GPS Track Converting and Compression Tool
GPS軌跡轉換壓縮

Select track (*.gpx/*.kml/*.txt) to upload:
選擇要轉換的軌跡檔：
Compression option-keep points if
壓縮條件-留下符合以下條件的點:
Distance between previous point larger than
距離前一個點大於：
Or time difference more than:
或者時間大於：
Input anti-spam code:
輸入圖案英文字：
Press to conver
按下按鈕轉換

這是一個很簡單的GPS軌跡壓縮和轉換的工具。你可以上傳軌跡檔轉成*.cvs檔，產生的*.cvs檔可以直接上傳到Google Document給 gsstrack.html使用。使用的演算法超級簡單：如果下一個點離現在的點不夠遠，就捨棄這個點。壓縮距離是可以選的。這個演算法的確不是太好，但如果 只是用來在Google Map上顯示軌跡，也夠用了。
支援的軌跡檔案格式:

  1. GPX (附檔名：*.gpx)
  2. KML (附檔名：*.kml)
  3. NMEA (附檔名：*.txt)

注意：

  1. 檔案中所有的軌跡會合成一條。
  2. 這個程式並沒有經過大量的測試，目前試過的只有Garmin Vista HCX產生的GPX及GPSBABEL產生的KML及NMEA，所以 如果有任何錯誤發生，請不要驚訝，並email通知我。
  3. 關於GPX檔：waypoint不會被處理，只有track會被處理。
  4. 關於KML檔：KML檔並沒有特定用來描述軌跡的語法；也就是說，有太多種方式可以用來表示軌跡，目前能處理的格式是 根據GPSBABEL轉出的格式：軌跡中的每個點都有一個POINT的PLACEMARK，附有座標和時間的資訊，另外有LinearString用來 劃線，因為線沒有時間的資訊，所以只有POINT的PLACEMARK有處理。
  5. 關於NMEA檔:NMEA並不是用來記錄軌跡用的，所以也是參考GPSBABEL的輸出來處理：目前只處理RMC&GGA，如果只有RMC， 就沒有高度的資訊，但還是可以處理；如果只有GGA，則因為沒有日期的資訊，不會被處理。

This is a very simple track compression utiltiy page. You can upload track file and get *.cvs file, ready to upload to google document to be used by gsstrack.html. The algorithm is quite simple: if the next point is not far away, drop it. You can choose "how far" to drop the point. I know it's not good, but should be good enough for showing track on Google Map.
File format supported:

  1. GPX (extension name *.gpx)
  2. KML (extension name *.kml)
  3. NMEA (extension name *.txt)

NOTE:

  1. All tracks are combined as one.
  2. I don't have much sample track file to verify. The only files I have is GPX generated by Garmin Vista HCX, and those converted by GPSBABEL. Please don't be surprised if there are errors when processing your files. And when it happens, please EMAIL to me.
  3. Note on GPX file: only track data will be processed, and waypoints are ignored.
  4. Note on KML file: there are many ways to describe track in KML. The accepted format is that generated by GPSBABEL, in which every track point is represented as one POINT PLACEMARK with coordinate and timestamp, together with LinearString for line segment. Since no time information in LinearString Placemark, it is not processed. Instead, the POINT PLACEMARK is processed.
  5. Note on NMEA file: many NMEA sentences can be used to describe track. By chekcing output of GPSBABEL, RMC & GGA sentences are processed now. If only RMCs are included, not altitude information is available, but still can be processed. If the fil contains only GGA, it can not be processed for lack of DATE information.
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