14 Replies Latest reply on Dec 3, 2013 12:17 PM by Jamal432@gmail.com

    Accuracy issue in capturing XYZ points with ArcPad installed in Leica CS25,

    Jamal432@gmail.com
      Accuracy issue in capturing XYZ points with ArcPad installed in Leica CS25,

      I tried to capture the XYZ of a known point with our GPS device (Leica CS25 + GG03 Antenna) but the sounds that the captured point is not accurate knowing that this point is real-time differentially corrected. The error is X is about 6 meters while the error in Y is about 8 meters.

      The coordinate system is set to be ???D-Palestine-1923???


      What might be the issue here?

      Thank you

      Best

      Jamal
        • Re: Accuracy issue in capturing XYZ points with ArcPad installed in Leica CS25,
          blackbrett
          If you are using Zeno Connect, do you have a transformation applied that should not be or are you not applying a transformation and should be?
          • Re: Accuracy issue in capturing XYZ points with ArcPad installed in Leica CS25,
            Jamal432@gmail.com
            If you are using Zeno Connect, do you have a transformation applied that should not be or are you not applying a transformation and should be?



            Many thanks Brett for the help,

            I didn�??t apply any kind of transformation.

            The screenshots below shows the coordinates of the known point and the ones I captured by the CS25

            [ATTACH=CONFIG]29333[/ATTACH], [ATTACH=CONFIG]29334[/ATTACH]

            How to know that I need to apply a particular transformation? If the transformation is required, then how to apply it?
            • Re: Accuracy issue in capturing XYZ points with ArcPad installed in Leica CS25,
              mboeringa2010
              What's the source of these written coordinates against which you compare your own coordinates? And when were these measured?

              I am not entirely sure, but I don't think a projection issue is the most likely, as any of the other common coordinate systems in your area would put you off by far more than this (up to a 1000 km due to different False Northings).

              You seem to be using Palestine 1923 / Palestine Grid, other potential logical options in your area are Palestine 1923 / Palestine Belt, Palestine 1923 / Israel CS and Israel TM, but all of these aren't close in terms of FE and FN.
              • Re: Accuracy issue in capturing XYZ points with ArcPad installed in Leica CS25,
                blackbrett
                In Zeno Connect you are able to select your coordinate system as well as any necessary transformation based on your corrections. I do not know specifically which transformation you may need to apply, but I would recommend talking with the real-time network provider or someone familiar with GIS/GNSS field collection in the area to help you work through this issue. I am fairly certain it is a transformation issue, but you will need to either test further by selecting the various transformations available or speak with someone that can further assist.
                • Re: Accuracy issue in capturing XYZ points with ArcPad installed in Leica CS25,
                  Jamal432@gmail.com
                  In Zeno Connect you are able to select your coordinate system as well as any necessary transformation based on your corrections. I do not know specifically which transformation you may need to apply, but I would recommend talking with the real-time network provider or someone familiar with GIS/GNSS field collection in the area to help you work through this issue. I am fairly certain it is a transformation issue, but you will need to either test further by selecting the various transformations available or speak with someone that can further assist.



                  I couldn�??t get sufficient technical support from the reseller of the CS25 device in Palestine and this is why I�??m still struggling with multiple issues.

                  The official coordinate system in Palestine is �??Palestine_1923_Palestine_Grid�?� (but not Palestine_1923_Palestine_Belt or Palestine_1923_Israel_CS_Grid). The point that is shown in the screenshot is measured in this coordinate system (Palestine_1923_Palestine_Grid) and is considered as reference. It is for sure correct.

                  In case that I need to play with the parameters of our projected coordinate system (Palestine_1923_Palestine_Grid) to obtain accurate XYZ coordinates using our GPS device (CS25 + GG03 Antenna), then

                  1. What new values for the parameters of �??Palestine_1923_Palestine_Grid�?� the should I consider?

                  [ATTACH=CONFIG]29370[/ATTACH]

                  2. Is this implemented in ArcPad or ArcMap?

                  [ATTACH=CONFIG]29371[/ATTACH]

                  3. How the transformation is involved in this issue?

                  [ATTACH=CONFIG]29372[/ATTACH]

                  All what I wanted is to capture accurate XYZ points with our CS25 device in �??Palestine_1923_Palestine_Grid�?�.
                  • Re: Accuracy issue in capturing XYZ points with ArcPad installed in Leica CS25,
                    mboeringa2010
                    The point that is shown in the screenshot is measured in this coordinate system (Palestine_1923_Palestine_Grid) and is considered as reference. It is for sure correct.


                    Jamal, although I don't necessarily want to question the quality of the reference, you should always be very critical of both your own, and other's measurements. Even top-notch government organizations here in the Netherlands, who should know better and have checks in place, have had data delivered and initially accepted that ultimately turned out to contain unacceptable positional errors when matched up against later data deliveries from other companies.

                    It is far better, in case of inconsistencies like these you experience now, to assume all measurements could be wrong, until proven right... It is just to easy to make some vital mistake when dealing with surveying, coordinate systems and transformations, as there are many aspects to take into account, just see the articles by Eric Gakstatter I referenced in the "Nightmare in GIS Street" thread for some nice illustrative examples.

