Gamit software

Open a linux terminal, and run the following commands each one will download a small amount of data from the internet :. We have to install old versions of the compilers: 4. Caution, this can overwrite your existing C and Fortran compiler! You will need to email someone with permission who can tell you the password.

If no person from your institution has permission, you can email the GAMIT authors at MIT to obtain a free academic license: see here for more details.

Note that 'prompt noprompt' turns off interactive prompting, to allow you to download many files without being asked about each one. Now, we have the software ready to install. This takes a while, because it is compiling all the code from the source. If you followed all the steps above correctly, it should run OK. Almost done. This file is large, about MB.

Recall that 'prompt noprompt' turns off prompting optional here, since there is only one file , and 'bin' is required to avoid corrupting the file. If you want to use the VMF1 grids for removing hydrostatic delays, you can also use mget vmf1grd. Once this download completes, you should be ready to run! Reducing the size of the Virtual Machine disk. If you have added and then removed a lot of data, you may find that the. VDI file has inflated to be much larger than the space you are actually using.

You can follow these steps to reduce the size of the. The estimates appear on the left side of the screen for the Azimuth directions shown on the plots. The estimates text may be removed by clicking them. Multiple estimates will stack in the same location on the plot.

File and Save buttons allow the information about the profile to be saved. The output of the above profile can be found here. Residual button will plot the residuals to the profile fit. To replot the original profile, select the Fit button. The POP stays green while ever there are profiles still plotted on the figure. Clicking the Offset button will remove offsets from the primary and secondary velocity fields same offset for both fields.

If there are numerical values in the box next to the Offset button, these will be applied to the field for example after a field is loaded.

If the original velocity fields are in different frames the GLOBK utility program velrot can be used to align them before viewing in velview. If the box is empty, either by erasing its contents or by using the clear button , a click and drag box is used to select a square region from which the weighted-average value will be computed.

A text window appears on the figure showing the statistics of the fit plus these results are written to the Matlab window. Clicking the text box will remove it from the screen.

The align button computes offsets between the secondary and primary velocity fields as simple additions to the North, East and Up velocities. For small areas, these offsets will account for frame differences between the two fields.

For larger areas, the velrot program should be used before hand to bring the fields into alignment. If the box next to the button is empty, a click-drag technique us used to select the area in which the alignment parameters are computed. If the site names match the secondary and primary fields, these sites are used to compute the alignment.

For sites in the area that do not have matching site names, sites within the separation distance are used. If the site separation is set to zero then only sites with the same names will be used in the alignment. The output written to the figure window can be removed with a click in the window. The RmDups button is used to remove duplicate site names that are within specified separation and that have the same velocity.

The duplicate sites are removed and will not appear in output files. The Stats button computes the statistics of the differences in velocity for nearby sites within the separation distance and writes the results to the Matlab window.

Only the sites in current view are used to compute the statistics of the differences. A file, Diff. The screen output may be removed by clicking on it. Allows the primary and secondary velocity fields to be swapped. This is useful when making profiles since only the primary field velocities are shown on the profile plots. These buttons allow the page setup paper orientation, fitting of the figure on the page to be set. The print button prints the figure using the arguments given in the box next to it.

Some typical options are:. NN is dots per inch with 72 being appropriate from screen resolution. The -noui option needs be used in the executable version. This option removes the GUI controls from the printed output. When run under Matlab, the functionality of these boxes is available under the file menu.

The velocity vectors plotted by velview are active in that clicking on a vector brings up a menu box that can be used to get information about the velocity vectors. The menu items here each have an action. The top line shows the site name and the field it is from F1 is the primary, F2 is the secondary. Clicking on the site name will make the box disappear and no other actions will take place.

LabelOnFig will write information about the site position and velocity on the figure near the site name. Clicking on this label will make it disappear. LabelPopUp will write the same information but on a new window that will appear in the upper right corner of the computer screen. This window may be destroyed using the normal close window techniques.

TimeSeries will launch tsview for this station see Tsview section. If this field is blank then the current directory will be used. Delete will delete the site from the velocity field and the figure. There is no undo feature. If a site is accidentally deleted, the field will need to be re-Loaded.

Aim: The primary aim of tsview is to assess the quality of time series generated by GLRED runs and to generate control files for GLOBK that will delete bad site position estimates and account for jumps in time series. Time series files can be globk multibase format -year option or PBO time series format globk output option pbo and tssum or tscon. PBO files are assumed to have a. Only one type of file in a directory can be used i.

When the PBO format is used different analyses can be compared. Tsview cannot internally change the reference frame and so time series comparison should use the same frame definition.

