Display Background Images in Topcon Tools

The Map and CAD View displays a background image for a work area. Topcon Tools can open only georeferenced image as a background. (Georeferencing of the image establishes the relationship between pixel coordinates and real datum/grid/ground/local coordinates).

If the image is not georeferenced, Topcon Tools can calculate the relationship with the desired coordinate system. To do this, the user has to have the coordinates of the ground control points in the given coordinate system.

I will often use Images from Google Earth to use for my background. In Google Earth I zoom to the desired area for my background and export the image to a JPG format. I will then import and georeference the image in Topcon Tools using the Background Images tools. Remember to do this properly you will need to have coordinates on identifiable points in the image. If you want to create a quick georeferenced image you can get the Lat/Lon coordinates for points in Google Earth and use them create points in Topcon Tools. Convert the Lat/Lon coordinates in Tools to your plane coordinate system (State Plane, UTM,...). This is a nice trick but can be a little drawn out. Hopefully Topcon Tools will soon come up with an automated Google Earth to background image, like AutoCAD, in the future. Below is some detail information from the Topcon Tools user manual, but it is much easier to import an image and georeference than what the manual indicates.   To add a vector or raster image as background to the current job, do the following:

1. Click View > Background images.

2. Click the Add Image button in the Background images dialog box

3. Select the Add Image Button

Select the desired image file in the Open dialog box, and then click Open. This image will be displayed in the left panel (Available Images) of the Background images dialog box. An unlimited number of images can be activated in this panel.

4. Select the needed background image in the left panel and click the double arrows button. This image will display in the right panel (Images used in the jab) of the Background images dialog box. If the coordinate system of the selected image is the same as the job’s coordinate system, this image will be marked with a green icon in the right panel and displayed in the Map and CAD views.

                                                                            

5. Be sure that the Show Background Map entry box is checked (enabled) for the Map/CAD View (To see this check box, right-click on the Map/CAD view, then select Option from the pop-up menu).

View Video Here 

Resources for Finding or Establishing Survey Control

Internet Resources

Most governments will have an agency assigned to maintain a Spatial Reference System to meet economic, social, and environmental needs. Control networks may consist of “hard” monuments that are physical monuments, such as brass caps or chiseled marks on concrete, or “virtual” monuments such as Continuously Operating Reference Stations (CORS). Both will have horizontal or vertical values that reflect the national reference system or vertical datum. Not all nations share the same reference system which can be confusing at times, as there are several kinds of realizations of global geodetic reference systems. Differences among these realizations are caused by slight differences of realized mass centers of the earth, adopted reference ellipsoids and plate motions.

Below are some resources for finding or establishing horizontal or vertical control.

National Geodetic Survey (NGS) - NGS provides the framework for all positioning activities in the Nation. The foundational elements - latitude, longitude, elevation and shoreline information - contribute to informed decision making and impact a wide range of important activities including mapping and charting, flood risk determination, transportation, land use and ecosystem management. NGS' authoritative spatial data, models and tools are vital for the protection and management of natural and manmade resources and support the economic prosperity and environmental health of the Nation. http://www.ngs.noaa.gov/


CORS – NGS manages a network of Continuously Operating Reference Stations (CORS) that provide Global Navigation Satellite System (GNSS) data consisting of carrier phase and code range measurements in support of three dimensional positioning, meteorology, space weather, and geophysical applications throughout the United States, its territories, and a few foreign countries.

Surveyors, GIS users, engineers, scientists, and the public at large that collect GPS data can use CORS data to improve the precision of their positions. CORS enhanced post-processed coordinates approach a few centimeters relative to the National Spatial Reference System, both horizontally and vertically.

The CORS network is a multi-purpose cooperative endeavor involving government, academic, and private organizations. The sites are independently owned and operated. Each agency shares their data with NGS, and NGS in turn analyzes and distributes the data free of charge. As of November 2011, the CORS network contains over 1,800 stations, contributed by over 200 different organizations, and the network continues to expand. http://www.ngs.noaa.gov/CORS/

NGS Data Sheets - Part of the mission of the National Geodetic Survey, is to
provide the public with survey control information, such as Latitude, Longitude, Height and Gravity Data. This is done for publishable stations in the form of DATASHEETS. http://www.ngs.noaa.gov/cgi-bin/datasheet.prl


Online Positioning User Service (OPUS) - OPUS provides simplified access to high-accuracy National Spatial Reference System (NSRS) coordinates. Upload a GPS data file collected with a survey-grade receiver and obtain an NSRS position via email.

OPUS requires minimal user input and uses software which computes coordinates for NGS' Continuously Operating Reference Station (CORS) network. The resulting positions are accurate and consistent with other National Spatial Reference System users.

Your computed NSRS position is sent privately via email, and, if you choose, can also be shared publicly via the NGS website. http://www.ngs.noaa.gov/OPUS/

The NASA Global Differential GPS (GDGPS) System - GDGPS is a complete, highly accurate, and extremely robust real-time GPS monitoring and augmentation system.