                    I know it is not very helpful to you at this point in time, but that is my opinion.
                    • Re: Accuracy issue in capturing XYZ points with ArcPad installed in Leica CS25,
                      blackbrett
                      Jamal,

                      If you are to be using Palestine_1923_Palestine_Grid and you know for certain that your control points are in the same coordinate system, then there is no need to modify anything related to the parameters of your projection files.

                      I said Zeno Connect allows you to setup your coordinate system as well as an associated transformation based on your corrections. Is your Leica representative also the owner of the real-time network you are receiving RTK corrections? They should be able to tell you what coordinate system the real-time network is referencing regardless of which software you are using for field collection.
                      • Re: Accuracy issue in capturing XYZ points with ArcPad installed in Leica CS25,
                        mboeringa2010
                        Jamal,

                        If you are to be using Palestine_1923_Palestine_Grid and you know for certain that your control points are in the same coordinate system, then there is no need to modify anything related to the parameters of your projection files.


                        X2.

                        Good points Brett, I agree there shouldn't be need to modify projection details. Custom projections are only necessary in very rare cases, and this isn't one of them. There may be an issue with transformations, as you justly pointed out and I also suspect.

                        I said Zeno Connect allows you to setup your coordinate system as well as an associated transformation based on your corrections. Is your Leica representative also the owner of the real-time network you are receiving RTK corrections? They should be able to tell you what coordinate system the real-time network is referencing regardless of which software you are using for field collection.


                        The RTK may be in Israel TM grid, as that is the current CRS (coordinate reference system) for Israel. Jamal may have more info.
                        • Re: Accuracy issue in capturing XYZ points with ArcPad installed in Leica CS25,
                          Jamal432@gmail.com
                          X2.

                          Good points Brett, I agree there shouldn't be need to modify projection details. Custom projections are only necessary in very rare cases, and this isn't one of them. There may be an issue with transformations, as you justly pointed out and I also suspect.



                          The RTK may be in Israel TM grid, as that is the current CRS (coordinate reference system) for Israel. Jamal may have more info.


                          Thank you Macro.

                          That might be correct. The reseller in Palestine is probably connected to the RTK of an Israeli company called etkes. I have sent them an e-mail and I�??m waiting there answer.

                          At the same time, I don�??t think that the RTK is based on the Israeli grid as the difference between the Israli TM and Palestine Grid 1923 is 50,000 in X and 500,000 in Y. For example, the (160000, 170000) in Palestine Grid is equivalent to (210000, 670000) in Israli TM

                          The captured XYZ coordinates at the �??control point�?� is only few meters away from the precise one (as it shown in the previous screenshot)
                          • Re: Accuracy issue in capturing XYZ points with ArcPad installed in Leica CS25,
                            Jamal432@gmail.com
                            Jamal,

                            If you are to be using Palestine_1923_Palestine_Grid and you know for certain that your control points are in the same coordinate system, then there is no need to modify anything related to the parameters of your projection files.

                            I said Zeno Connect allows you to setup your coordinate system as well as an associated transformation based on your corrections. Is your Leica representative also the owner of the real-time network you are receiving RTK corrections? They should be able to tell you what coordinate system the real-time network is referencing regardless of which software you are using for field collection.


                            Hi Brett,

                            1. In the �??zeno connect�?�, there are 4 transformations (attached) for our coordinate system (Palestine_1923_Palestine_Grid)
                            �?� Palestine 1923 (1)
                            �?� Palestine 1923 (2)
                            �?� Palestine 1923 1X
                            �?� Palestine 1923 2X

                            What might be the appropriate one? Till now, I didn�??t get an answer from the company

                            [ATTACH=CONFIG]29448[/ATTACH],

                            2. Sounds that there is no way to choose the coordinate system\transformation directly from the ArcPad the same way we do it in the �??zeno connect�?�. Is this an issue?

                            [ATTACH=CONFIG]29449[/ATTACH]


                            3. Is the mountpoint also relevant to the accuracy?

                            [ATTACH=CONFIG]29450[/ATTACH]
                            • Re: Accuracy issue in capturing XYZ points with ArcPad installed in Leica CS25,
                              blackbrett
                              Jamal,

                              You are likely going to have to test each transformation against known control to better gauge which is the correction transformation. I am not familiar with your coordinate system, real-time network, etc. so I cannot help there.

                              If you are using Zeno Office/Zeno Office on ArcGIS and Zeno Field, your transformations are setup in your Survey Dataset/Survey Project. the coordinate system tab you highlighted in Zeno Field is only for the geoid model, which is applied in the Survey Project along with a transformation, if needed. If you are using Zeno Connect with Esri ArcPad, then the transformation is handheld in Zeno Connect. Note that ArcPad and Zeno Field are similar applications, but Leica's Zeno Field enables advantages to high-accuracy field data collection.