Tsfit can be used to change reference frames and generate new time series files. If tsview is launched from velview than the time series of the station selected will be loaded initially provided the directory is set correctly. The basic sequence in tsview is to select a site in the left window, then Load , possibly Append another site, and then Detrend. The O box next to the Append button allows and offset to be applied between the two time series to align them.

This is useful when data from different sites are appended. The edit buttons can remove bad data and the break button can be used to add breaks. A globk earthquake file can be read to automatically add breaks and earthquakes that would be used by globk. There are tool-tips on the buttons to help users with the operation of the program. The ParkEX.

On this figure, the red line show log postseismic breaks from the San Simeon and Parkfield earthquakes , the black line is a simple earthquake offset due to Hector Mine. Blue vertical lines are exponential decay postseismic jumps. Green vertical lines would be offsets due to antenna, radome or receiver changes none shown here. The box at top of the screen allows the specification of a directory where the time series files are located. The name is typed in text box and dir pressed to load the names of the sites in the directory.

This loads the data from the selected site. There are three header lines on the file and second line is used to determine total value of the component being plotted. The format of the file name i. Alternatively PBO format may be used where all components appear in one file.

An example is shown below:. First Epoch : Last Epoch : Release Data : XYZ Reference position : NEU Reference position : Appends another site's data onto previously loaded data.

This option may be used multiple times to append several site names. Most often append is used to re-connect sites that have different names due to earthquakes and renames in GLOBK. Other buttons on the screen determine the precise operations during appends. By default, Break on Append Brk on Append button is set which means that a break is automatically added at the end of the last data set loaded or appended. For this feature to work correctly, data must be loaded and appended in time order.

Since the symbols used to plot the data change with each append, the breaks in data can be found by looking at the symbols. The other option on append is to check the O box next to the append button which will calculate and remove an offset between the original and appended data based on overlapping data times. Statistics of the overlap are written to the Matlab Window. Normally Break on Append would be turned off during this operation.

Removes a linear rate and offsets at breaks plus any parameters set in the Parameter Set box see below. During the detrend operation, the conditions on the maximum sigma of the coordinate estimates Max Sigma box will be applied, and the detrend will be iterated to remove outlier data based on the Max Outlier box. The default all setting will not apply a n-sigma edit. Small values of this condition can lead to all data being deleted. The sigma used in the condition is scaled by the NRMS fit to the linear trend.

The results of the parameter estimates are written to the Matlab window and appear in a figure in the top-right hand corner of the computer screen.

One sigma error estimates for the model fit are shown as thin red lines on the plot after detrending. Edit allows individual points to be deleted from the time series. Using right-click keeps tsview in edit mode to allow multiple points to be edited. Allows areas to be selected for editing using a click and drag technique. Block edit must be re-selected to allow multiple blocks to be edited.

Allows times for breaks to be graphically selected. The List of breaks currently active appears in the Delete Break popup menu. A simple offset break is displayed with a green vertical line.

Allows specification of an exponential fit to a break at the time of an earthquake. The final selection can be edited with the edit break button below. The estimated offset is the co-seismic offset.

The exponential term is the accumulated post-seismic motion. Allows specification of a logarithmic function to be fit after an Earthquake. Similar to the exponent file except the click and drag selects the start of the data to be used in the logarithmic fit and time normalization of the logarithm fit allows the curvature of the logarithm function to be controlled.

Normally the drag direction is to the left. The start of the bar at the bottom shows the start time of the logarithmic function.

A logarithmic break is displayed with a vertical red line and a thick horizontal line show the time constant to the logarithm function. The logarithm fit uses a natural logarithm LN with years as the time argument,. Displays a dialog box that allows the break characteristics to be edited. Breaks are deleted using the Delete Break button explained below.

The type of break can be changed with this option. All times are given as year month day hour min. Time constants are in days. Standard Matlab zoom feature that allows areas of individual components of the time series to be viewed. Double clicking should un-zoom the view.

Allows a span of time to shown click and drag box. All components of the original are re-displayed. In this view, the time series is not detrended. Save operates with the boxes below the station names. Three types of outputs can be saved depending on whether the W buttons write are set next the file names by default all three file types will be written. When checked, the breaks from previous loads are retained when new sites are loaded.

This is a popup menu that shows the dates of the breaks being used. If one of these is selected, then it will be removed. If you are a student, you must also include the name and email of your advisor or other permanent staff member who will receive the announcements and be responsible for the terms of the license. Please also send an e-mail to Dr. King , as described above, to be added to the mailing list. GAMIT " G NSS a t MIT " is collection of programs to process phase data to estimate three-dimensional relative positions of ground stations and satellite orbits, atmospheric zenith delays, and Earth orientation parameters.