DeepSeek智能时空数据分析（八）：NL2SQL绘制河流-轨迹缓冲区如何生成

序言：时空数据分析很有用，但是GIS/时空数据库技术门槛太高

时空数据分析在优化业务运营中至关重要，然而，三大挑战仍制约其发展：技术门槛高，需融合GIS理论、SQL开发与时空数据库等多领域知识；空间数据缺乏直观可视化工具，导致分析结果难以高效传达；现有产品成本高昂，限制了中小企业应用。

本系列文章将借助DeepSeek等大模型的能力，通过NL2SQL等免费/低成本 AI GIS智能体能力，帮助不熟悉SQL、GIS但是有空间数据分析需求的读者实现最常用的分析功能。

前序文章

《DeepSeek智能时空数据分析（一）：筛选特定空间范围内的POI数据》

《DeepSeek智能时空数据分析（二）：3秒对话式搞定“等时圈”绘制》

《DeepSeek智能时空数据分析（三）：专业级地理数据可视化赏析-《杭州市国土空间总体规划（2021-2035年）》》

《DeepSeek智能时空数据分析（四）：绘制行政区域并定制样式
》

《DeepSeek智能时空数据分析（五）：基于区域人口数量绘制地图散点-大模型搜集数据NL2SQL加工数据》

《DeepSeek智能时空数据分析（六）：大模型NL2SQL绘制城市之间连线》

《DeepSeek智能时空数据分析（七）：4326和3857两种坐标系有什么区别？各自用途是什么？》

参考地理数据可视化案例

前文所述《杭州市国土空间总体规划（2021-2035年）》（公开稿），有很多经典的行政区域绘制案例，例如：
在这里插入图片描述
参考这个区域空间布局结构规划图，前序分享文章《DeepSeek智能时空数据分析（六）：大模型NL2SQL绘制城市之间连线》已经完成了大部分要素通过大模型NL2SQL进行了绘制，效果如下：