Employing a large ground network of real-time reference receivers, innovative network architecture, and award-winning real-time data processing software, the GDGPS System provides decimeter (10 cm) positioning accuracy and sub-nanosecond time transfer accuracy anywhere in the world, on the ground, in the air, and in space, independent of local infrastructure. http://www.gdgps.net/


Automatic Precise Positioning Service (APPS) – APPS offers instant positioning supporting GPS and GLONASS observations. APPS supports file formats in RINEX 2 and RINEX 2.11. Processing Modes include Static and Kinematic. All coordinates are reported in ITRF 2008. http://apps.gdgps.net/apps_file_upload.php


Scripts Orbit and Permanent Array Center (SOPAC) - SOPAC archives high-precision GPS data, particularly for the study of earthquake hazards, tectonic plate motion, crustal deformation, and meteorology. SOPAC calculates and provides precise near real-time and predicted GPS satellite orbits and determines precise polar motion and Earth rotation variations. SOPAC allows users to generate precise coordinates for their input RINEX files using the Scripps Coordinate Update Tool (SCOUT). SOPAC is an International GPS Service (IGS) Global Analysis Center

SCOUT - The Scripps Coordinate Update Tool (SCOUT) can be used to compute mean coordinates of a specific site, by submitting a RINEX file of a particular day. The file may be uncompressed, or in .Z, .gz or .bz compressed format. Both standard observation (o) and hatanaka-compressed (d) files are accepted.

Local Resources

City Engineering Offices – City Engineering offices manage public works projects and construction. The City Enginering office will often have elevation benchmark information and horizontal control networks for the City and local area. Beware though, as City benchmarks may become dated or no longer tied to a known reference datum.

Transportation Departments – Transportation offices can be found at City, County, State and Federal levels. Transportation Departments and are a great resource for transportation maps and related horizontal and vertical control networks. Many offices will have an archive of printed and microfiche plans. Transportation engineering and survey departments will also have topographic maps, aerial imagery, control network information and GIS data.

Water and Utility Departments – Water and utility departments manage the resources and assets that are valuable to the area they serve. Water and Utility departments are a good resource for underground utility and waterline maps. Many have GIS departments that keep maps up to date. Water and utility maps are not usually available via the internet due to security issues.


Airports - Airports can be a valuable resource for vertical control benchmarks. Most have been surveyed to determine a precise elevation for landing air traffic. Benchmarks can often be found at runway ends at public and military airports.

The Geoid and Geoid Models

The Geoid and Geoid Models Review

The geoid is that equipotential surface which would coincide with the mean ocean surface of the Earth, if the oceans and atmosphere were in equilibrium, at rest relative to the rotating Earth, and extended through the continents (such as with very narrow canals). A geoid is the "mathematical figure of the Earth", a smooth but highly irregular surface that corresponds not to the actual surface of the Earth's crust, but to a surface which can only be known through extensive gravitational measurements and calculations.

1=Ocean; 2=Reference ellipsoid; 3=Local plumb line; 4=Continent; 5=Geoid

The gravity field of the earth is neither perfect nor uniform. A flattened ellipsoid is typically used as the idealized earth, but even if the earth were perfectly spherical, the strength of gravity would not be the same everywhere, because density (and therefore mass) varies throughout the planet. This is due to magma distributions, mountain ranges, deep sea trenches, and so on.

If that perfect sphere were then covered in water, the water would not be the same height everywhere. Instead, the water level would be higher or lower depending on the particular strength of gravity in that location.

Source: NGS, Wickipedia

NGS Geoid09

GEOID09 is a refined hybrid model of the geoid in the United States and other territories, which supersedes the previous models GEOID06, GEOID03, GEOID99, GEOID96, GEOID93, and GEOID90. This model is intended for converting between the NAD83 ellipsoid reference frame and vertical datum NAVD88, GUVD04 (Guam), ASVD02 (American Samoa), NMVD03(Northern Marianas), PRVD02 (Puerto Rico) and VIVD09 (Virgin Islands).

http://www.ngs.noaa.gov/GEOID/GEOID09/

NGA EGM2008

The official Earth Gravitational Model EGM2008 has been publicly released by the U.S. National Geospatial-Intelligence Agency (NGA) EGM Development Team. This gravitational model is complete to spherical harmonic degree. Full access to the model's coefficients and other descriptive files with additional details about EGM2008 are provided at the NGA website.

Those wishing to use EGM2008 to compute geoid undulation values with respect to WGS 84, may do so using the self-contained suite of coefficient files, FORTRAN software, and pre-computed geoid grids provided on the NGA website.

http://earth-info.nga.mil/GandG/wgs84/gravitymod/index.html

Create an Area in TopSURV

Use existing points to create an Area

1. Open the edit Area menu.

2. To add an Area, tap ADD in the bottom right corner. Give the Area a name. Using the SELECT PTS pull-down menu select From Map. Select the points in numerical order (or in an order that creates a closed area).

3. Tap CLOSE when finished.

4. Define the Layer states (if needed). Tap CLOSE from the Add Area window to store the Area.

5. Tap CLOSE from the Area menu to complete.

Areas are simple closed lines formed by points.

View the Area in the Map

The map shows points connected into a line and the area that can be filled with the selected style.