded data. Our suggestion would be to use the following option in the GPSeismic registration utility:

Convert GeoTiff Information to World Registration File

This will ensure that the world file is identical to the embedded header data in the GeoTiff. Another possibility as to why some other applications would reject the world files which GPSeismic is creating is because our mage registration utility will create world files that exactly match the user entries. This means that the X scale and Y scale may not be identical (ignoring sign) and therefore, technically, the image is not rectified (the first article refers to this). Therefore, it may be that these other applications require the world file to reflect a rectified image, and will reject the world file if this is not the case.

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How do you compute area?

A - You can do this in QuikMap, QuikLoad and QuikView. In these applications, when you right click on a point displaying information for it, you are also storing the point in memory.

With this in mind, if you are careful to click on points more or less defining the boundary of the project (maintaining a consistent clockwise or counter-clockwise direction), you can select 'Cogo' from the View menu. On the third page of the Cogo dialog, press the button which adds all points to the area computation list. Then press 'Compute Area'.

There is also a new tool in QuikMap to compute a bounding polygon for a set of points. Once this is created, you could import the polygon into GPMap or GPArc. There are measure and identify tools that can compute the area. For more information on QuikMap's 'encompassing polygon utility', see the following video:

QuikMap Video

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Database change in V2007?

A - In going from v2006 to v2007 we increased the width of four text fields near the end of the POSTPLOT table ("Download File", "Collector Job Name", "Receiver Type", and "Receiver SN"). When QuikView v2007 populates these fields it will automatically change the field widths so that they are all 32 characters wide.

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