在此基础上，本文将参考《杭州市国土空间总体规划（2021-2035年）》-生态空间格局规划图中的河流要素，添加到之前的项目中：
在这里插入图片描述

第一步：导入河流空间数据

按参考案例所示，我们需要导入一段钱塘江的流域数据，可以参考以下样本：（复制后另存为geojson格式文件）

{"features":[{"type":"Feature","id":537369,"properties":{"_draw_type":"line","adcode":"杭州一江"},"geometry":{"type":"LineString","coordinates":[[120.70486134,30.37530722],[120.64186193,30.38938129],[120.55931467,30.38817742],[120.5081997,30.3891033],[120.498346,30.38890378],[120.45547341,30.38136755],[120.44328333,30.37701348],[120.43782048,30.3720213],[120.40371044,30.29406466],[120.38689286,30.26833862],[120.37928981,30.25918249],[120.36733753,30.25353329],[120.35266683,30.25075066],[120.34445826,30.25166549],[120.32375937,30.27115218],[120.31066872,30.28075607],[120.30036669,30.28585279],[120.29242056,30.2883326],[120.27902848,30.28655634],[120.26694757,30.28301832],[120.25033424,30.27422939],[120.24479477,30.26901648],[120.21834372,30.23502326],[120.20034281,30.21860956],[120.18805934,30.21063584],[120.17407879,30.20418767],[120.15436646,30.1975695],[120.13375484,30.19021174],[120.12881178,30.18526395],[120.12567496,30.17915667],[120.12487846,30.16982935],[120.12616887,30.15988996],[120.13240885,30.1477843],[120.15857185,30.12732023],[120.17709146,30.11657745],[120.17958548,30.11314837],[120.18071033,30.1088561],[120.17966882,30.10501712],[120.17589264,30.10259065],[120.15693573,30.09943558],[120.14741363,30.09747859],[120.1363332,30.0940736],[120.12649975,30.09048564],[120.10885708,30.07727781],[120.08501035,30.06362153],[120.07315958,30.05742704],[120.0642676,30.05284841],[120.06065276,30.04932857],[120.05135384,30.04110807],[120.04710499,30.03909052],[120.04381036,30.03753477],[120.03849451,30.03696977],[120.02836394,30.03796053],[120.00357389,30.04191457],[119.98393788,30.04411247],[119.96923775,30.04380813],[119.9618212,30.04288489],[119.95649897,30.04055451],[119.95288368,30.03693575],[119.94921449,30.03012279],[119.94428718,30.0166823],[119.93665499,30.00481442],[119.93225464,29.99765014],[119.92459894,29.98438572],[119.9099833,29.96688419],[119.90274671,29.96154984],[119.89482513,29.95491901],[119.88740273,29.95067936],[119.87968465,29.9487632],[119.87307771,29.94685125],[119.86774616,29.94534418],[119.86350761,29.94287853],[119.86043513,29.93980222],[119.8577417,29.93491649],[119.85285551,29.92592033],[119.84508706,29.91407883],[119.83790256,29.90481547],[119.83007963,29.89766783],[119.82247587,29.89285656],[119.80686175,29.8861082],[119.79734806,29.88135799],[119.78958148,29.87804084],[119.78019822,29.87602848],[119.76558988,29.8708237],[119.75551719,29.86516953],[119.75172239,29.86054374],[119.74786631,29.85269159],[119.74211605,29.84358161],[119.73597007,29.83770564],[119.73010162,29.83392936],[119.7240081,29.82771932],[119.7197494,29.8235223],[119.71505822,29.8191677],[119.70446029,29.8150533],[119.69430958,29.8103082],[119.68742266,29.80594029],[119.67868863,29.79785539],[119.66779602,29.78363756],[119.66149155,29.77596575],[119.65835427,29.76930853],[119.6548051,29.76041781],[119.65324185,29.75147186],[119.65073763,29.73804233],[119.65045659,29.73191658],[119.65156968,29.72732807],[119.65500652,29.72033849],[119.65607743,29.71524952],[119.6579476,29.70668799],[119.66049097,29.70194821],[119.66177224,29.69777704],[119.66071406,29.69417564],[119.65888015,29.69184734],[119.6562053,29.68947213],[119.65154503,29.68509769],[119.64808612,29.68104599],[119.64627626,29.67750665],[119.64503666,29.67435743],[119.6442006,29.67100037],[119.64443401,29.66708868],[119.64607717,29.66327997],[119.64817881,29.65912725],[119.64925463,29.6557141],[119.64857207,29.65273295],[119.64703875,29.65065043],[119.64426634,29.64805309],[119.63872787,29.64630189],[119.63585049,29.6440479],[119.63310011,29.64095854],[119.62821082,29.63623632],[119.62270027,29.63072835],[119.61847298,29.62795018],[119.61380732,29.62506324],[119.60789716,29.62269839],[119.60448241,29.62136363],[119.60127159,29.61911291],[119.59787982,29.61586507],[119.59480384,29.61140428],[119.59208533,29.60689257],[119.58817233,29.60223913],[119.58490955,29.59874091],[119.58039589,29.59499529],[119.57705556,29.59219253],[119.57519761,29.59010575],[119.57369369,29.5876262],[119.57259234,29.58460291],[119.57158318,29.57984776],[119.57048819,29.57203506],[119.56930397,29.56611117],[119.56752498,29.56305229],[119.55852414,29.55477935],[119.55134489,29.54655135],[119.54422549,29.540373],[119.53821381,29.53694944],[119.52945473,29.53348736],[119.52225448,29.53312046],[119.50979034,29.5333871],[119.49314942,29.53514013],[119.48420697,29.53599347],[119.47423671,29.53496018],[119.46267382,29.53552887],[119.45289972,29.53645593],[119.44469325,29.5364747],[119.43010638,29.53619142],[119.42136986,29.53487687],[119.41511691,29.53282646],[119.40850257,29.53067148],[119.40348775,29.52750527],[119.40103156,29.52149258],[119.39706656,29.51279722],[119.39368314,29.50546164],[119.39073961,29.50123976],[119.38642989,29.4970812],[119.38184218,29.49478164],[119.37721769,29.49327161],[119.37242307,29.49292334],[119.36911175,29.49327375],[119.36604708,29.49435612],[119.3640347,29.49596642],[119.36278628,29.49893772],[119.36393371,29.50245562],[119.36953305,29.5092999],[119.373887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或者利用GeoAtlas工具，利用画线工具自行手工标绘一份河流数据：
在这里插入图片描述
获得河流空间数据之后，导入DataV Atlas数据中心：

导入数据中心之后，将河流数据加入到之前项目中：

导入完毕后，在河流数据源选择“转为sql查询”，便于下一步NL2SQL处理：

第二步：大模型NL2SQL生成河流缓冲区

空间数据一般存储用4326，显示用3857，具体可以参考前序文章《DeepSeek智能时空数据分析（七）：4326和3857两种坐标系有什么区别？各自用途是什么？》

因此，在平面地图上绘制河流要素需要完成以下两步：

将几何对象从4326坐标系转换到3857坐标系；
使用缓冲区函数ST_Buffer生成以几何对象为中心、半径为2000米的缓冲区；

所幸我们有大模型的帮助，不需要撰写复杂的空间数据处理SQL；
打开DataV Atlas AI助手，输入以下提示词：

“在3857坐标系下，以这条线为中心，生成2000米为buffer的缓冲区”

在这里插入图片描述
大模型正确理解了我们的意图，并输出sql代码：

SELECT "_draw_type", "adcode", ST_Buffer(ST_Transform("geom", 3857), 1500) AS buffer_geom
FROM "public"."u0piif_hangzhou_river_01";

sql代码含义如下：

ST_Transform(“geom”, 3857)：将geom字段的几何对象从原始坐标系（4326）转换到目标坐标系（3857）。
ST_Buffer(…, 200)：在3857坐标系下，以转换后的几何对象为中心，生成半径为200米的缓冲区。
buffer_geom：为生成的缓冲区几何对象定义别名。