                              Mountpoints are defined by the real-time network provider. Each mountpoint is a unique product and you must select one compatible with your GNSS hardware. RTCM is utilized by most, if not all, GNSS equipment, including Leica. If you are receiving a phase-fixed solution and roughly 1cm accuracy, your parameters are set correctly for your real-time network. From there, it is based on the coordinate systems and transformations being applied.
                              • Re: Accuracy issue in capturing XYZ points with ArcPad installed in Leica CS25,
                                Jamal432@gmail.com
                                Jamal,

                                You are likely going to have to test each transformation against known control to better gauge which is the correction transformation. I am not familiar with your coordinate system, real-time network, etc. so I cannot help there.

                                If you are using Zeno Office/Zeno Office on ArcGIS and Zeno Field, your transformations are setup in your Survey Dataset/Survey Project. the coordinate system tab you highlighted in Zeno Field is only for the geoid model, which is applied in the Survey Project along with a transformation, if needed. If you are using Zeno Connect with Esri ArcPad, then the transformation is handheld in Zeno Connect. Note that ArcPad and Zeno Field are similar applications, but Leica's Zeno Field enables advantages to high-accuracy field data collection.

                                Mountpoints are defined by the real-time network provider. Each mountpoint is a unique product and you must select one compatible with your GNSS hardware. RTCM is utilized by most, if not all, GNSS equipment, including Leica. If you are receiving a phase-fixed solution and roughly 1cm accuracy, your parameters are set correctly for your real-time network. From there, it is based on the coordinate systems and transformations being applied.



                                Thank you Brett for the very useful answer.

                                Please, find below the answer I got from the company. What do you think?

                                ------------------------------
                                1.      If you haven't use the "zeno out" process, the transformation doesn't update with the shape files in zeno filed.
                                When you just copy-past shape file to the tablet you should generate the transformation file, using the "datum transformation configuration tool"
                                Here you have a  video, explaining how to do it:
                                https://www.sugarsync.com/pf/D0459014_62440860_854568
                                You can also generate a one-time project in zeno office, export it to the tablet using "zeno out". And the transformation will update to the all future projects.

                                2.      In zeno connect The transformation can be editing according to your own preference. I've attached picture with the values that I have. Please check before using them.
                                But, if you are using "Carlson" software, all the coordinate system Is already pre-define in it. So you don't need to use the zeno connect coordinate system settings.

                                3.      The zeno field using an old version of the NMEA module, so there is still no coordinate systems configuration embedded in it. Zeno connect using the new version so the configuration is there.
                                • Re: Accuracy issue in capturing XYZ points with ArcPad installed in Leica CS25,
                                  blackbrett
                                  If I am understanding the response correctly, this looks accurate to me.

                                  The most efficient way to take data to the field when using Zeno Office/Zeno Office on ArcGIS and Zeno Field is to utilize the EasyOut/In process. From your geodatabase the process creates an EasyOut folder with the necessary files files to be utilized in Zeno Field on your CS25 unit. Once field collection is completed you start an editing session and EasyIn the field data.

                                  If using Zeno Connect and ArcPad, you will utilize the ArcPad Data Manager, which is a similar process to the EasyOut/In process, however, the Survey Dataset and Survey Project allow for transformations, CSCS files and geoid models.
                                  • Re: Accuracy issue in capturing XYZ points with ArcPad installed in Leica CS25,
                                    Jamal432@gmail.com
                                    If I am understanding the response correctly, this looks accurate to me.

                                    The most efficient way to take data to the field when using Zeno Office/Zeno Office on ArcGIS and Zeno Field is to utilize the EasyOut/In process. From your geodatabase the process creates an EasyOut folder with the necessary files files to be utilized in Zeno Field on your CS25 unit. Once field collection is completed you start an editing session and EasyIn the field data.

                                    If using Zeno Connect and ArcPad, you will utilize the ArcPad Data Manager, which is a similar process to the EasyOut/In process, however, the Survey Dataset and Survey Project allow for transformations, CSCS files and geoid models.


                                    Thanks Brett,

                                    For me, I�??m using ArcMap\ArcPad\Zeno connect,

                                    1. I do use the �??ArcPad data manager�?� to include all the layers in one apm file
                                    2. I open the apm file from the ArcPad and then to capture points

                                    This doesn�??t produce accurate XYZ capturing

                                    The second feedback I got from the company is to:

                                    1.  replace the two files (DefaultTransforms.dbf and transforms.dbf) available on the C:\Program Files\Leica Geosystems\Leica Zeno Field\System with the ones provided by the company
                                    2. add the shape file to the Zeno field and then to capture points

                                    [ATTACH=CONFIG]29543[/ATTACH], [ATTACH=CONFIG]29544[/ATTACH]

                                    This doesn�??t produce accurate XYZ capturing neither

                                    Then I�??m required to compare the coordinate system of the layer on the ArcMap with that one on the ArcPad  and to check if they are the same!

                                    [ATTACH=CONFIG]29545[/ATTACH], [ATTACH=CONFIG]29546[/ATTACH], [ATTACH=CONFIG]29547[/ATTACH]


                                    At the end, the captured XYZ are not accurate. Still waiting further feedback from the company