Transformation models made by you may be published on the Internet. They may be of interest to all TransLT users in your country or you can store some models for future use or to transmit them to others in this way.

The models are stored in a database kept on our site www.topolt.com and maintained by us. Through your contribution, for which we thank you in advance, we want to achieve a database of transformation models that are frequently used to transform coordinates from one system to another.

To publish a model you must have an account made on your behalf at www.topolt.com. If you are registered then you can post models or change your published models.

Information about transformation model is taken from the selected model or from the selected file. This information can only be changed by editing the transformation model (see section Universal Transformations).

Other information required to publish a model:
• Country or state where the transformation model can be applied. If this is applicable across the globe then choose [Worldwide] or if in the case of a country that has states it is applicable for the whole country choose [Across the country];
• If the model provides a transformation from a CRS type (N,E,H) in a CRS type (φ,λ,h), you need to select whether the model is compatible or not for drawing in Google Earth;
• If you wish to be contacted by other users you can choose to publish your e-mail address.

Recommendation: A transformation model is compatible for drawing in Google Earth if the initial coordinate reference system is of the projection plane (N,E,H) type commonly used in surveying and the final coordinate reference system is of the geographic (φ,λ,h) type on WGS84 ellipsoid or ETRS89 (GRS80), with the longitude relative to the Greenwich Prime Meridian. The initial and final systems can be inverse too if the model supports reverse transformation.

Upload model

When publishing a transformation model you have the possibility to add as well a list with maximum 10 test points with coordinates calculated both in the initial and the final system. Points are taken from the coordinate tables from Universal Transformations section.

If the model you want to publish already exists in the database, you will be prompted to confirm whether to upload or not your model. Searching the existence of a similar model is made according to the initial and final EPSG codes and if these do not exist the search is made after the initial or final CRS names or by model name.

Note: There may be in the database transformation models that have defined the same initial and final CRS, the models can achieve the same transformation via different steps, and thus having different accuracy. For example, for two models that have the same initial and final CRS, if one of the models uses a grid file for transformation and the other uses an approximate 7-parameters transformation, it is recommended that the model with the best accuracy to be published.

Edit model

Changing an existing model from the database can be done only by choosing a transformation model from file. If you want to change a previously published model with another model, you need to save the model to a file (see section Universal Transformations) before editing it. Information about the model is taken from the selected file.

Test points can be placed manually or by copying from the two tables of section Universal Transformations.

Note: The points introduced into the database will be used to test the transformation for the registered model or to be tested with other computer programs. If the test points do not correspond to the transformation done with this model then the model will be removed from the database and you will be notified by e-mail.